KR102212110B1 - Method and apparatus for compensating handwriting data in electronic pen - Google Patents

Abstract

The laser light is irradiated toward the surface, the speckle pattern based on the irradiated laser light is detected and converted into an image signal, the moving direction and the moving distance of the pen tip are detected by comparing the speckle pattern of the image signal, and the detected electrons A method of correcting writing data for correcting the movement direction and movement distance of the detected pen tip using the inclination direction and angle of the pen, and transmitting the corrected movement direction and movement distance of the pen tip to the outside when a pressure detection signal is received, and The device is disclosed.

Description

Method and apparatus for compensating handwriting data in electronic pen TECHNICAL FIELD

The present invention relates to a method and an apparatus for correcting handwritten data in an electronic pen, and more particularly, based on a speckle pattern image obtained after irradiating a laser light onto a surface without a predetermined code, the electronic pen pen tip The present invention relates to a method and apparatus for correcting handwritten data for obtaining a moving distance of and correcting it according to a tilt direction and angle of an electronic pen.

Existing pen mouse products are generally only pen-shaped mice. Thus, users have felt awkward and uncomfortable when using a product with a product in their hand or when drawing something on a computer.

Moreover, most of them are made much larger than ordinary pens by using mouse sensors and lenses, and due to low DOF characteristics, handwriting errors depending on the holding direction and angle of the pen, they actually only have the characteristics of a mouse rather than a pen.

In addition, recently, when the electronic pen writes on a paper on which a predetermined code is printed, the code is acquired according to the handwriting trajectory using a camera attached to the electronic pen, and based on this, the writing trajectory is digitally generated in the application of the smartphone. The technology to mark as an enemy has been developed and used. However, since a medium on which a predetermined code is printed is required, there has been a limitation in that the handwriting cannot be digitally displayed on paper or the like on which the code is not printed.

In addition, even if the handwriting data is acquired, there has been a problem in that the handwriting cannot be accurately restored due to distortion due to the tilt of the pen.

In order to solve this problem, the present invention provides a writing data correction method and apparatus for accurately correcting the acquired handwriting data by sensing the tilt direction and angle of an electronic pen after acquiring handwritten data.

According to an embodiment of the present invention for solving the above technical problem, a method for correcting handwriting data includes: irradiating a laser light toward a surface; Detecting a speckle pattern based on the irradiated laser light and converting it into an image signal; Comparing the speckle pattern of the image signal to detect a moving direction and a moving distance of the pen tip; Correcting a movement direction and a movement distance of the detected pen tip by using the detected inclination direction and angle of the electronic pen; And transmitting the corrected movement direction and movement distance of the pen tip to the outside when receiving the pen pressure detection signal.

The step of correcting the movement direction and the movement distance of the detected pen tip using the detected inclination direction and angle of the electronic pen includes: a scale factor according to the detected inclination direction and angle of the electronic pen is adjusted to move the detected pen tip. It may include the step of multiplying the direction and the moving distance to correct.

The scale factor may be determined by a change in the number of counts per unit movement distance of the image sensing unit according to the sensed inclination direction and angle of the electronic pen.

According to an embodiment of the present invention for solving the above technical problem, a writing data correction device includes a light emitting unit that irradiates a laser light toward a surface; An image sensing unit detecting a speckle pattern based on the irradiated laser light and converting it into an image signal; An inertial measurement unit that detects the inclination direction and angle of the electronic pen; And comparing the speckle pattern of the image signal to detect the movement direction and the movement distance of the pen tip, and using the inclination direction and angle of the electronic pen detected by the inertial measurement unit, the detected movement direction of the pen tip and And an image data processing unit that corrects the movement distance and transmits the corrected movement direction and movement distance of the pen tip to the outside when receiving a pen pressure detection signal.

According to the present invention, since handwriting data is corrected according to the direction and angle of the electronic pen, accurate handwriting data can be electronically restored even when the pen is held in any direction and at any angle.

1 is a schematic diagram of an electronic pen according to an embodiment of the present invention.
2 is a diagram illustrating a partial cross-sectional view of an electronic pen according to an embodiment of the present invention.
3 is a block diagram of a location sensing module according to an embodiment of the present invention.
4 is a diagram illustrating a cross-sectional view of a position sensing module according to an embodiment of the present invention.
5 is a flowchart illustrating a method of correcting handwriting data of an electronic pen according to an embodiment of the present invention.
6 is a block diagram illustrating a device for correcting handwriting data of an electronic pen according to an embodiment of the present invention.

A preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

According to the present invention, the electronic pen 100 is a pen that electronically restores writing by detecting movement of a laser speckle pattern on a surface or paper without a printed code.

1 is a diagram illustrating a schematic diagram of an electronic pen according to an embodiment of the present invention, and FIG. 2 is a view showing a cross-sectional view of a part of the electronic pen (a dotted line in FIG. 1) according to an embodiment of the present invention. 3 is a block diagram of a location sensing module according to an embodiment of the present invention, and FIG. 4 is a cross-sectional view of a location sensing module according to an embodiment of the present invention.

1 to 4, the electronic pen 100 includes a housing 110, a pen tip 120, a pressure sensing unit 130, and a position sensing module 140, and the position sensing module 140 emits light. A unit 141, an image sensing unit 142, an inertial measurement unit 143, a control unit 144 and an IR pass filter 145 are included, which are arranged in the barrel 146. Although not shown in the drawings, the electronic pen 100 may further include a control unit, a battery, a memory, a transmission unit, and/or an input/output interface for overall controlling the functions of the electronic pen 100.

The housing 110 corresponds to the main body of the electronic pen, is elongated in one direction, and has a first opening and a second opening at a lower end thereof.

The first opening is a hollow formed to expose the pen tip 120, and the second opening is a hollow formed to receive light irradiated from the position sensing module 140 and light reflected from the surface.

The pen tip 120 is a unit for writing by ejecting ink on a surface (eg, paper, etc.), and is coupled to the housing 110 to be exposed to the outside through a first opening of the housing 110.

When the pen tip 120 writes on the surface, the pen pressure sensing unit 130 senses the pressure by the pen tip 120 because the pen tip 120 moves opposite the surface. When the pen pressure sensing unit 130 detects the pressure, it transmits a writing start signal to the position sensing module 140.

When the electronic pen 100 is powered on and the pen pressure sensing unit 130 cannot sense the pressure, the hover mode is maintained.

The barrel 146 accommodates the light emitting unit 141, the image sensing unit 142, the inertial measurement unit 143, the control unit 144 and the IR pass filter 145 of the position sensing module 140 therein, It is formed in a hollow shape and is disposed above the second opening 112 in the housing 110.

The barrel 146 is a device for removing interference signals caused by ambient light as much as possible. Since the image sensing unit 142 is highly affected by the interference signal, the barrel 146 is a unit for removing the inflow of ambient light as much as possible.

In addition, in order to remove the interference signal as much as possible, the distance (d) from the center of the image sensing unit 120 to the center of the lower end of the barrel 146 is 4.0 to 8.0 millimeters (mm), and the barrel 146 The diameter of can be limited to a size of 6.2 millimeters (mm) or more.

In addition, in order to minimize the inflow of interference light signals other than the light scattered from the surface to the sensor, the interior of the barrel is matted. In addition, for this purpose, a dark-based material is simultaneously applied to the interior of the barrel, so that the interior surface of the barrel can be treated.

Further, the lower end of the barrel 146 is formed to be inclined at a second angle (b) to correspond to the arrangement of the IR pass filter 145, and the IR pass filter 145 is a reference length (h) from the lower end of the barrel 146 It is installed in the inserted state. The reference length h may be 0.8 millimeters to 1.2 millimeters. In addition, the interference light reflected from the inner surface of the barrel 146 from the IR pass filter 145 to the lower end of the barrel 146 is condensed toward the image sensing unit 142, that is, the inflow of light scattered from the surface is maximized. , The inner surface of the barrel 146 from the IR pass filter 145 to the lower end of the barrel 146 may be treated with nanoparticles. For even greater effect, the inner surface of the barrel 146 from the IR pass filter 145 to the lower end of the barrel 146 may be formed in a serrated shape or an uneven shape.

The light emitting unit 141 irradiates light when the electronic pen 100 is turned on. In another embodiment of the present invention, when receiving a writing start signal, the light emitting unit 141 may irradiate light toward the surface. The light emitting unit 141 is installed on the top of the barrel 146. In one embodiment of the present invention, the light emitting unit 140 is preferably a laser. This is because a speckle pattern can be generated using a wavefront interference phenomenon of a plurality of lights scattered from a surface only when a laser is used.

The light emitting unit 141 has a first angle upward with respect to a direction orthogonal to the length direction of the housing 110 so that the laser light irradiated from the light emitting unit 141 is irradiated in the longitudinal direction and inