CN118476210A - Projection equipment and display control method - Google Patents

Abstract

In some embodiments of the present application, a projection device and a display control method are provided. The method can obtain the interval distance between the optical machine and the projection surface through a distance sensor after receiving an automatic focusing instruction. Then, the current application scene is determined according to the interval distance. If the interval distance is less than the interval judgment threshold, the current application scene is determined to be a close-distance scene, so the first focusing amount can be calculated according to the interval distance; if the interval distance is greater than or equal to the interval judgment threshold, the current application scene is determined to be a long-distance scene, so the second focusing amount can be calculated according to the clarity of the projected content image, and finally the driving motor is controlled according to the first focusing amount or the second focusing amount to adjust the focal length of the optical component. The method can automatically focus according to different data according to different application scenarios, and can quickly adjust the optical component to the optimal focal length state, improve the clarity of the projection picture, and shorten the time consumed by the focusing process.

Description

Projection device and display control method

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Chinese patent applications filed on November 16, 2021, with application number 202111355866.0; filed on March 31, 2022, with application number 202210343443.5; and filed on May 19, 2022, with application number 202210557800.8, all of which are incorporated by reference into this application.

Technical Field

The present application relates to the technical field of display devices, and in particular to a projection device and a display control method.

Background Art

A projection device is a display device that can project images or videos onto a screen. The projection device can project laser light of a specific color onto the screen through the refraction of an optical lens assembly to form a specific image. During the projection process, it is necessary to keep a certain distance between the projection device and the screen so that the image formed on the screen can meet the focal length range of the optical lens assembly to obtain a clear image.

In order to adapt to complex application scenarios and screens of different specifications, the focal length of the optical lens assembly of the projection device needs to be adjusted. For example, the user can manually adjust the distance between the lenses in the optical lens assembly by observing the clarity of the image projected by the projection device, so that the overall focal length of the optical lens assembly changes. As the user adjusts the process, the clarity of the projected image will change, and the adjustment will stop when the clarity meets the user's needs.

Obviously, the manual focusing process is cumbersome and inconvenient for users. For this reason, some projection devices also support automatic focusing. The automatic focusing function can be achieved by setting a drive motor so that the drive motor drives part of the lens in the optical lens assembly to move for focusing. The projection device also detects the clarity of the projected image and controls the drive motor to start or stop running according to the detected clarity to achieve automatic focusing. However, due to the cumbersome control of the clarity detection and the start and stop process of the drive motor, the above-mentioned automatic focusing method takes a long time and has poor anti-interference ability, which reduces the user experience.

Summary of the invention

On the one hand, some embodiments of the present application provide a projection device, including: an optical machine, a lens, a distance sensor, a camera, and a controller. The optical machine is configured to project the playback content onto the projection surface; the lens includes an optical component and a focus motor; the focus motor is connected to the optical component to adjust the focal length of the optical component; the distance sensor is configured to detect the interval distance between the projection surface and the optical machine; the camera is configured to capture the projection content image; the controller is configured to: in response to an automatic focusing instruction, obtain the interval distance; if the interval distance is less than the interval judgment threshold, calculate a first focus amount according to the interval distance, and control the focus motor to adjust the focal length of the optical component according to the first focus amount; if the interval distance is greater than or equal to the interval judgment threshold, calculate a second focus amount according to the clarity of the projection content image, and control the focus motor to adjust the focal length of the optical component according to the second focus amount.

On the other hand, some embodiments of the present application also provide a display control method applied to a projection device, wherein the projection device includes an optical machine, a distance sensor, a camera and a controller; wherein the optical machine includes an optical component and a focusing motor, and the focusing motor is connected to the optical component to adjust the focal length of the optical component; the method includes: in response to an automatic focusing instruction, obtaining the interval distance through the distance sensor; if the interval distance is less than an interval judgment threshold, calculating a first focusing amount according to the interval distance, and controlling the focusing motor to adjust the focal length of the optical component according to the first focusing amount; if the interval distance is greater than or equal to the interval judgment threshold, calculating a second focusing amount according to the clarity of the projection content image, and controlling the focusing motor to adjust the focal length of the optical component according to the second focusing amount.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a projection state of a projection device in an embodiment of the present application;

FIG2 is a schematic diagram of the structure of a projection device in an embodiment of the present application;

FIG3 is a schematic diagram of an optical-mechanical architecture of a projection device according to an embodiment of the present application;

FIG4 is a schematic diagram of an optical path of a projection device in an embodiment of the present application;

FIG5 is a schematic diagram of a circuit structure of a projection device according to an embodiment of the present application;

FIG6 is a schematic diagram of a system framework of a projection device in an embodiment of the present application;

FIG7 is a schematic diagram of a lens structure of a projection device in an embodiment of the present application;

FIG8 is a schematic diagram of a lens projection optical path in an embodiment of the present application;

FIG9 is a schematic diagram of the distance sensor and camera structure in an embodiment of the present application;

FIG10 is a schematic diagram of the process of the automatic focusing method in an embodiment of the present application;

FIG11 is a schematic diagram of a process of focusing based on clarity in an embodiment of the present application;

FIG12 is a schematic diagram of a process for detecting the number of target objects in an embodiment of the present application;

FIG13 is a schematic diagram of a multi-stage image focusing process in an embodiment of the present application;

FIG14 is a schematic diagram of a process of cutting an image in an embodiment of the present application;

FIG15 is a timing diagram of an automatic focusing method according to an embodiment of the present application;

FIG16 is a schematic diagram of a signaling interaction timing sequence of a projection device realizing a radiating eye function according to another embodiment of the present application;

FIG17 is a schematic diagram of a signaling interaction timing sequence of a projection device implementing a display image correction function according to another embodiment of the present application;

FIG18 is a schematic diagram of a flow chart of an automatic focusing algorithm implemented by a projection device according to another embodiment of the present application;

FIG19 is a schematic diagram of a flow chart of a projection device implementing a trapezoidal correction and obstacle avoidance algorithm according to another embodiment of the present application;

FIG20 is a schematic diagram of a flow chart of a projection device implementing an entry algorithm according to another embodiment of the present application;

FIG21 is a schematic diagram of a flow chart of an anti-eye-shooting algorithm implemented by a projection device according to another embodiment of the present application;

FIG22 is a schematic diagram of an application scenario of a screen brightness adjustment method according to an embodiment of the present application;

FIG23 is a second schematic diagram of an application scenario of a method for adjusting screen brightness according to an embodiment of the present application;

FIG24 is a schematic diagram of a flow chart of a method for adjusting screen brightness according to an embodiment of the present application;

FIG25 is a schematic diagram 1 of multiple screen partitions according to an embodiment of the present application;

FIG26 is a second schematic diagram of multiple screen partitions according to an embodiment of the present application;

FIG27 is a first schematic diagram of target screen partitions according to an embodiment of the present application;

FIG28 is a second schematic diagram of target screen partitions according to an embodiment of the present application;

FIG29 is a third schematic diagram of target screen partitions according to an embodiment of the present application;

FIG30 is a schematic diagram 1 of adjusting screen brightness according to an embodiment of the present application;

Figure 31 is a second schematic diagram of adjusting screen brightness according to an embodiment of the present application.

DETAILED DESCRIPTION

In order to make the purpose and implementation method of the present application clearer, the exemplary implementation method of the present application will be clearly and completely described below in conjunction with the drawings in the exemplary embodiments of the present application. Obviously, the described exemplary embodiments are only part of the embodiments of the present application, not all of the embodiments.

The embodiments of the present application can be applied to various types of projection devices. The following will take the projection device as an example to explain the projection device and the automatic focusing method.

Projection equipment is a device that can project images or videos onto a screen. Projection equipment can be connected to computers, broadcasting networks, the Internet, VCD (Video Compact Disc), DVD (Digital Versatile Disc Recordable), game consoles, DV (Digital Video), etc. through different interfaces to play corresponding video signals. Projection equipment is widely used in homes, offices, schools, and entertainment venues.

FIG. 1 is a schematic diagram of the placement of a projection device according to an embodiment of the present application, and FIG. 2 is a schematic diagram of the optical path of the projection device according to an embodiment of the present application.

In some embodiments, referring to Figures 1 and 2, a projection device provided by the present application includes a projection screen 1 and a device for projection 2. The projection screen 1 is fixed at a first position, and the device for projection 2 is placed at a second position so that the image projected by it matches the projection screen 1.

The projection device includes a laser light source 100, an optical machine 200, a lens 300, and a projection medium 400. The laser light source 100 provides illumination for the optical machine 200, and the optical machine 200 modulates the light source beam and outputs it to the lens 300 for imaging, and projects it to the projection medium 400 to form a projection picture.

In some embodiments, the laser light source 100 of the projection device includes a laser assembly 110 and an optical lens assembly 120. The light beam emitted by the laser assembly 110 can pass through the optical lens assembly 120 to provide lighting for the optical machine. For example, the optical lens assembly 120 requires a higher level of environmental cleanliness and airtightness; while the chamber where the laser assembly is installed can be sealed with a lower level of dustproofness to reduce the sealing cost.

In some embodiments, the light engine 200 of the projection device may be implemented as a blue light engine, a green light engine, a red light engine, and may also include a heat dissipation system, a circuit control system, etc. It should be noted that, in some embodiments, the light emitting component of the projection device may also be implemented by an LED (Light Emitting Diode: light emitting diode) light source.

FIG3 is a schematic diagram of a circuit architecture of a projection device according to an embodiment of the present application. In some embodiments, the projection device may include a display control circuit 10, a laser light source 20, at least one laser driving component 30, and at least one brightness sensor 40. The laser light source 20 may include at least one laser corresponding to the at least one laser driving component 30. The at least one refers to one or more, and the plurality refers to two or more.

Based on the circuit architecture, the projection device can achieve adaptive adjustment. For example, by setting a brightness sensor 40 in the light output path of the laser light source 20, the brightness sensor 40 can detect a first brightness value of the laser light source and send the first brightness value to the display control circuit 10.

The display control circuit 10 can obtain the second brightness value corresponding to the driving current of each laser, and when it is determined that the difference between the second brightness value of the laser and the first brightness value of the laser is greater than the difference threshold, it is determined that a COD (Catastrophic Optical Damage) failure occurs in the laser; the display control circuit can adjust the current control signal of the laser driving component corresponding to the laser until the difference is less than or equal to the difference threshold, thereby eliminating the COD failure of the blue laser; the projection device can eliminate the COD failure of the laser in time, reduce the damage rate of the laser, and improve the image display effect of the projection device.

FIG. 4 is a schematic diagram of the structure of a projection device according to an embodiment of the present application.

In some embodiments, the laser light source 20 in the projection device may include independently arranged blue laser 201, red laser 202 and green laser 203. The projection device may also be referred to as a three-color projection device. The blue laser 201, the red laser 202 and the green laser 203 are all module lightweight (Mirai Console Loader, MCL) packaged lasers, which are small in size and are conducive to the compact arrangement of the optical path. In some embodiments, the projection device may be configured with a camera for cooperating with the projection device to achieve adjustment and control of the projection process. For example, the camera configured with the projection device may be specifically implemented as a 3D (3-Dimensional) camera or a binocular camera; when the camera is implemented as a binocular camera, it specifically includes a left camera and a right camera; the binocular camera may obtain the screen corresponding to the projection device, that is, the image and playback content presented by the projection surface, and the image or playback content is projected by the built-in optical machine of the projection device.

When the projection device moves, its projection angle and distance to the projection surface change, which will cause the projected image to deform. The projected image will appear as a trapezoidal image or other deformed image. The projection device controller can achieve automatic trapezoidal correction based on the image taken by the camera, by coupling the angle between the optical machine and the projection surface and the correct display of the projection image.

FIG. 5 is a schematic diagram of a circuit structure of a projection device according to an embodiment of the present application.

In some embodiments, the laser driving component 30 may include a driving circuit 301, a switching circuit 302, and an amplifying circuit 303. The driving circuit 301 may be a driving chip. The switching circuit 302 may be a metal-oxide-semiconductor (MOS) tube.

The driving circuit 301 is respectively connected to the switch circuit 302, the amplifier circuit 303 and the corresponding laser included in the laser light source 20. The driving circuit 301 is used to output a driving current to the corresponding laser in the laser light source 20 through the VOUT terminal based on the current control signal sent by the display control circuit 10, and transmit the received enable signal to the switch circuit 302 through the ENOUT terminal.

The display control circuit 10 is further configured to determine the amplified driving voltage as the driving current of the laser, and obtain a second brightness value corresponding to the driving current.

In some embodiments, the amplifier circuit 303 may include: a first operational amplifier A1 , a first resistor (also called a sampling power resistor) R1 , a second resistor R2 , a third resistor R3 , and a fourth resistor R4 .

In some embodiments, the display control circuit 10 is also used to restore the current control signal of the laser driving component corresponding to the laser to the initial value when the difference between the second brightness value of the laser and the first brightness value of the laser is less than or equal to the difference threshold, and the initial value is the size of the PWM current control signal of the laser under normal conditions. Thus, when a COD failure occurs in the laser, it can be quickly identified and measures to reduce the driving current can be taken in time to reduce the continuous damage to the laser itself and help it to recover. The whole process does not require disassembly and human intervention, which improves the reliability of the use of the laser light source and ensures the projection display quality of the laser projection device.

In some embodiments, the controller includes a central processing unit (CPU), a video processor, an audio processor, a graphics processing unit (GPU), RAM Random Access Memory (RAM), ROM (Read-Only Memory, ROM), a first interface to an nth interface for input/output, a communication bus (Bus), etc.

In some embodiments, after the projection device is started, it can directly enter the display interface of the last selected signal source, or the signal source selection interface, where the signal source can be a preset video on demand program, or at least one of an HDMI interface, a live TV interface, etc. After the user selects a different signal source, the projector can display content obtained from different signal sources.

In some embodiments, the projection device may be configured with a camera for cooperating with the projection device to achieve adjustment and control of the projection process. For example, the camera configured with the projection device may be specifically implemented as a 3D camera or a binocular camera; when the camera is implemented as a binocular camera, it specifically includes a left camera and a right camera; the binocular camera may obtain the image and playback content presented by the screen corresponding to the projection device, that is, the projection surface, and the image or playback content is projected by the built-in optical machine of the projection device. Figure 6 is a schematic diagram of the system framework for realizing display control of a projection device in an embodiment of the present application.

In some embodiments, the projection device has the characteristics of a telephoto micro-projector, and its controller can control the display of the projection light image through a preset algorithm to achieve functions such as automatic trapezoidal correction of the display screen, automatic screen entry, automatic obstacle avoidance, automatic focusing, and anti-eye-shooting.

In some embodiments, the projection device is configured with a gyroscope sensor; when the device is moving, the gyroscope sensor can sense the position movement and actively collect movement data; the collected data is then sent to the application service layer through the system framework layer to support the application data required during user interface interaction and application interaction. The collected data can also be used for data calls by the controller in the algorithm service implementation.

In some embodiments, the projection device is configured with a time-of-flight sensor. After the time-of-flight sensor collects corresponding data, the data will be sent to the corresponding time-of-flight service of the service layer; after the above-mentioned time-of-flight service obtains the data, it will send the collected data to the application service layer through the process communication framework, and the data will be used for interactive use such as controller data calls, user interfaces, and program applications.

In some embodiments, the projection device is configured with a camera for capturing images, and the camera can be implemented as a binocular camera, a depth camera, a 3D camera, etc.; the camera capture data will be sent to the camera service, and then the camera service will send the captured image data to the process communication framework, and/or the projection device correction service; the projection device correction service can receive the camera capture data sent by the camera service, and the controller can call the corresponding control algorithm in the algorithm library according to the different functions to be implemented.

In some embodiments, data is interacted with the application service through the process communication framework, and then the calculation results are fed back to the correction service through the process communication framework; the correction service sends the obtained calculation results to the projection device operating system to generate control signals, and sends the control signals to the optical machine control driver to control the optical machine working conditions and realize automatic correction of the displayed image.

In some embodiments, the projection device uses an automatic focusing algorithm and a laser ranging device to obtain the current object distance to calculate the initial focal length and the search range; the projection device then drives the camera to take pictures and uses a corresponding algorithm to evaluate the clarity.

The projection device searches for the best possible focal length within the above search range based on the search algorithm, and then repeats the above steps of taking pictures and evaluating clarity, and finally finds the optimal focal length through clarity comparison to complete automatic focusing.

For example, after the projection device is started, the user moves the device; the projection device automatically completes the calibration and refocuses, and the controller detects whether the autofocus function is turned on; when the autofocus function is not turned on, the controller ends the autofocus service; when the autofocus function is turned on, the projection device obtains the detection distance of the time-of-flight sensor through the middleware for calculation;

The controller queries the preset mapping table according to the acquired distance to obtain the focal length of the projection device; then the middleware sets the acquired focal length to the optical machine of the projection device; after the optical machine emits laser at the above focal length, the camera executes the photo command; the controller determines whether the focus adjustment of the projection device is completed according to the acquired captured image and evaluation function;

If the judgment result meets the preset completion conditions, the control of the automatic focusing process ends; if the judgment result does not meet the preset completion conditions, the middleware will fine-tune the focal length parameters of the optical machine in the projection device. For example, the focal length can be gradually fine-tuned using a preset step length, and the adjusted focal length parameters can be set to the optical machine again; thereby achieving repeated photo taking and clarity evaluation steps, and finally finding the optimal focal length through clarity comparison to complete automatic focusing.

FIG7 is a schematic diagram of the lens structure of a projection device in some embodiments. In order to support the automatic focusing process of the projection device, as shown in FIG7 , the lens 300 of the projection device may further include an optical component 310 and a drive motor 320. The optical component 310 is a lens group composed of one or more lenses, which can refract the light emitted by the optical machine 200 so that the light emitted by the optical machine 200 can be transmitted to the projection surface to form a transmission content image.

The optical assembly 310 may include a lens barrel and a plurality of lenses disposed in the lens barrel. Depending on whether the position of the lens can be moved, the lens in the optical assembly 310 may be divided into a movable lens 311 and a fixed lens 312. By changing the position of the movable lens 311 and adjusting the distance between the movable lens 311 and the fixed lens 312, the overall focal length of the optical assembly 310 may be changed. Therefore, the driving motor 320 may be connected to the movable lens 311 in the optical assembly 310 to drive the movable lens 311 to move its position, thereby realizing an automatic focusing function.

It should be noted that the focusing process described in some embodiments of the present application refers to changing the position of the movable lens 311 by driving the motor 320, thereby adjusting the distance between the movable lens 311 and the fixed lens 312, that is, adjusting the image plane position. Therefore, the imaging principle of the lens combination in the optical assembly 310, the adjustment of the focal length is actually the adjustment of the image distance, but in terms of the overall structure of the optical assembly 310, adjusting the position of the movable lens 311 is equivalent to adjusting the overall focal length of the optical assembly 310. Therefore, for the convenience of description, the adjustment of the focal length is used to illustrate the above process in the subsequent embodiments.

The driving motor 320 can be connected to the moving lens 311 through a specific transmission mechanism. The transmission principle of the transmission mechanism can be any transmission structure that converts a rotational motion into a moving motion. For example, a worm gear transmission structure, a ball screw transmission structure, a threaded screw transmission structure, etc. For the threaded screw transmission structure, a frame is provided at the outer edge of the moving lens 311, and a thread can be provided on the frame. The power output shaft of the driving motor 320 is connected to a screw, and the screw cooperates with the thread on the frame, so that the rotational motion output by the driving motor 320 can be converted into the moving motion of the frame, thereby driving the moving lens 311 to move in the lens barrel.

Since the moving lens 311 has different effects on the overall focal length of the optical component 310 when it is in different positions, the projection device can rotate the moving lens 311 to a specific angle or number of turns by the driving motor 320 so that the moving lens 311 is in a corresponding position. In order to achieve the above functions, the driving motor 320 can be a stepping motor, a servo motor, etc. with a controllable rotation angle. During the focusing process, the controller 500 of the projection device can send a movement instruction to the driving motor 320, and the movement instruction can include angle data required to control the rotation of the driving motor 320. For example, for the driving motor 320 in the form of a stepping motor, the movement instruction sent by the controller 500 may include a pulse signal corresponding to the required rotation angle. After sending the movement instruction to the driving motor 320, the driving motor 320 can parse the pulse signal from the movement instruction and rotate according to the pulse signal.

It should be noted that, in order to be able to adjust the movable lens 311 to a specific position, the correspondence between the moving distance of the movable lens 311 and the rotation angle of the driving motor 320 can be calculated in advance according to the internal structure of the projection device. The correspondence between the moving distance and the rotation angle can be a linear relationship, which is affected by the transmission ratio of the transmission mechanism. When focusing, the projection device can first calculate the target position of the movable lens 311, and then calculate the required moving distance of the movable lens 311 during the focusing process by subtracting the target position from the current position of the movable lens 311. Then, based on the correspondence between the moving distance and the rotation angle, the angle that the driving motor 320 needs to rotate is calculated, thereby generating a moving instruction and sending it to the driving motor 320.

Since the movable lens 311 can usually only move along the lens barrel and in the lens barrel, the movable lens 311 has a travel limit during the focusing process. FIG8 is a schematic diagram of the lens projection optical path in some embodiments. As shown in FIG8, for the convenience of description, the end of the movable lens 311 closest to the optical machine can be called the near end, and the end of the movable lens 311 farthest from the optical machine can be called the far end. The overall moving stroke of the movable lens 311 is the distance between the near end and the far end. In some embodiments, in order to facilitate accurate adjustment of the projection effect, the actual focusing range of the projection device can be within the travel range of the movable lens 311. For example, after the movable lens 311 is moved to the near end, the driving motor 320 is adjusted forward by 300 steps to meet the focusing requirements of the projection device at the closest projection distance; and if it is adjusted forward by 900 steps from the near end, the focusing requirements of the projection device at the farthest projection distance can be met. The actual focusing range can be the position interval corresponding to the adjustment of the driving motor 320 by 300 steps to 900 steps.

Since the focusing process can also be affected by comprehensive factors such as the characteristics of the driving motor, environmental characteristics, and placement posture, the projection device needs to set a certain adjustment margin at the near and far positions to meet the actual projection effect. Therefore, in some embodiments, the adjustment interval of the projection device can increase some adjustment margins on the basis of the actual focusing range. For example, for the position interval corresponding to the adjustment of 300 steps to 900 steps, after setting a 100-step adjustment margin, the position 200 steps away from the near end and the position 1000 steps away can be set as the adjustment start point and adjustment end point to form the final focusing range.

When the distance between the projection device and the projection surface is different, the lens of the projection device needs to adjust different focal lengths to transmit a clear image on the projection surface. During the projection process, the distance between the projection device and the projection surface will require different focal lengths due to the different placement positions of the user. Therefore, in order to adapt to different usage scenarios, the projection device needs to adjust the focal length of the optical component 310.

In some embodiments, the projection device may support a manual focus adjustment function, that is, an interactive button may be provided on the projection device, or the projection device may be equipped with a remote control, and the user may interact with the projection device through the focus adjustment button on the projection device or the focus adjustment button on the remote control. During the interaction, the controller 500 of the projection device may generate a movement instruction according to the user's button operation, and send the movement instruction to the drive motor to control the drive motor to drive the movable lens 311 to move and change the focal length of the optical component.

For example, when the user finds that the projected image is not clear when using the projection device, the user can press the "forward" button on the projection device. In response to the user's button operation at this time, the projection device can generate a movement instruction to control the movable lens 311 to move away from the optical machine, and send the movement instruction to the drive motor. After receiving the movement instruction, the drive motor rotates in the positive (clockwise) direction to output torque to drive the movable lens 311 to move away from the optical machine. As the movable lens 311 moves, the clarity of the image transmitted by the projection device will change, and the user can choose to continue focusing or stop focusing according to the clarity of the image until a satisfactory image effect is presented.

During manual focus adjustment, the controller 500 of the projection device can implement corresponding control of the drive motor 320 according to the preset interaction rules. That is, in some embodiments, the controller 500 can determine the rotation angle of the drive motor according to the duration of the user's key press. When the focus adjustment amount is large, the user can press the focus adjustment button for a long time; when the focus adjustment amount is small, the user can press the focus adjustment button for a short time.

In some embodiments, the controller 500 of the projection device can also determine the rotation angle of the drive motor according to the number of times the user presses a button. For example, when the projection device is in a coarse adjustment state, the adjustment amount for each button operation is set to 100 steps, corresponding to one rotation of the drive motor. When the user adjusts 300 steps to the far end, the user needs to press the "forward" button three times in succession.

The projection device can also automatically adjust the focal length according to the projection effect. In some embodiments of the present application, a focusing method based on the relationship between the spacing distance and the focal length is provided. That is, the projection device can detect the spacing distance between the optical machine and the projection surface. Since different spacing distances require different focal lengths to present a clear picture, after detecting the spacing distance relative to the projection surface, the projection device can obtain a corresponding focal length. Then send a movement instruction to the drive motor to adjust the overall focal length of the optical component to a corresponding focal length.

FIG9 is a schematic diagram of the distance sensor and camera structure in some embodiments. As shown in FIG9 , the projection device may also have a built-in or external camera 700, and the camera 700 may capture the image projected by the projection device to obtain the projection content image. The projection device then performs a clarity detection on the projection content image to determine whether the current lens focal length is appropriate, and adjusts the focal length if it is not appropriate. When automatically focusing based on the projection content image captured by the camera 700, the projection device may continuously adjust the lens position and take pictures, and find the focusing position by comparing the clarity of the front and rear position pictures, thereby adjusting the movable lens 311 in the optical component to a suitable position. For example, the controller 500 may first control the drive motor 320 to gradually move the movable lens 311 from the focus starting position to the focus end position, and continuously obtain the projection content image through the camera 700 during this period. Then, by performing a clarity detection on multiple projection content images, the position with the highest clarity is determined, and finally the drive motor 320 is controlled to adjust the movable lens 311 from the focus terminal to the position with the highest clarity to complete the automatic focusing.

In order to obtain a better focusing effect and increase the focusing speed, an automatic focusing method is also provided in some embodiments of the present application. FIG10 is a flow chart of the automatic focusing method in some embodiments. The focusing method can take into account the advantages of the above-mentioned automatic focusing method and adopt different focusing methods according to different application scenarios. The automatic focusing method can be applied to a projection device, and in order to meet the implementation of the automatic focusing method, the projection device may include an optical machine 200, a lens 300, a distance sensor 600, a camera 700 and a controller 500. Among them, as shown in FIG10, the controller 500 can be used to execute the program steps corresponding to the automatic focusing method, including the following contents:

Obtain an automatic focus instruction. The automatic focus instruction refers to a control instruction for triggering the projection device to automatically focus. The automatic focus instruction can be manually input by the user. For example, after the projection device is powered on, the user can press the automatic focus button on the projection device or the remote control of the projection device to make the projection device automatically focus, that is, obtain the automatic focus instruction.

In some embodiments, the automatic focus instruction can also be automatically generated according to the control program built into the projection device. For example, when the projection device detects the first video signal input after power-on, the automatic focus can be triggered, and the automatic focus instruction is generated. For another example, when the projection device detects that its own placement posture or setting position has changed, in order to eliminate the impact of the change process, when the placement posture or setting position is detected to have changed, the projection device can automatically adjust the focus, that is, generate an automatic focus instruction.

After obtaining the auto-focus instruction, the controller 500 of the projection device can respond to the auto-focus instruction and obtain the interval distance through the distance sensor 600. Among them, the distance sensor 600 can be a sensor device based on the time of flight (TOF) principle, such as a laser radar, an infrared radar, etc., which can detect the target distance. The distance sensor 600 can be set at the position of the optical machine 200, including a signal transmitter and a receiver. In the process of detecting the interval distance, the transmitter of the distance sensor 600 can transmit a wireless signal in the direction of the projection surface. After the wireless signal contacts the projection surface, it will be reflected back to the receiving end of the distance sensor 600, so that the signal flight time is calculated according to the time when the transmitter sends the signal and the time when the receiver receives the signal. Combined with the flight speed, the actual flight distance of the wireless signal can be obtained, and then the interval distance between the projection surface and the optical machine can be calculated.

After obtaining the interval distance, the projection device can judge the interval distance and determine the type of the current application scene. In some embodiments, the application scene types can include two types: close-range scenes and long-range scenes. The two scenes can be determined by comparing the size relationship between the interval distance and the preset interval judgment threshold. Among them, the interval judgment threshold can be set according to the purpose of the projection device. For example, for home projection equipment, the interval judgment distance can be set to 1300mm. After obtaining the interval distance, the interval distance can be compared with the interval judgment threshold. When the interval distance is less than the interval judgment threshold, the current application scene is determined to be a close-range scene; and when the interval distance is greater than or equal to the interval judgment threshold, the current application scene is determined to be a long-range scene.

For close-range scenes, since the signal emitted by the distance sensor 600 is less affected by objects in the environment, the distance sensor 600 can more accurately detect the distance between the projection surface and the optical machine 200. Therefore, when it is detected that the current application scene is a close-range scene, the TOF close-range distance measurement with high accuracy and small deviation can be fully utilized to achieve fast focusing based on the distance measurement method. That is, if the interval distance is less than the interval judgment threshold, the first focusing amount is calculated according to the interval distance, and the driving motor 320 is controlled to adjust the focal length of the optical component 310 according to the first focusing amount.

For example, after determining that the current application scenario is a close-range scenario, the projection device can call the stored interval distance and focal length comparison table, and then query the focal length corresponding to the current interval distance from the comparison table. The focal length data can be expressed as the distance of the moving lens 311 relative to the near end or far end of the stroke, and the direction, angle, and number of turns that the corresponding driving motor 320 needs to rotate. Finally, based on the focal length data obtained by the query, a movement instruction is generated, and the movement instruction is sent to the driving motor 320 to control the driving motor 320 to drive the moving lens 311 to move to the target position.

Since the initial position of the movable lens 311 during the focusing process is uncertain and mainly depends on the position of the movable lens 311 after the last focusing, in order to realize the above-mentioned automatic focusing process based on the interval distance, the projection device can be initialized each time it is turned on, and the movable lens 311 can be adjusted to the near or far position, so that the driving motor 320 can move directly based on the near or far end after receiving the movement instruction.

However, for a projection device that is not frequently moved, the spacing distance between the optical machine 200 and the projection surface 400 will not change frequently. In order to avoid repeating the focusing operation every time the device is turned on, it can be set not to adjust the focal length of the optical component 310 when the device is turned on. When the projection device obtains an automatic focusing instruction, the optical component 310 is first moved to the near end or the far end, and then adjusted to the target position according to the movement instruction.

In some embodiments, the projection device can also obtain the current position of the movable lens 311 after determining the position corresponding to the adapted focal length according to the interval distance, and calculate the target position to be adjusted according to the current position and the position corresponding to the focal length, thereby generating a movement instruction. Obviously, the movement instruction generated at this time includes the direction, angle, and number of turns of the driving motor that need to be rotated under the current position condition.

In order to calculate the target position, a position storage module can be pre-configured in the projection device, and the position storage module can record the rotation of the drive motor 320 in real time during the focusing process. Obviously, the focusing process that can trigger the real-time recording can be a manual focusing process or an automatic focusing process. Then, by setting the credibility, the recorded current position is evaluated. The credibility can represent the validity of the currently memorized position information through a specific value. That is, when the credibility is a first value, it means that the currently memorized position information is valid; when the credibility is a second value, it means that the currently memorized position information is invalid. In order to indicate the validity, the first value can be set to be greater than the second value. For example, setting the first value to 1 means that the current memorized information is valid; setting the second value to 0 means that the current memorized information is invalid. The validity of the current memorized information can also be represented by other values, such as an odd number indicating that the memorized information is valid, and an even number indicating that the memorized information is invalid. After the user enters the manual focusing interface, the controller 500 can notify the position storage module to focus. After receiving the notification, the position storage module sets the position credibility to 0 and waits for the focusing process to be completed. The projection device then receives the user's operation key. If the user adjusts the focus through the direction key, the lens 311 is moved according to the user's requirements, and the user's operation process, including the moving direction and the number of moving steps, is memorized in real time through temporary variables.

When memorizing the number of moving steps, the actual number of moving steps of the driving motor may be used as the standard, so as to achieve position adjustment with different precisions at different focusing positions. For example, each time the user performs a focusing operation, the controller 500 may send a command to the driving motor 320 to move 20 steps in a fixed direction, but when the moving lens 311 has moved to the edge of the adjustable range, in response to each operation of the user, the controller 500 may send a moving command to the driving motor 320 with an actual number of moving steps less than 20 steps, and at this time, the lens position should be recorded based on the actual number of steps.

When the user exits manual focusing, the controller 500 can notify the position storage module that the focusing is finished, and write the moving direction and number of steps of the drive motor 32 during this focusing process. After receiving the notification, the position storage module updates the stored position and sets the position credibility to the first value for the next focusing. If an abnormal exit or crash occurs during the manual focusing process, when entering manual focusing again, the controller 500 will still issue a notification to start focusing, and the position storage module will receive notifications of the start of focusing twice in a row. At this time, it can be regarded as an abnormality. In order to reduce the impact of abnormal conditions, the position storage module can set the credibility to the second value before being calibrated, that is, it is always in an untrustworthy state.

Similarly, when the projection device moves the position of the lens 311 during the automatic focusing process, the position storage module also needs to record the rotation of the drive motor in real time, and constrain the recorded position information by setting the credibility. For example, after the automatic focusing process starts, the position credibility of the position storage module is set to 0, indicating that the current position is in an untrusted state; if a focus start notification is received, and the focus start is received again without receiving the focus end notification, in order to ensure the accuracy of the position memory, it is considered that there is an abnormality in the previous focusing process, and an abnormal flag is set, and before the automatic focusing completes the position calibration, the position credibility is always maintained at state 0.

After receiving the focus end notification normally, if the current focus process is automatic focus, since the automatic focus is controlled by the program, it may succeed or fail, and some failure reasons may affect the accuracy of the position memory. Therefore, when the automatic focus fails, the abnormal flag is set and the credibility is set to 0 to ensure that the position of the drive motor 320 can be calibrated once during the next automatic focus process. If the automatic focus is successful, it is determined whether the current position memory abnormal flag is 1. If it is 1, in addition to updating the recorded position, the abnormal flag needs to be cleared synchronously to ensure that the stored position can be fully used during the next automatic focus.

For long-distance scenes, since the signal emitted by the distance sensor 600 is easily affected by the environment, resulting in a decrease in TOF accuracy, it is not suitable for direct use. Focusing based on the projection content image can greatly reduce the effective focal length interval search range of the focusing process, improve the focusing speed, and there is no need to worry about falling into the problem of local invalid focusing. Therefore, the projection device can automatically focus by combining the interval distance with image detection. Figure 11 is a schematic diagram of the process of focusing based on clarity in some embodiments. As shown in Figure 11, if the interval distance is greater than or equal to the interval judgment threshold, the second focusing amount is calculated according to the clarity of the projection content image, and the drive motor 320 is controlled according to the second focusing amount to adjust the focal length of the optical component 310.

In some embodiments, when calculating the second focus amount according to the clarity of the projected content image, the controller 500 may first send a first movement instruction to the drive motor 320 to control the drive motor 320 to move the optical assembly 310 from the focus starting position to the focus ending position. During the movement of the optical assembly 310, the camera 700 is turned on to continuously capture images. Then, the projected content image captured by the camera 700 is obtained at a preset frequency, wherein each projected content image is associated with a focus position. Therefore, the clarity of the projected content image can be calculated, and then the best focus position can be found according to the clarity of the projected content image.

For example, after determining that the interval distance is greater than or equal to the interval judgment threshold, the controller 500 can control the driving motor 320 to rotate to drive the movable lens 311 to move from the focus starting position to the focus end position, and continuously take pictures and calculate the clarity through the camera 700 during the movement. Among them, the clarity of the projected content image can be achieved based on a variety of methods such as frequency domain function, grayscale function, information entropy, etc. Then, the search direction is confirmed by comparing the clarity of the projected content image before and after the photo shooting time sequence, that is, the direction from low clarity to high clarity, so as to find the position corresponding to the projected content image with the highest clarity.

In order to meet the needs of calculating the focus amount, the projection device can also be configured with multiple functional units, such as a strategy selection unit, a motor control unit, an image acquisition unit (Camera), a clarity sorting unit, etc., and each functional unit can work independently of each other. For example, after the strategy selection unit determines to calculate the second focus amount based on the clarity of the projection content image, it can notify the motor control unit to control the drive motor to drive the mobile lens 311 to complete the search interval at one time according to the set search interval, without stopping to wait for taking pictures and clarity calculation. In addition, for a single focusing process, the controller 500 can send position information to the image acquisition unit and write position information to the image clarity evaluation unit when the drive motor 320 rotates to a specific state to achieve synchronization among the three.

It can be seen from the above technical solutions that the automatic focusing method provided in the above embodiments can determine the current application scenario according to the interval distance. In the close-range scenario, the focusing amount is calculated according to the interval distance, thereby making full use of the characteristics of high accuracy and small deviation of TOF close-range distance measurement, and realizing fast focusing based on the distance measurement method. In the long-range scenario, the focusing amount is calculated according to the clarity of the projected content image, thereby overcoming the disadvantage of poor accuracy of TOF long-range distance measurement, reducing the number of repeated focusing times, and improving the focusing speed.

In some embodiments, distance sensors such as laser radar and infrared radar can scan within a specific plane and determine the environmental state between the projection surface 400 and the optical machine 200 based on the scanning results to reduce the impact of environmental factors on the focusing process.

FIG. 12 is a schematic diagram of a process for detecting the number of target objects in some embodiments. As shown in FIG. 12 , the method for detecting the number of target objects includes the following steps:

Step 1201, when acquiring the interval distance, the projection device may acquire the distance detection frame data generated by the distance sensor 600 during multiple scanning processes;

Step 1202, traverse the number of target objects in multiple distance detection frame data;

Step 1203, setting the reliability of the interval distance according to the number of target objects and the corresponding interval distance, and comparing the number of target objects with the number judgment threshold; if the number of target objects is less than or equal to the number judgment threshold, executing step 1204; if the number of target objects is greater than the number judgment threshold, executing step 1205;

Step 1204, calculating the separation distance according to the target distance between each target object and the optical engine 200;

If the number of target objects is less than or equal to the number judgment threshold, that is, there are fewer environmental influencing factors between the projection surface and the optical machine 200, and the interval data detected by the distance sensor 600 is valid, the interval distance can be calculated based on the target distance between each target object and the optical machine 200.

Step 1205: Calculate a second focus adjustment amount according to the clarity of the projected content image.

If the number of target objects is greater than the quantity judgment threshold, it means that there are many environmental influencing factors between the current projection surface and the optical machine 200, and the effectiveness of the interval distance detected by the distance sensor 600 is low. Therefore, automatic focusing is no longer based on the interval distance, but automatic focusing is performed by detecting the clarity of the projection content image, that is, executing the step of calculating the second focusing amount according to the clarity of the projection content image.

For example, when the controller 500 triggers automatic focusing, the previously measured interval distance information can be sent synchronously, and each measurement contains the following information: the number of objects measured, the target distance of each object (i.e., the distance between the object target and the optical machine 200), and the measurement status of each object. The controller 500 can then judge the results of multiple measurements. In the process of judging the results of multiple measurements, it can first detect whether only one object target is scanned in each scanning process. If only one object target is scanned, the object target is most likely to be the projection surface. Therefore, the average value of the target distance between the target object and the optical machine 200 measured by multiple scans can be calculated as the interval distance for matching the corresponding focal length in the subsequent focusing process. If the number of scanned object targets is large, it means that the current environment is too complex and the distance information is less credible. At this time, the focusing amount can be calculated according to the clarity of the projection content image in the manner provided in the above embodiment to achieve automatic focusing.

In some embodiments, when calculating the interval distance according to the target distance between each target object and the optical machine, the projection device may also traverse the target distance between each target object and the optical machine in the distance detection frame data, and set the distance confidence of the target object according to the target distance, including: if the target distance is within a preset valid interval, setting the distance confidence to a first value; if the target distance is not within the preset valid interval, setting the distance confidence to a second value. Then, the average value of the target distance corresponding to the target object whose distance confidence is the first value is calculated to generate the interval distance.

Regarding the environment between the projection surface and the optical machine 200, since the influence of some object targets on the focusing process can be eliminated directly based on the detected interval distance, in some embodiments, the projection device can also re-judge the scanned object targets and target distances when the distance sensor scans a large number of object targets in the environment, so as to reduce the influence of environmental objects.

For example, in the process of judging multiple measurement results, the controller 500 can judge whether only one object target is measured in each measurement in the scanning result. If not, it is judged whether at most two object targets are measured. If not, it means that the current environment is too complex and the distance information is less reliable. At this time, the minimum valid measurement value can be found from the scanning result data, and the search interval can be set according to the measurement value and the image focusing can be performed.

If only two objects are measured during some measurement processes, it can be determined whether the target distances corresponding to the two objects are within the valid range. If the interval distances corresponding to the two objects are both within the valid range, it is considered that the distance reliability is poor and the projection surface and other objects cannot be distinguished. At this time, the minimum valid value can be extracted and image focusing can be performed in the above manner.

If only two object targets are measured during certain measurement processes, but the minimum distance between the two object targets is not within the valid range, it means that the interval distance comes from the interference value caused by inaccurate calibration data of the distance sensor 600 itself. Therefore, the object target corresponding to the minimum distance can be directly discarded, and the remaining object targets can be regarded as a single object target, and then processed according to the interval distance determination method of only one object target.

If only one object is measured in multiple measurements, the projection device can determine whether the measurement status of each measurement process is valid, such as whether there is empty data or abnormal data in any frame scan data. If the measurement status corresponding to each measurement process is valid, the number of valid measurement status and invalid measurement status is determined. If the number of invalid measurement status is too many, it means that the use environment is too poor and effective distance measurement cannot be completed, so image focusing can be performed.

If only one object target is measured in multiple measurements and all measurement states are valid, determine whether the fluctuation value of the distance measurement value of the object target corresponding to the target during multiple scans is within the measurement accuracy; if it exceeds the measurement accuracy requirement, it means that there may be interference in the previous measurement. Considering the existence of the projection surface, it is impossible to accurately confirm the location of the interference. Therefore, the search interval can be set according to the minimum valid value and image focusing can be performed. If the fluctuation value is within the measurement accuracy, the average value of the target distance is calculated as the interval distance.

If the average value exceeds the set close distance, it means that although the distance measurement is accurate, the deviation of the TOF distance measurement result increases due to the long distance, which may affect the focusing effect. At this time, it is necessary to set a suitable focusing distance and perform image focusing. If the average value is within the set close distance range, perform ranging focusing.

Since in the process of focusing according to the image clarity, it is necessary to capture images in real time to obtain multiple projection content images, and calculate the clarity of the projection content images, this results in a long time-consuming process of focusing according to the image clarity. Therefore, Figure 13 is a schematic diagram of a multi-stage image focusing process in some embodiments. As shown in Figure 13, in order to reduce the time consumption of focusing and ensure the accuracy of the focusing process, in some embodiments, the projection device can focus in stages. For example, the complete focusing process can be divided into three stages, namely, a fuzzy focusing stage, a fine adjustment stage, and a compensation stage. Among them, the fuzzy focusing stage is to quickly find the fine adjustment range, the fine adjustment stage is to find the optimal clarity position, and the compensation stage is used to eliminate the position deviation that may be introduced by parallel control.

Therefore, when searching for the best focus position according to the clarity of the projected content image, the projection device can first sort the focus positions according to the clarity of the projected content image to obtain a clarity sequence, and extract the fine focus interval in the clarity sequence, wherein the focus position corresponding to the projected content image with the highest clarity is within the fine focus interval. For example, when receiving an autofocus instruction, the controller 500 can notify the camera 700 to take a picture, and notify the clarity evaluation unit to do so. After that, the camera takes pictures at a specific frequency to obtain the projected content image. After taking pictures, if a command to read a photo is received from the controller, the path of the most recent photo is given, otherwise it is discarded. The clarity evaluation unit starts to poll whether the container storing the focus position is empty. If it is not empty, the position information is read, and the corresponding picture is read accordingly and the picture clarity is calculated, and then the clarity calculation result is stored in the clarity storage container for standby use.

The controller 500 can read the currently memorized rotation position of the drive motor 320 again, and adjust the movable lens 311 to the adjustment starting position or the adjustment end position according to the principle of proximity. Then drive the drive motor 320 in a specific direction according to a fixed number of steps. When the drive motor 320 drives the lens to a specific position, such as every 100 steps between the adjustment starting position and the adjustment end position as a specific position, the controller 500 can send the current position to the camera and request the camera to return the photo path, and then store the current position in the focus position storage container. When the clarity evaluation unit detects that the above container is not empty, it reads the position information, and performs clarity calculation after obtaining the corresponding photo. At the same time, the drive motor 320 continues to move without waiting for the clarity comparison result.

The above process is repeated until the driving motor 320 drives the movable lens 311 to the adjustment starting position or the adjustment end position. At this time, after the clarity evaluation unit detects that the adjustment starting position or the adjustment end position has been reached, it will sort the clarity of each position and return the best clarity position to the controller 500.

The controller 500 then controls the driving motor 320 to operate according to the returned optimal position and the corresponding number of focusing steps, based on the principle of proximity, so as to drive the lens to move to one side of the fine adjustment interval. For example, after reaching the adjustment end position from the adjustment starting position in the above steps, it is detected that the optimal position is 600 steps away from the near end, and the fine focus interval can be determined to be the position interval between 500 steps and 700 steps away from the near end.

After determining the fine focus interval, the controller 500 may send a second movement instruction to the drive motor 320 to control the optical assembly 310 to move within the fine focus interval according to the preset adjustment step. In order to obtain a fine adjustment effect, after each movement of the optical assembly, the projection device needs to obtain a fine focus image captured from the camera 700, and then calculate the clarity of the fine focus image, and find the focus position corresponding to the fine focus image with the highest clarity according to the clarity of the fine focus image, so as to serve as the best focus position.

For example, after determining that the fine focus interval is a position interval between 500 steps and 700 steps from the near end, the projection device can drive the lens to a position 700 steps from the near end by driving the motor 320, and obtain a fine focus image from the camera 700 every 10 steps, and calculate the clarity of each fine focus image, thereby determining the position corresponding to the image with the highest clarity in the fine focus interval, such as the position 550 steps from the near end as the optimal focus position.

It should be noted that the fine focus interval requires special selection of the end point position involving the focusing stroke, that is, the confirmed best clarity point needs to be processed separately. If the best clarity point is at the end point of the interval, then at this time, only the interval from the end point to 100 steps back is further searched; if the best clarity position is at the starting point of the interval, the drive motor 320 drives the optical component to run to the position 100 steps forward from the starting point, and then the search is performed within this interval.

Since the camera 700 does not take pictures after the motor stops, there is a certain deviation between the actual position of the picture and the position recorded in the controller 500, but the moving pace of the driving motor 320 and the shooting frequency of the camera 700 are fixed, so the above deviation will be limited to a certain range and can be calculated. After the final focus is completed, the position compensation value can be calculated based on the pace of the driving motor 320 and the shooting frequency of the camera 700, and a specific number of steps can be moved before and after the optimal position according to the compensation value, and then the final relative clearest position is obtained in combination with the clarity.

That is, in order to eliminate the deviation, in some embodiments, the projection device can first obtain the moving speed of the drive motor and the shooting frequency of the camera 700 when searching for the best focus position according to the clarity of the projected content image, and then calculate the position compensation value according to the moving speed and the shooting frequency. Then, the focus position corresponding to the projected content image with the highest clarity is extracted to obtain the target focus position, and the target focus position is corrected using the position compensation value to obtain the best focus position.

For example, after the fine focusing process, the best position is 560 steps away from the near end, and according to the step speed of the driving motor 320 and the shooting frequency of the camera 700, the average position compensation value is calculated to be 15 steps. Finally, the projection content images corresponding to the three positions of 545 steps, 560 steps and 575 steps away from the near end are obtained, so as to determine the final clearest point by comparing the clarity.

Since the shooting range of the camera 700 is usually a relatively large area covering the projection surface, when the camera 700 shoots the projection content image, the environmental content outside the projection area will also be included in the captured image. These environmental contents will affect the image processing process, thereby affecting the accurate judgment of the image clarity. To this end, in some embodiments, the projection device can crop the image after acquiring the projection content image to obtain the region of interest (ROI) in the photographed picture to avoid the non-projection part of the picture from affecting the clarity evaluation.

The image can be cropped based on predetermined boundary coordinates, such as the coordinates of the four vertices of the highlight area in the image. Since the projection device sets boundary coordinates for scaling during the trapezoidal correction process to eliminate the influence of oblique transmission, that is, the boundary coordinates can be directly obtained during the trapezoidal correction process, in order to improve the efficiency of image cropping, the projection device can directly use the boundary coordinates generated during the trapezoidal correction process to crop the image.

However, when the position of the projection device moves, the pre-stored boundary coordinates may become invalid. Therefore, FIG. 14 is a schematic diagram of a process of cutting an image in some embodiments. As shown in FIG. 14 , the steps of cutting an image include:

Step 1401, extracting boundary coordinates;

The projection device uses a gravity acceleration sensor, a gyroscope and other attitude sensors to detect whether it has been moved, that is, the attitude sensor is configured to detect the attitude information of the projection device. The projection device can extract the boundary coordinates of the key area when acquiring the projection content image taken by the camera 700 at a preset frequency. The boundary coordinates are the vertex coordinates stored according to the corrected key area when the projection device performs trapezoidal correction.

Step 1402, determine whether the extracted boundary coordinates are within the available period, if so, execute step 1403, otherwise execute step 1404;

Step 1403, read the boundary coordinates and crop the image;

If the storage time of the boundary coordinates is within the available period, that is, the projection device has just undergone keystone correction, the boundary coordinates can be directly used to crop the projection content image.

Step 1404, obtaining posture information and determining whether the projection device is moved, if so, executing step 1405, otherwise executing step 1407;

Step 1405, determining whether the moving distance of the device is within the controllable range, if so, executing step 1403, otherwise executing step 1406;

Step 1406, cutting according to the shape of the highlighted area;

If the storage time of the boundary coordinates is not within the available period, that is, the projection device has been subjected to keystone correction a long time ago, the posture information is obtained through the posture sensor, and the projection content image is cropped according to the posture information.

Among them, when cutting the projected content image according to the posture information, the projection device can compare the current posture information with the original posture information stored in the trapezoidal correction process. If the difference between the current posture information and the original posture information is greater than the posture detection threshold, that is, the projection device has been moved more obviously, it is necessary to redetermine the boundary coordinates, that is, detect the highlight area in the projected content image, and cut the projected content image according to the shape of the highlight area. If the difference between the current posture information and the original posture information is less than or equal to the posture detection threshold, that is, the projection device has not been moved more obviously, the projection device can use the boundary coordinates to cut the projected content image.

For example, during the trapezoidal correction process, the vertex coordinates of the projection area in the photo after the correction is completed will be recorded and saved to a file, and the current projection distance and vertex coordinates will be saved in correspondence. When triggering autofocus, you can determine whether trapezoidal correction has been done in a short time based on the recording time of the boundary coordinates. If so, directly read the four-point coordinates to obtain the ROI area. If it is detected that this is not the first focus after trapezoidal correction, read the device movement information of the gyroscope, that is, whether the device has been detected to have moved since the last trapezoidal correction.

Step 1407, determine whether the current projection distance is within the controllable range, if so, execute step 1405, otherwise execute step 1406.

When the projection device has not been moved, the current projection distance is detected. If the projection distance is within the controllable range, it means that the current usage scenario is very close to the previous one, and the four-point coordinates are directly read to perform image cropping in the ROI area. If the device is detected to be moved but within the controllable range, the projection distance is detected again. If so, the four-point coordinates are read to intercept the ROI area, otherwise the ROI area is intercepted in the conventional way.

In some embodiments, the projection device may also support interference detection during the automatic focusing process, that is, in the process of adjusting the focal length of the optical component, the interval change is detected in real time by the distance sensor. If the interval change exceeds the change threshold, the projection content image is acquired. And based on the graphic feature recognition algorithm, the interference target is identified in the projection content image. When the projection content image contains the interference target, a pause instruction is sent to the drive motor to pause the adjustment of the focal length of the optical component.

For example, after the driving motor drives the lens to the specified position, the camera 700 can be controlled to take pictures, and the position information can be synchronously sent to the clarity sorting unit and the interference monitoring unit. The interference monitoring unit then obtains the picture based on the position information, and analyzes whether there is interference in the process through image comparison; if not, the focusing process is performed normally; if interference occurs, the interference monitoring unit notifies the controller 500 of the interference, and sends the location information of the interference and the information of the interference exit. The controller 500 then makes a decision on whether to refocus based on this information, and displays prompt information to ensure the final focusing effect.

FIG15 is a timing diagram of the automatic focusing method in some embodiments. Based on the above automatic focusing method, in some embodiments of the present application, a projection device is further provided, including: an optical machine 200, a lens 300, a distance sensor 600, a camera 700 and a controller 500, as shown in FIG15. The optical machine is configured to project the playback content onto the projection surface;

The lens 300 includes an optical component and a driving motor; the driving motor is connected to the optical component to adjust the focal length of the optical component; the distance sensor 600 is configured to detect the interval distance between the projection surface and the optical machine; the camera 700 is configured to capture the projection content image; the controller 500 is configured to:

In response to an automatic focusing instruction, acquiring the interval distance;

If the interval distance is less than the interval judgment threshold, calculating a first focus adjustment amount according to the interval distance, and controlling the driving motor to adjust the focal length of the optical component according to the first focus adjustment amount;

If the interval distance is greater than or equal to the interval determination threshold, a second focus adjustment amount is calculated according to the clarity of the projection content image, and the driving motor is controlled to adjust the focal length of the optical component according to the second focus adjustment amount.

The projection device provided in the above embodiment can obtain the interval distance between the optical machine and the projection surface through the distance sensor after receiving the automatic focusing instruction. Then determine the current application scene according to the interval distance. If the interval distance is less than the interval judgment threshold, the current application scene is determined to be a close-distance scene, so the first focusing amount can be calculated according to the interval distance; if the interval distance is greater than or equal to the interval judgment threshold, the current application scene is determined to be a long-distance scene, so the second focusing amount can be calculated according to the clarity of the projected content image, and finally control the drive motor to adjust the focal length of the optical component according to the first focusing amount or the second focusing amount. The projection device can automatically focus according to different data according to different application scenarios, and can quickly adjust the optical component to the optimal focal length state, improve the clarity of the projection picture, and shorten the time consumed by the focusing process.

In some embodiments, the projection device provided by the present application can realize an anti-eye-shot function. In order to prevent the user from accidentally entering the laser trajectory range of the projection device and causing the risk of visual damage, when the user enters the preset specific non-safe area where the projection device is located, the controller can control the user interface to display corresponding prompt information to remind the user to leave the current area. The controller can also control the user interface to reduce the display brightness to prevent the laser from causing damage to the user's eyesight.

In some embodiments, when the projection device is configured as a children's viewing mode, the controller will automatically turn on the anti-eye-shot switch.

In some embodiments, after the controller receives the position movement data sent by the gyroscope sensor, or receives the foreign object intrusion data collected by other sensors, the controller controls the projection device to turn on the anti-eye switch.

In some embodiments, when the data collected by a time-of-flight (TOF) sensor, camera device, or other device triggers any preset threshold condition, the controller will control the user interface to reduce the display brightness, display prompt information, and reduce the optical machine transmission power, brightness, and intensity to protect the user's eyesight.

In some embodiments, the projection device controller may control the correction service to send a signal to the time-of-flight sensor to query the current device status of the projection device, and then the controller receives data feedback from the time-of-flight sensor.

The correction service can send a notification to the process communication framework (HSP Core) to notify the algorithm service to start the anti-eye-shooting process signaling; the process communication framework (HSP Core) will call the service capability from the algorithm library to call the corresponding algorithm service, for example, it may include a photo detection algorithm, a screenshot algorithm, and a foreign object detection algorithm;

The process communication framework (HSP Core) returns the foreign body detection results to the correction service based on the above algorithm service; for the returned results, if the preset threshold conditions are met, the controller will control the user interface to display prompt information and reduce the display brightness. The signaling timing is shown in Figure 16.

In some embodiments, when the anti-eye-glare switch of the projection device is turned on, when the user enters a preset specific area, the projection device will automatically reduce the intensity of the laser emitted by the optical machine, reduce the brightness of the user interface display, and display safety prompts.

The control of the above-mentioned anti-eye function of the projection device can be achieved by the following methods:

The controller uses an edge detection algorithm to identify the projection area of the projection device based on the projection content image obtained by the camera; when the projection area is displayed as a rectangle or a quasi-rectangle, the controller obtains the coordinate values of the four vertices of the above rectangular projection area through a preset algorithm;

When realizing foreign object detection in the projection area, the perspective transformation method can be used to correct the projection area into a rectangle, and the difference between the rectangle and the projection screenshot can be calculated to determine whether there is a foreign object in the display area; if the judgment result is that there is a foreign object, the projection device automatically triggers the anti-shooting eye function to start.

When realizing foreign object detection in a certain area outside the projection area, the camera content of the current frame and the camera content of the previous frame can be subtracted to determine whether there is a foreign object entering the area outside the projection area; if it is determined that a foreign object has entered, the projection device automatically triggers the anti-shooting eye function.

At the same time, the projection device can also use a time-of-flight (ToF) camera or a time-of-flight sensor to detect real-time depth changes in a specific area; if the depth value changes exceed a preset threshold, the projection device will automatically trigger the anti-glare function.

In some embodiments, as shown in FIG21 , a schematic diagram of a process of implementing an anti-eye-shooting algorithm by a projection device is provided. The projection device determines whether to enable the anti-eye-shooting function based on the collected flight time data, screenshot data, and camera data analysis. There are three ways for the projection device to implement the anti-eye-shooting algorithm:

Method 1:

Step 2100-1, collecting time-of-flight (TOF) data;

Step 2100-2, performing depth difference analysis based on the collected flight time data;

Step 2100-3, determining whether the depth difference is greater than a preset threshold value X. If the depth difference is greater than the preset threshold value X, and X is 0, executing step 2103;

Step 2103, the screen becomes dark and a prompt pops up.

If the depth difference is greater than a preset threshold value X, when the preset threshold value X is implemented as 0, it can be determined that a foreign object is in a specific area of the projection device. If the user is in the specific area and his vision is at risk of being damaged by the laser, the projection device will automatically activate the anti-eye function to reduce the intensity of the laser emitted by the optical machine, reduce the brightness of the user interface display, and display a safety prompt message.

Method 2:

Step 2101-1, collecting screenshot data;

Step 2101-2, performing additive color mode (RGB) difference analysis based on the collected screenshot data;

Step 2101-3, determine whether the RGB difference is greater than a preset threshold value Y. If the RGB difference is greater than the preset threshold value Y, execute step 2103;

Step 2103, the screen becomes dark and a prompt pops up.

The projection device performs a color addition mode (RGB) difference analysis based on the collected screenshot data. If the color addition mode difference is greater than the preset threshold Y, it can be determined that a foreign object is in a specific area of the projection device. If there is a user in the specific area, his or her eyesight is at risk of being damaged by the laser. The projection device will automatically activate the anti-eye function, reduce the intensity of the emitted laser, reduce the brightness of the user interface display, and display the corresponding safety prompt information.

Method 3:

Step 2102-1, collecting camera data;

Step 2102-2, obtaining projection coordinates according to the collected camera data, if the obtained projection coordinates are in the projection area, executing step 2101-3, if the obtained projection coordinates are in the extension area, still executing step 2101-3;

Step 2102-3, performing additive color mode (RGB) difference analysis based on the collected camera data;

Step 2102 - 4 , determining whether the RGB difference is greater than a preset threshold value Y. If the RGB difference is greater than the preset threshold value Y, executing step 2103 .

Step 2103, the screen becomes dark and a prompt pops up.

The projection device obtains the projection coordinates according to the collected camera data, and then determines the projection area of the projection device according to the projection coordinates, and further performs additive color mode (RGB) difference analysis in the projection area. If the color additive mode difference is greater than the preset threshold value Y, it can be determined that a foreign object is in a specific area of the projection device. If there is a user in the specific area, his or her vision is at risk of being damaged by the laser. The projection device will automatically start the anti-eye function, reduce the intensity of the emitted laser, reduce the brightness of the user interface display, and display the corresponding safety prompt information.

If the acquired projection coordinates are in the extended area, the controller can still perform additive color mode (RGB) difference analysis in the extended area; if the color additive mode difference is greater than the preset threshold value Y, it can be determined that a foreign object is in a specific area of the projection device. If there is a user in the specific area, his eyesight is at risk of being damaged by the laser emitted by the projection device. The projection device will automatically activate the anti-eye function, reduce the intensity of the emitted laser, reduce the brightness of the user interface display, and display corresponding safety prompt information.

FIG. 17 is a schematic diagram of the signaling interaction timing of a projection device implementing a display picture correction function according to another embodiment of the present application.

In some embodiments, the projection device can monitor the movement of the device through a gyroscope or a gyroscope sensor. The calibration service sends a signal to the gyroscope to query the device status and receives a signal from the gyroscope to determine whether the device has moved.

In some embodiments, the display correction strategy of the projection device can be configured as follows: when changes occur in the gyroscope and the time-of-flight sensor at the same time, the projection device prioritizes triggering trapezoidal correction; after the gyroscope data is stable for a preset length of time, the controller starts triggering the trapezoidal correction; and the controller can also configure the projection device to not respond to instructions issued by the remote control buttons while trapezoidal correction is in progress; in order to cooperate with the implementation of trapezoidal correction, the projection device will display a pure white picture card.

Among them, the trapezoidal correction algorithm can construct the transformation matrix between the projection surface and the optomechanical coordinate system in the world coordinate system based on the binocular camera; further combine the optomechanical internal parameters to calculate the homography between the projection screen and the playback card, and use the homography to realize arbitrary shape transformation between the projection screen and the playback card.

In some embodiments, the correction service sends a signaling to the process communication framework (HSP CORE) for notifying the algorithm service to start the trapezoidal correction process, and the process communication framework further sends a service capability call signaling to the algorithm service to obtain the algorithm corresponding to the capability;

The algorithm service obtains the execution of the photo taking and image algorithm processing service, and the obstacle avoidance algorithm service, and sends them to the process communication framework in the form of signaling; in some embodiments, the process communication framework executes the above algorithm and feeds back the execution result to the correction service, and the execution result may include successful photo taking and successful obstacle avoidance.

In some embodiments, when the projection device executes the above algorithm or transmits data, if an error occurs, the correction service will control the user interface to display an error return prompt, and control the user interface to display the keystone correction and autofocus chart again.

Through the automatic obstacle avoidance algorithm, the projection device can identify the screen; and use the projection changes to correct the projected image to display inside the screen, achieving the effect of alignment with the edge of the screen.

Through the autofocus algorithm, the projection device can use the time-of-flight (ToF) sensor to obtain the distance between the optical machine and the projection surface, search for the optimal image distance in a preset mapping table based on the distance, and use the image algorithm to evaluate the clarity of the projected picture, thereby fine-tuning the image distance.

In some embodiments, the automatic trapezoidal correction signaling sent by the correction service to the process communication framework may include other function configuration instructions, such as control instructions such as whether to implement synchronous obstacle avoidance and whether to enter the screen.

The process communication framework sends a service capability call signal to the algorithm service, so that the algorithm service obtains and executes the autofocus algorithm to adjust the viewing distance between the device and the screen. In some embodiments, after applying the autofocus algorithm to implement the corresponding function, the algorithm service can also obtain and execute the automatic screen entry algorithm, and the process may include a trapezoidal correction algorithm.

In some embodiments, the projection device automatically enters the screen, and the algorithm service can set the 8-position coordinates between the projection device and the screen; then the autofocus algorithm is used again to adjust the viewing distance between the projection device and the screen; finally, the correction result is fed back to the correction service, and the user interface is controlled to display the correction result, as shown in Figure 17.

In some embodiments, the projection device uses an autofocus algorithm and its configured laser ranging to obtain the current object distance to calculate the initial focal length and the search range; then the projection device drives the camera to take pictures and uses the corresponding algorithm to evaluate the clarity.

The projection device searches for the best possible focal length within the above search range based on the search algorithm, and then repeats the above steps of taking pictures and evaluating clarity, and finally finds the optimal focal length through clarity comparison to complete automatic focusing.

For example, after the projection device is started, the steps of implementing the auto-focus algorithm are shown in FIG. 18 , including the following steps:

Step 1801: The user moves the device, and the projection device automatically completes the calibration and refocuses;

Step 1802, the controller will detect whether the auto focus function is turned on, if not, the controller will end the auto focus service, if yes, then execute step 1803;

Step 1803, the middleware obtains the detection distance of the time of flight (TOF);

When the autofocus function is turned on, the projection device will obtain the detection distance of the time-of-flight (TOF) sensor through the middleware for calculation.

Step 1804, obtaining an approximate focal length by querying a mapping table according to the distance;

Step 1805, the middleware sets the focal length to the optical engine;

The controller queries a preset mapping table according to the acquired distance to obtain the approximate focal length of the projection device; then the middleware sets the acquired focal length to the optical machine of the projection device.

Step 1806, the camera takes a photo;

Step 1807, judging whether the focusing is completed according to the evaluation function, if so, the automatic focusing process ends, otherwise, executing step 1808;

Step 1808, the middleware fine-tunes the focal length (step length) and executes step 1805 again.

After the optical machine emits laser light at the above focal length, the camera will execute the photo command; the controller determines whether the focus of the projection device is completed based on the obtained photo results and the evaluation function; if the judgment result meets the preset completion condition, the automatic focus process is controlled to end;

If the judgment result does not meet the preset completion conditions, the middleware will fine-tune the focal length parameters of the projection equipment optical machine. For example, the focal length can be gradually fine-tuned by preset steps, and the adjusted focal length parameters can be set to the optical machine again; thereby achieving repeated photo taking and clarity evaluation steps, and finally finding the optimal focal length through clarity comparison to complete automatic focus.

In some embodiments, the projection device provided in the present application can implement a display correction function through a trapezoidal correction algorithm.

First, based on the calibration algorithm, two sets of external parameters between the two cameras and between the camera and the optical machine, namely the rotation and translation matrices, can be obtained; then, a specific chessboard image card is played through the optical machine of the projection device, and the depth value of the projected chessboard corner point is calculated, for example, the xyz coordinate value is solved through the translation relationship between the binocular cameras and the principle of similar triangles; then, the projection surface is fitted based on the xyz, and its rotation and translation relationships with the camera coordinate system are obtained, which may specifically include the pitch relationship (Pitch) and the yaw relationship (Yaw).

The roll parameter value can be obtained through the gyroscope configured in the projection device to combine the complete rotation matrix, and finally the external parameters of the projection surface to the optomechanical coordinate system in the world coordinate system are calculated.

Combining the R and T values of the camera and optomechanical machine obtained in the above steps, the transformation relationship between the world coordinate system of the projection surface and the optomechanical coordinate system can be obtained; combined with the optomechanical internal parameters, the homography matrix from the point of the projection surface to the optomechanical map point can be formed.

Finally, a rectangle is selected on the projection surface, and the coordinates corresponding to the optical machine chart are inverted using homography. These coordinates are the correction coordinates, and by setting them to the optical machine, trapezoidal correction can be achieved.

As shown in FIG19 , a schematic diagram of a process for implementing a trapezoidal correction and obstacle avoidance algorithm for a projection device is provided, including the following steps:

Step 1901, the projection device controller obtains the depth value of the point corresponding to the pixel point of the photo, or the coordinates of the projection point in the camera coordinate system;

Step 1902, the middleware obtains the relationship between the optical-mechanical coordinate system and the camera coordinate system through the depth value;

Step 1903, the controller then calculates the coordinate value of the projection point in the optical-mechanical coordinate system;

Step 1904, fitting the plane based on the coordinate values to obtain the angle between the projection plane and the optical machine;

Step 1905, obtaining the corresponding coordinates of the projection point in the world coordinate system of the projection surface according to the angle relationship;

Step 1906, a homography matrix may be calculated based on the coordinates of the chart in the optical-mechanical coordinate system and the coordinates of the corresponding points on the projection plane;

Step 1907, the controller determines whether there is an obstacle based on the acquired data, and if so, executes step 1908, otherwise, executes step 1909;

Step 1908, randomly select rectangular coordinates on the projection surface in the world coordinate system, and calculate the area to be projected by the optical machine according to the homography relationship;

Step 1909, when there is no obstacle, the controller can obtain the QR code feature points;

Step 1910, obtaining the coordinates of the QR code on the pre-made map card;

Step 1911, obtaining the homography relationship between the camera photo and the drawing card;

Step 1912, converting the obtained obstacle coordinates into a map card to obtain the obstacle occlusion map card coordinates;

Step 1913, according to the coordinates of the blocked area of the obstacle map in the optical-mechanical coordinate system, the coordinates of the blocked area of the projection surface are obtained by homography matrix transformation;

Step 1914, randomly select rectangular coordinates on the projection surface in the world coordinate system while avoiding obstacles, and calculate the area to be projected by the optical machine based on the homography relationship.

It can be understood that when the obstacle avoidance algorithm selects the rectangle step in the trapezoidal correction algorithm process, the algorithm (OpenCV) library is used to complete the foreign body contour extraction, and the obstacle is avoided when the rectangle is selected to realize the projection obstacle avoidance function.

In some embodiments, as shown in FIG. 20 , a flowchart of implementing an entry algorithm for a projection device includes the following steps:

Step 2001, the middleware obtains the QR code card captured by the camera;

Step 2002, identifying the feature points of the QR code and obtaining the coordinates in the camera coordinate system;

Step 2003, the controller further obtains the coordinates of the preset image card in the optical-mechanical coordinate system;

Step 2004, solving the homography relationship between the camera plane and the optomechanical plane;

Step 2005, the controller identifies the coordinates of the four vertices of the curtain captured by the camera based on the homography relationship;

Step 2006, obtaining the range of the image card to be projected onto the screen light machine according to the homography matrix.

It can be understood that in some embodiments, the screen entry algorithm is based on the algorithm library (OpenCV), which can identify and extract the largest black closed rectangular outline to determine whether it is a 16:9 size; project a specific image card and use a camera to take a photo, extract multiple corner points in the photo to calculate the homography of the projection surface (screen) and the optical machine playback image card, convert the four vertices of the screen to the optical machine pixel coordinate system through the homography, and convert the optical machine image card to the four vertices of the screen to complete the calculation and comparison.

The telephoto micro-projector TV has the characteristic of flexible movement. The projected image may be distorted after each displacement. In addition, if there are foreign objects blocking the projection surface or the projection image is abnormal from the screen, the projection device provided in this application and the display control method based on geometric correction can automatically complete the correction for the above problems, including automatic trapezoidal correction, automatic screen entry, automatic obstacle avoidance, automatic focus, anti-eye shooting and other functions.

The display control method provided in some embodiments of the present application can also be used to automatically adjust screen brightness. The method for automatically adjusting brightness can be applied to a projection device. In order to meet the implementation of the method for automatically adjusting brightness, the present application provides a projection device for automatically adjusting screen brightness, including a projection screen 1 and a device for projection 2, wherein the device for projection 2 includes a controller 500;

The controller 500 is configured to: determine a plurality of screen partitions, and obtain a grayscale parameter of each screen partition within a target time length;

Determine a target screen partition from the plurality of screen partitions according to the grayscale parameters of each screen partition, the target screen partition being a screen partition whose grayscale parameters are within a target grayscale range within a target time length;

Determine the target white balance parameters according to the grayscale parameters of the target screen partition;

Adjust the screen brightness based on the screen's white balance parameters.

The above-mentioned projection screen 1 realizes brightness adjustment by partitioning the screen, thereby improving the efficiency of screen brightness adjustment, and monitors the brightness of the screen within the target time to realize timely brightness adjustment, thereby preventing the projection screen 1 from burning in and improving the display effect of the picture.

In some embodiments, the projection screen 1 further comprises an ambient light sensor, and the ambient light sensor is configured to: detect ambient light parameters;

The controller 500 is configured to: obtain ambient light parameters detected by the ambient light sensor;

The target white balance parameters are determined according to the grayscale parameters of the target screen partition and the ambient light parameters.

The projection screen 1 takes into account the influence of ambient light and needs to adjust the screen brightness in time when the ambient light changes to adapt to the current environment, thereby ensuring that the screen is visible in a brighter environment while reducing the screen brightness to prevent screen burn-in.

As shown in FIG. 22, FIG. 22 is a schematic diagram of an application scenario of a screen brightness adjustment method provided by an embodiment of the present application, and FIG. 22 includes a projection screen 1. For ease of explanation, a brightness control 204 for adjusting white balance parameters is displayed on the projection screen 1 in the figure, and the brightness control 204 is used to display the brightness of the current screen, that is, the white balance parameter. The white balance parameter of the projection screen 1 corresponding to (a) in FIG. 22 is 80%, indicating that the screen brightness is in a high brightness state. Being in a high brightness state for a long time will damage the screen, so the brightness needs to be reduced. The present disclosure divides the screen of the projection screen 1 into multiple screen partitions, obtains the grayscale parameters of each screen partition within a target duration, and then determines the target screen partition from the multiple screen partitions according to the grayscale parameters of each screen partition. The target screen partition is a screen partition whose grayscale parameters are continuously in the target grayscale range within the target duration; further, the target white balance parameter is determined according to the grayscale parameter corresponding to the target screen partition, and finally the screen brightness is adjusted according to the white balance parameter. As shown in FIG. 22 (b), the white balance parameter is adjusted from 80% to 60%, then the brightness of the current screen is in a safe state, and the screen brightness is reduced. The brightness is adjusted by partitioning the screen, which improves the efficiency of screen brightness adjustment. The brightness of the screen within the target time is monitored to adjust the brightness in time, thereby preventing the projection screen 1 from burning in and improving the display effect of the picture.

As shown in FIG. 23 , FIG. 23 is a schematic diagram of an application scenario of a screen brightness adjustment method provided by an embodiment of the present application, and FIG. 23 includes a projection screen 1. For ease of explanation, a control 204 for adjusting white balance parameters is displayed on the projection screen 1 in the figure, and the brightness control is used to display the brightness of the current screen, that is, the white balance parameter. The white balance parameter of the projection screen 1 corresponding to (a) in FIG. 22 is 40%, indicating that the screen brightness is in a low brightness state, and the historical white balance parameter of the screen is detected to determine that the historical white balance parameter is 60%. The present disclosure divides the screen of the projection screen 1 into multiple screen partitions, obtains the grayscale parameters of each screen partition within a target duration, and then determines the target screen partition from the multiple screen partitions according to the grayscale parameters of each screen partition. The target screen partition is a screen partition whose grayscale parameters are continuously in the target grayscale range within the target duration; further, the target white balance parameter is determined according to the grayscale parameter corresponding to the target screen partition, and finally the screen brightness is adjusted according to the white balance parameter. As shown in Figure 22 (b), the white balance parameter is adjusted from 40% to 60%, and the current screen brightness is in a safe state, and the screen brightness is improved, ensuring a good viewing experience for users. The brightness is adjusted by partitioning the screen, which improves the efficiency of screen brightness adjustment, and the brightness of the screen is monitored within the target time to adjust the brightness in time, thereby preventing the projection screen 1 from burning in and improving the display effect of the picture.

It should be noted that the screen brightness adjustment method provided by the present disclosure can be a non-sensing adjustment, that is, the control 204 for adjusting the white balance parameter is not displayed on the projection screen 1, and the brightness change is processed in the background of the projection device. In order to facilitate the description of the result of adjusting the brightness, the brightness control is still used for explanation.

The display control method provided in the embodiment of the present application can be implemented by a computer device when used to implement screen brightness adjustment. The computer device includes but is not limited to a server, a personal computer, a laptop computer, a tablet computer, a smart TV, a vehicle-mounted device, etc.

As shown in FIG. 24 , FIG. 24 is a flow chart of a screen brightness adjustment method provided in an embodiment of the present application. The method can be performed by a screen brightness adjustment device, wherein the device can be implemented by software and/or hardware and can generally be integrated in an electronic device, such as the above-mentioned projection device. As shown in FIG. 24 , the method mainly includes the following steps 2401 to 2404:

Step 2401, determine a plurality of screen partitions, and obtain the grayscale parameters of each screen partition within a target time length.

Among them, the grayscale parameter is the average grayscale value of the pixels of each screen partition, or the maximum grayscale value of all pixels, or the mean square grayscale value of all pixels. In the embodiment of the present application, the method of calculating the average grayscale value has better anti-interference than the method of taking the maximum value, and has higher efficiency than the root mean square method. In some embodiments, the method of calculating the average grayscale value is selected. It can be understood that the grayscale parameter is the grayscale known to those skilled in the art. The grayscale is to divide the brightness change between the brightest and the darkest into several parts to facilitate the screen brightness control corresponding to the signal input.

The target duration is determined according to the type of content to be displayed in multiple screen partitions, and the target duration is different for different types of content to be displayed. The type of content to be displayed refers to the brightness dynamic range, which includes but is not limited to: standard dynamic range (Standard Dynamic Range, SDR), high dynamic range (High-Dynamic Range, HDR). For example, if the type of content to be displayed is SDR, the target duration is 5 minutes; if the type of content to be displayed is HDR, the target duration is 1 minute. The above-mentioned values set for the target duration are only exemplary, and the present disclosure does not limit this.

An implementation method is provided in an embodiment of the present application, which detects grayscale parameters of multiple screen partitions according to a preset time, and obtains grayscale parameters of the multiple screen partitions within a target time length when the number reaches a preset threshold.

The preset time is 5s, the preset threshold is 60, and the target duration is 5 minutes. The grayscale parameters of multiple screen partitions are detected once every 5s until the number of detections reaches 60 times, and the grayscale parameters of multiple screen partitions within 5 minutes are obtained.

Among them, SDR images do not have more comprehensive details and do not have a wider color range. When the image is overexposed, the information of the brighter part of the image will be lost; similarly, when the image is underexposed, the information of the darker part of the image will also be lost. HDR can provide more color range and image details, improve the image contrast, what you see is what you get, greatly restore the real environment, and present extremely high image quality. Setting different target durations for different brightness dynamic ranges can more accurately detect screen partitions that are at high brightness and prone to burn-in.

The following describes the process of determining multiple screen partitions:

As shown in Figure 25, Figure 25 is a schematic diagram of multiple screen partitions provided in an embodiment of the present application. The screen is divided into 3 rows and 3 columns to obtain 9 screen partitions, namely S1, S2, S3, S4, S5, S6, S7, S8, and S9.

As shown in Figure 26, Figure 26 is a second schematic diagram of multiple screen partitions provided in an embodiment of the present application. Another implementation method is provided in an embodiment of the present application. First, the central area of the screen is determined, and then the area outside the center is divided to determine multiple screen partitions. In Figure 26, the central area C1 is first determined, and then the area outside the central area C1 is divided into C2, C3, C4, and C5, and 5 screen partitions are determined: C1, C2, C3, C4, and C5. It should be emphasized that the present disclosure does not make specific restrictions on the way of dividing the screen, and the above Figures 25 and 26 are only exemplary.

In some embodiments, the projection device can determine multiple screen partitions based on user input to meet the diverse needs of users. An implementation method is provided in an embodiment of the present application. First, a parameter input by the user is obtained. The parameter can be the number of screen partitions or the area value of each screen partition. Then, multiple screen partitions are determined based on the parameters input by the user. For example, the resolution of projection screen 1 is 3840×2160, and the parameter input by the user is the number of screen partitions: 2304, then 2304 screen partitions are determined. For another example, the parameter input by the user is the area value of each screen partition: 64×36, then 2304 screen partitions are determined.

In some embodiments, after determining multiple screen partitions, the grayscale parameters of each screen partition within the target duration are obtained. Each screen partition contains a certain number of pixels, and the screen partition is calculated as a whole to avoid calculating the grayscale parameters of a large number of pixels at one time, thereby reducing the processing burden of the projection device controller. An implementation method is provided in the embodiment of the present application, first obtaining the grayscale parameters of all pixels in each screen partition, and then averaging them to obtain the grayscale parameters of each screen partition.

The above embodiment divides the screen into a plurality of screen partitions. Calculating the screen as a whole can reduce the amount of calculation and the processing burden of the projection device controller, thereby more accurately adjusting the brightness of the screen.

Step 2402 : determining a target screen partition from a plurality of screen partitions according to the grayscale parameters of each screen partition.

The target screen partition is a screen partition whose grayscale parameter is within the target grayscale range within the target duration. It is understandable that the number of target screen partitions may be one or more, and the present disclosure does not limit this.

As mentioned above, the target duration is determined according to the type of content to be displayed, and accordingly, the target grayscale range is also determined according to the type of content to be displayed. For example, if the type of content to be displayed is SDR, the target grayscale range is greater than or equal to 90%; if the type of content to be displayed is HDR, the target grayscale range is greater than or equal to 80%.

An implementation method is provided in the embodiment of the present application, which detects the grayscale parameters of multiple screen partitions according to a preset time. When the grayscale parameters are within the target grayscale range, a counter is incremented by one. When the counter accumulates to a preset number of times, the screen partition is determined to be a target screen partition.

The preset time is 5s, the preset number of times is 60, and the target duration is 5 minutes. The grayscale parameters of multiple screen partitions are detected once every 5s. When the grayscale parameters of the screen partition are detected to be greater than or equal to 90%, the counter is incremented by one. When the counter accumulates to 60 times, it means that the grayscale parameters of the screen partition are continuously greater than or equal to 90% within 5 minutes, and there is a possibility of screen burn-in. The screen partition is determined as the target screen partition.

Normally, the grayscale parameters of each pixel on the projection screen of the projection device change continuously. The embodiment provided in the present disclosure processes the screen partitions whose grayscale parameters change within the target grayscale range within the target time length, thereby achieving comprehensive detection of the screen brightness, thereby accurately determining the screen partitions with high brightness and the possibility of burn-in.

As shown in FIG. 27 , FIG. 27 is a schematic diagram of a target screen partition provided by an embodiment of the present application. The target grayscale range is greater than or equal to 90%. The grayscale parameter of screen partition S5 changes from 91% to 93% and then to 92% within the target duration. It can be seen that the grayscale parameter of screen partition S5 is continuously within the target grayscale range within the target duration, and screen partition S5 can be determined as the target screen partition. However, the grayscale parameter of screen partition S9 changes from 94% to 90% and then to 83% within the target duration, so screen partition S9 is not the target screen partition.

In some embodiments, different grayscale ranges are set according to the grayscale parameters of each screen partition, so as to more precisely determine the target screen partition. First, screen partitions with grayscale parameters greater than a second preset grayscale threshold are selected from multiple screen partitions. For example, if the second preset grayscale threshold is 60%, A screen partitions with grayscale parameters greater than 60% are determined from the multiple screen partitions.

Normally, screen burn-in may occur when the grayscale parameter of the screen is greater than the second preset grayscale threshold. Through the above implementation, screen partitions with grayscale parameters less than or equal to the second preset grayscale threshold are removed. These screen partitions are within a safe range of brightness and do not need to reduce the brightness, thereby reducing unnecessary calculations and improving the processing efficiency of the projection device controller.

As shown in Figure 28, Figure 28 is a schematic diagram of the target screen partition provided by the embodiment of the present application. In Figure 28, the second preset grayscale threshold is 60%, the grayscale range of screen partition C1 is 90% to 95%, the grayscale range of screen partition C2 is 85% to 90%, the grayscale range of screen partition C3 is 50% to 60%, the grayscale range of screen partition C4 is 85% to 90%, and the grayscale range of screen partition C5 is 50% to 60%. According to the second preset grayscale threshold of 60%, it is determined that screen partitions C3 and C5 are in a safe range of brightness and there is no need to reduce the brightness. Further, according to the target grayscale range being greater than or equal to 90%, the target screen partition is determined from screen partitions C1, C2, and C4, and the target screen partition is obtained as C1.

In some embodiments, the target grayscale range includes a first grayscale range and a second grayscale range, wherein the first grayscale range is a range greater than a first preset grayscale threshold and less than a second preset grayscale threshold; the second grayscale range is a range greater than or equal to the second preset grayscale threshold. For example, if the first preset grayscale threshold is 60% and the second preset grayscale threshold is 80%, the target grayscale range includes grayscale ranges of two stages: 60%-80% and greater than 80%.

As shown in Figure 29, Figure 29 is a schematic diagram of the target screen partition provided by the embodiment of the present application. As shown in Table 1, Table 1 shows the grayscale parameters of each screen partition in Figure 29.

Screen partition Grayscale parameters S1 70%～75% S2 80%～85% S3 70%～75% S4 80%～85% S5 90%～95% S6 80%～85% S7 70%～75% S8 80%～85% S9 70%～75%

Table 1

Since the target grayscale range includes two stages of grayscale ranges: 60%-80% and greater than 80%, according to the grayscale parameters of screen partitions S1, S2, S3, S4, S5, S6, S7, S8, S9 in Figure 29 shown in Table 1, it is determined that the grayscale parameters of screen partitions S1, S2, S3, S4, S5, S6, S7, S8, S9 are all target screen partitions, and if the grayscale parameters of screen partitions S2, S4, S5, S6, S8 are greater than 80%, they are the target screen partitions of the second grayscale range, and if the grayscale parameters of screen partitions S1, S3, S7, S9 are within 60%-80%, they are the target screen partitions of the first grayscale range.

The following describes the classification of target screen partitions:

A. Target screen partition 1

The target screen partition 1 is a screen partition whose grayscale parameters are continuously in the first grayscale range within the target time duration, for example, the above-mentioned screen partitions S1, S3, S7, and S9.

B. Target screen partition 2

The target screen partition 2 is a screen partition whose grayscale parameters are continuously in the second grayscale range within the target time duration, for example, the above-mentioned screen partitions S2, S4, S5, S6, and S8.

a. The screen partition whose grayscale parameters are continuously within the target sub-grayscale range within the target duration.

In some embodiments, the second grayscale range includes at least two sub-grayscale ranges, and the target screen partition includes m screen partitions, where m is a positive integer greater than 2. From the m screen partitions, a first screen partition is determined, and the first screen partition is a screen partition in the m screen partitions that is in the target sub-grayscale range. The number of screen partitions whose grayscale parameters are in the target sub-grayscale range is greater than the number of screen partitions in other sub-grayscale ranges, and the other sub-grayscale ranges are sub-grayscale ranges other than the target sub-grayscale range within at least two sub-grayscale ranges.

As shown in Table 1, the second grayscale range includes at least two sub-grayscale ranges of 90% to 95% and 80% to 85%, and the target screen partitions include S2, S4, S5, S6, and S8. The first screen partitions S2, S4, S6, and S8 are determined from the five target screen partitions. The grayscale parameters of the first screen partitions S2, S4, S6, and S8 are all between 80% and 85%, and 80% to 85% can be determined as the target sub-grayscale range. It can be understood that the first screen partition in the target sub-grayscale range of 80% to 85% is the screen partition with the largest number among the five target screen partitions. The target white balance parameters are determined according to the first screen partition with the largest number and the second grayscale range, thereby ensuring the uniformity of the screen brightness.

b. The grayscale parameters are continuously in the second grayscale range within the target duration, and the number ratio is greater than the preset number ratio of the screen partitions. For example, the preset number ratio is 60%, the second grayscale range is 80% to 85%, the grayscale parameters of S2, S4, S6, and S8 in the screen partitions S2, S4, S5, S6, and S8 are all between 80% and 85%, and the grayscale parameters of 4 of the 5 screen partitions are in the second grayscale range, accounting for 80%, which is greater than the preset number ratio of 60%, and the target screen partitions are determined to be screen partitions S2, S4, S6, and S8.

c. Within the target duration, the grayscale parameters are continuously in the second grayscale range and the screen partition with the highest grayscale parameters. For example, among the screen partitions S2, S4, S5, S6, and S8, the grayscale parameters of S2, S4, S6, and S8 are all between 80% and 85%, and the grayscale parameter of the screen partition S5 is between 90% and 95%, then the screen partition S5 is determined as the target screen partition.

In the above embodiment, the target screen partition is refined, so that a more accurate white balance parameter that meets the brightness adjustment requirement is subsequently determined according to the target screen partition.

Step 2403, determining target white balance parameters according to the grayscale parameters of the target screen partition.

The white balance parameter is white balance known to those skilled in the art, and white balance is an indicator that describes the accuracy of white generated by mixing the three primary colors of red, green and blue in the projection screen 1 .

In some embodiments, if the target screen partition is a screen partition whose target grayscale range is determined according to the type of content to be displayed, the target white balance parameter is determined according to the grayscale parameter of the target screen partition.

As mentioned above, when the type of content to be displayed is SDR, the target screen partition is a screen partition with a grayscale range greater than or equal to 90%, then the target white balance parameter can be determined as 80% of the current white balance parameter based on the grayscale parameter of 91% of the target screen partition; when the type of content to be displayed is HDR, the target screen partition is a screen partition with a grayscale range greater than or equal to 80%, then the target white balance parameter can be determined as 70% of the current white balance parameter based on the grayscale parameter of 91% of the target screen partition.

In actual applications, the usage conditions of each screen partition of the display device screen are different. Even at the same time, the grayscale parameters of each screen partition are also different, resulting in different aging degrees of the screen partitions, which is prone to screen burn-in. In order to extend the service life of the screen, the target white balance parameters can be determined based on the grayscale parameters of the screen partition with the highest frequency of use or the most serious aging degree.

Among them, the location information of each screen partition can represent its aging degree. For example, under normal circumstances, the aging degree of the center of the screen is higher, the aging degree of the screen partition close to the center is second, and the aging degree of the edge of the screen is the lowest. The historical display time of each screen partition can represent its usage frequency. The historical display time is the historical time that each screen partition is in the target grayscale range. It can be understood that the longer the historical display time is, the longer the screen partition is in a high brightness state and the higher the usage frequency.

In some embodiments, a weight coefficient of each screen partition is determined based on the position information of the plurality of screen partitions. The weight coefficient is positively correlated with the position information of the screen partition. The closer the position information of the screen partition is to the central area, the larger the weight coefficient is, indicating that the aging degree of the screen partition is higher.

Taking FIG. 26 as an example, the weight coefficient of each screen partition is determined according to the position information of multiple screen partitions, and the weight coefficient of screen partition C1 is greater than that of screen partitions C2, C3, C4, and C5.

In some embodiments, the weight coefficient of each screen partition is determined according to the historical display time of multiple screen partitions. The weight coefficient is positively correlated with the historical display time. The greater the historical display time, the greater the weight coefficient, indicating that the aging degree of the screen partition is higher.

Taking FIG. 26 as an example, the historical display time of screen partition C1 is t1, the historical display time of screen partition C2 is t2, and t1>t2, then the weight coefficient a of screen partition C1 is greater than the weight coefficient b of screen partition C2.

In some embodiments, a weight coefficient of each screen partition is determined based on the location information and historical display duration of the multiple screen partitions.

Taking Figure 26 as an example, the weight coefficient x is obtained according to the position information of the screen partition C1, and the weight coefficient y is obtained according to the position information of the screen partition C2. The weight coefficient a is obtained according to the historical display time t1 of the screen partition C1, and the weight coefficient b is obtained according to the historical display time t2 of the screen partition C1. Then, the weight coefficient of the screen partition C1 is ax, and the weight coefficient of the screen partition C2 is by.

The above embodiment determines the aging degree and usage frequency of the screen partitions according to the position information and/or historical display time of multiple screen partitions, thereby obtaining the weight coefficient required to determine the white balance parameters. It is then possible to focus on the screen partition with the highest possibility of burn-in to determine the white balance parameters, thereby more accurately adjusting the screen brightness.

After obtaining the weight coefficients of each screen partition, the target white balance parameters are determined according to the grayscale parameters of the target screen partition, so as to adjust the brightness according to the screen partition with the greatest degree of aging and/or the highest frequency of use, thereby protecting the screen to the greatest extent and preventing screen burn-in.

In some embodiments, the target white balance parameter is determined based on the weight coefficients of each screen partition and the grayscale parameters of the target screen partition. It can be understood that the white balance parameters of each screen partition are the same, that is, the screen achieves brightness adjustment of the entire screen based on one white balance parameter.

In some embodiments, the white balance parameters of each screen partition are determined separately according to the weight coefficients of each screen partition and the grayscale parameters of the target screen partition. It can be understood that the corresponding white balance parameters are determined for each screen partition, so that the brightness adjustment of the split screen can be achieved according to these white balance parameters to meet the diverse needs of users and enhance the user experience.

In addition, the target white balance parameters can be determined according to the white balance parameters of each screen partition to obtain the final target white balance parameters of the entire screen, so as to adjust the brightness of the entire screen and improve the uniformity of the brightness of the picture.

As mentioned above, the target grayscale range can be a grayscale range of two stages, so as to adjust the brightness of screen partitions with different grayscales in a targeted manner, thereby improving the accuracy of screen brightness adjustment. The following will describe the process of determining the target white balance parameters for the target screen partition corresponding to the first grayscale range and the target screen partition corresponding to the second grayscale range:

(1) The target screen partition is the screen partition whose grayscale parameters are continuously in the first grayscale range within the target duration.

If the target screen partition is a screen partition whose grayscale parameter is continuously in the first grayscale range within the target time length, the target white balance parameter is determined according to the first proportional coefficient. The first proportional coefficient is negatively correlated with the first grayscale range. It can be understood that the larger the grayscale parameter in the first grayscale range, the higher the brightness of the target screen partition, the greater the degree of adjustment required, and accordingly, the smaller the first proportional coefficient.

The first grayscale range is 60% to 80%, and the first proportional coefficient is set to 90%, which means that the white balance parameter of the screen is adjusted to 90% of the current white balance parameter.

(2) The target screen partition is the screen partition whose grayscale parameters are continuously in the second grayscale range within the target duration.

If the target screen partition is a screen partition whose grayscale parameter is continuously in the second grayscale range within the target time length, the target white balance parameter is determined according to the second proportional coefficient. The second proportional coefficient is negatively correlated with the second grayscale range. It can be understood that the larger the grayscale parameter in the second grayscale range, the higher the brightness of the target screen partition, the greater the degree of adjustment required, and accordingly, the smaller the second proportional coefficient.

The second grayscale range is greater than 80%, and the second proportional coefficient is set to 80%, which means that the white balance parameter of the screen is adjusted to 80% of the current white balance parameter.

In some embodiments, there are multiple target screen partitions. To better prevent screen burn-in, the target screen partition is the screen partition whose grayscale parameter is continuously in the second grayscale range within the target time length and whose grayscale parameter is the highest. Then, it is necessary to determine the white balance parameter for the target screen partition with the highest grayscale parameter and the most likely screen burn-in. The target white balance parameter is determined according to the second proportional coefficient and the grayscale parameter of the target screen partition.

In some embodiments, to ensure uniformity of screen brightness adjustment, the grayscale parameter is continuously in the target sub-grayscale range within the target duration, the target sub-grayscale range includes the first screen partition with the largest number, and then the target white balance parameter is determined according to the second proportional coefficient and the grayscale parameter of the target screen partition. The number ratio of the target screen partition in the multiple screen partitions can also be preset, for example, the screen partition whose grayscale parameter is continuously in the second grayscale range within the target duration and whose number ratio is greater than the preset number ratio is used as the target screen partition.

In some embodiments, considering the influence of ambient light, it is necessary to adjust the screen brightness in time when the ambient light changes, obtain the ambient light parameters, and then determine the target white balance parameters based on the ambient light parameters and the grayscale parameters corresponding to the target screen partition.

The ambient light parameters indicate that the current environment is brighter, and the screen has been in a high-brightness state for the target duration. If the brightness needs to be reduced, the ambient light parameters are obtained and combined with the grayscale parameters of the screen partitions to determine the target white balance parameters to adapt to the current environment. This ensures that the screen is visible in a brighter environment while reducing the screen brightness to prevent screen burn-in and save energy.

The above embodiment adjusts the screen brightness more accurately by partitioning the target screen into different grayscale ranges and adjusting according to different proportional coefficients.

Step 2404, adjusting the white balance parameters of the screen to the target white balance parameters.

In some embodiments, after obtaining the target white balance parameter, the brightness of the entire screen is adjusted. For example, the target white balance parameter is adjusted to 80% of the current white balance parameter, and the screen brightness is reduced to 80% of the current brightness.

In some embodiments, after obtaining the white balance parameters of each screen partition, the white balance parameters of each screen partition are adjusted to achieve brightness adjustment of the entire screen. As shown in Figure 30, Figure 30 is a schematic diagram of adjusting screen brightness provided by the present disclosure. In Figure 30, after determining that the white balance parameters of screen partitions S1, S3, S7, and S9 are 90%, the brightness of screen partitions S1, S3, S7, and S9 is adjusted to 90% of the current brightness, as shown in Figure 30 (a), and the current white balance parameter is 90%, which is adjusted to 81% as shown in Figure 30 (b). After determining that the white balance parameters of screen partitions S2, S4, S5, S6, and S8 are 80%, the current white balance parameter is 100% as shown in Figure 30 (a), and it is adjusted to 80% as shown in Figure 30 (b), achieving split screen brightness adjustment.

In addition, adjusting the screen brightness also includes increasing the screen brightness. The target grayscale range provided in the embodiment of the present application may be less than 60%. For example, the target grayscale range is 40% to 60%. Being at this brightness for a long time affects the user's viewing experience. Therefore, in an embodiment of the present application, an implementation method is provided to obtain the target white balance parameter before the target duration. When the white balance parameter is greater than the preset white balance parameter, the target white balance parameter is determined to be the target white balance parameter before the target duration, so as to restore the screen brightness and meet the diverse needs of users.

In some embodiments, similar to the above-mentioned improvement of screen brightness, white balance parameters of each screen partition may be determined according to the grayscale parameters of the target screen partition and the weight coefficients of each screen partition.

As shown in FIG31 , FIG31 is a schematic diagram of adjusting screen brightness provided by the present disclosure. In FIG31 , after determining that the white balance parameters of screen partitions S1, S3, S7, and S9 are 40%, it is determined that the white balance parameters of screen partitions S1, S3, S7, and S9 are 60% before the target duration, and the white balance parameters of screen partitions S1, S3, S7, and S9 are adjusted to 60%, as shown in FIG31 (a), and the current white balance parameter is 40% and adjusted to 60% as shown in FIG31 (b). After determining that the white balance parameters of screen partitions S2, S4, S5, S6, and S8 are 50%, it is determined that the white balance parameters of screen partitions S2, S4, S5, S6, and S8 are 60% before the target duration, and the current white balance parameter is 50% as shown in FIG31 (a), and is adjusted to 60% as shown in FIG31 (b), realizing the split screen restoration brightness.

In summary, the present disclosure provides a display control method, which is used for screen brightness adjustment. The method divides the screen of a display device into multiple screen partitions, obtains the grayscale parameters of each screen partition within a target duration, and then determines the target screen partition from the multiple screen partitions according to the grayscale parameters of each screen partition. The target screen partition is a screen partition whose grayscale parameters are within a target grayscale range within a target duration; further, the target white balance parameters are determined according to the grayscale parameters corresponding to the target screen partition, and finally the screen brightness is adjusted according to the white balance parameters. The brightness adjustment is achieved by partitioning the screen, which improves the efficiency of screen brightness adjustment, and the brightness of the screen is monitored within the target duration to adjust the brightness in a timely manner, thereby preventing the display device from burning in and improving the display effect of the picture.

Claims (28)

1. A projection device, comprising:

   a light machine configured to project the play content to a projection surface;

   A lens including an optical assembly and a driving motor; the driving motor is connected with the optical component to adjust the focal length of the optical component;

   A distance sensor configured to detect a separation distance between the projection surface and the optical machine;

   A camera configured to capture a projected content image;

   A controller configured to:

   responding to an automatic focusing instruction, and acquiring the interval distance;

   If the interval distance is smaller than an interval judgment threshold value, calculating a first focusing amount according to the interval distance, and controlling the driving motor to adjust the focal length of the optical component according to the first focusing amount;

   And if the interval distance is larger than or equal to an interval judgment threshold value, calculating a second focusing amount according to the definition of the projection content image, and controlling the driving motor to adjust the focal length of the optical component according to the second focusing amount.
2. The projection device of claim 1, the controller configured to:

   acquiring distance detection frame data generated by the distance sensor in a multi-scanning process;

   traversing the number of target objects in a plurality of the distance detection frame data;

   if the number of the target objects is smaller than or equal to a number judgment threshold, calculating the interval distance according to the target distance between each target object and the optical machine;

   And if the number of the target objects is larger than a number judgment threshold, calculating a second focusing amount according to the definition of the projection content image.
3. The projection device of claim 2, the controller configured to:

   Traversing a target distance between each target object in the distance detection frame data and the optical machine;

   Setting the distance confidence of the target object according to the target distance, including: if the target distance is within a preset effective interval, setting the distance reliability as a first numerical value; if the target distance is not in the preset effective interval, setting the distance reliability as a second numerical value; the first value is greater than the second value;

   and calculating the average value of the target distances corresponding to the target objects, of which the distance confidence is the first value, so as to generate the interval distance.
4. The projection device of claim 1, the controller configured to:

   A first moving instruction is sent to the driving motor so as to control the driving motor to move the optical component from a focusing start position to a focusing end position;

   In the moving process of the optical component, acquiring projection content images shot by the camera according to preset frequency, wherein each projection content image is associated with a focusing position;

   Calculating the definition of the projection content image;

   and searching the optimal focusing position according to the definition of the projection content image.
5. The projection device of claim 4, the controller configured to:

   ordering the focusing positions according to the definition of the projection content image to obtain a definition sequence;

   Extracting a fine focusing interval from the definition sequence, wherein the corresponding focusing position of the projection content image with the highest definition is in the fine focusing interval;

   sending a second movement instruction to the driving motor to control the optical component to move in the fine focusing interval according to a preset adjustment step length;

   acquiring a fine focusing image shot by the camera after each movement of the optical component;

   Calculating the definition of the fine focusing image, and searching an optimal focusing position according to the definition of the fine focusing image, wherein the optimal focusing position is the focusing position corresponding to the fine focusing image with the highest definition.
6. The projection device of claim 4, the controller configured to:

   acquiring a moving speed of the driving motor and acquiring a shooting frequency of the camera;

   calculating a position compensation value according to the moving speed and the shooting frequency;

   extracting a focusing position corresponding to the projection content image with highest definition to obtain a target focusing position;

   And correcting the target focusing position by using the position compensation value to obtain the optimal focusing position.
7. The projection device of claim 1, further comprising a pose sensor configured to detect pose information of the projection device; the controller is configured to:

   Extracting boundary coordinates of a key area, wherein the boundary coordinates are vertex coordinates stored according to the corrected key area when the projection equipment executes trapezoidal correction;

   If the storage time of the boundary coordinates is in the available period, cutting the projection content image by using the boundary coordinates;

   And if the storage time of the boundary coordinates is not in the available period, acquiring the gesture information through the gesture sensor, and cutting the projection content image according to the gesture information.
8. The projection device of claim 7, the controller configured to:

   comparing the current posture information with original posture information stored in the trapezoid correction process;

   If the difference value between the current gesture information and the original gesture information is larger than a gesture detection threshold value, detecting a highlight region in the projection content image, and cutting the projection content image according to the shape of the highlight region;

   And if the difference value between the current gesture information and the original gesture information is smaller than or equal to a gesture detection threshold value, cutting the projection content image by using the boundary coordinates.
9. The projection device of claim 1, the controller configured to:

   Detecting the interval variation in real time through the distance sensor;

   if the interval variation exceeds the variation threshold, acquiring a projection content image;

   Identifying an interference target in the projected content image;

   And when the interference target is contained in the projection content image, sending a pause instruction to the driving motor so as to pause the adjustment of the focal length of the optical component.
10. The projection device of claim 1, the controller further configured to: identifying a projection area of the projection device by using an edge detection algorithm based on the projection content image acquired by the camera; when the projection area is displayed as a rectangle or a rectangle-like shape, the controller acquires coordinate values of four vertexes of the rectangular projection area through a preset algorithm.
11. The projection device of claim 10, the controller further configured to: and correcting the projection area into a rectangle by using a perspective transformation method, and calculating the difference between the rectangle and the projection screen shot to judge whether foreign matters exist in the display area.
12. The projection device of claim 10, the controller further configured to: when foreign matter detection is realized on a certain area outside the projection area, the camera content of the current frame and the camera content of the previous frame can be made into a difference value to judge whether foreign matter enters the area outside the projection area; if the foreign matter is judged to enter, the function of preventing the injection of eyes is automatically triggered.
13. The projection device of claim 10, the controller further configured to: detecting real-time depth changes of the specific area with a time-of-flight camera, or a time-of-flight sensor; and if the change of the depth value exceeds a preset threshold value, automatically triggering the eye-shot prevention function.
14. The projection device of claim 10, the controller further configured to: and analyzing and judging whether an eye-shooting prevention function needs to be started or not based on the collected flight time data, screenshot data and camera data.
15. The projection device of claim 10, the controller further configured to: if the specific object is detected to be located in the preset area, the eye-shot prevention function is automatically started, so that the laser intensity emitted by the optical machine is reduced, the display brightness of the user interface is reduced, and the safety prompt information is displayed.
16. The projection device of claim 10, the controller further configured to: monitoring the movement of the device by a gyroscope, or a gyroscopic sensor; signaling for inquiring the state of the equipment is sent to the gyroscope, and signaling for judging whether the equipment moves or not is received from the gyroscope.
17. The projection device of claim 10, the controller further configured to:

    after the gyroscope data is stable for a preset time length, controlling the starting to trigger the trapezoidal correction, and not responding to an instruction sent by a key of the remote controller when the trapezoidal correction is performed.
18. The projection device of claim 10, the controller further configured to:

    The curtain is identified through an automatic obstacle avoidance algorithm, projection changes are utilized, projection content images are corrected to the inside of the curtain to be displayed, and the effect of alignment with the edge of the curtain is achieved.
19. The projection device of claim 1, the controller further configured to:

    Determining a plurality of screen partitions, and acquiring gray scale parameters of each screen partition in a target duration;

    Determining a target screen partition from the plurality of screen partitions according to the gray scale parameters of each screen partition, wherein the target screen partition is a screen partition with the gray scale parameters in a target gray scale range in the target duration;

    determining a target white balance parameter according to the gray scale parameter of the target screen partition;

    and adjusting the white balance parameter of the screen to the target white balance parameter.
20. The projection device of claim 19, the controller configured to: determining a weight coefficient of each screen partition in the plurality of screen partitions according to the position information of the plurality of screen partitions and/or a history display time length, wherein the history display time length is the history time length of each screen partition in the target gray scale range;

    And determining the target white balance parameter according to the gray scale parameter of the target screen partition and the weight coefficient of each screen partition.
21. The projection device of claim 20, the controller further configured to: and respectively determining the white balance parameters of each screen partition according to the gray scale parameters of the target screen partition and the weight coefficients of each screen partition.
22. The projection device of claim 19, the target duration and the target gray scale range being determined according to a type of content to be displayed of the plurality of screen partitions.
23. The projection device of claim 19, the controller further configured to: acquiring an ambient light parameter;

    The controller is configured to: and determining the target white balance parameter according to the gray scale parameter of the target screen partition and the ambient light parameter.
24. The projection apparatus of claim 19, wherein the target gray scale range is a first gray scale range that is a range greater than a first preset gray scale threshold and less than a second preset gray scale threshold;

    The controller is configured to:

    And determining the target white balance parameter according to a first scale coefficient and the gray scale parameter of the target screen partition, wherein the first scale coefficient corresponds to the first gray scale range.
25. The projection apparatus of claim 19, wherein the target gray scale range is a second gray scale range, the second gray scale range being a range greater than or equal to a second preset gray scale threshold;

    The controller is configured to:

    and determining the target white balance parameter according to a second proportionality coefficient and the gray scale parameter of the target screen partition, wherein the second proportionality coefficient corresponds to the second gray scale range.
26. The projection device of claim 19, wherein the gray scale parameter of the target screen section is a highest gray scale parameter in the respective screen section.
27. The projection device of claim 25, the target gray scale range being a second gray scale range, the second gray scale range comprising at least two sub-gray scale ranges, the target screen partition comprising m screen partitions, the m screen partitions being at least two screen partitions of the plurality of screen partitions;

    The controller is configured to:

    Determining a first screen partition from the m screen partitions, wherein the first screen partition is a screen partition in a target sub-gray scale range in the m screen partitions;

    The number of the screen partitions of the gray scale parameters in the target sub-gray scale range is larger than the number of the screen partitions in other sub-gray scale ranges, and the other sub-gray scale ranges are sub-gray scale ranges except the target sub-gray scale ranges in the at least two sub-gray scale ranges;

    and determining the target white balance parameter according to the second proportionality coefficient and the gray scale parameter of the first screen partition.
28. A display control method for a projection device, the projection device comprising an optical machine, a lens, a distance sensor, a camera, and a controller; the lens comprises an optical component and a driving motor, wherein the driving motor is connected with the optical component so as to adjust the focal length of the optical component; the display control method includes:

    Acquiring a spacing distance through the distance sensor in response to an automatic focusing instruction;

    If the interval distance is smaller than an interval judgment threshold value, calculating a first focusing amount according to the interval distance, and controlling the driving motor to adjust the focal length of the optical component according to the first focusing amount;

    And if the interval distance is larger than or equal to an interval judgment threshold value, calculating a second focusing amount according to the definition of the projection content image, and controlling the driving motor to adjust the focal length of the optical component according to the second focusing amount.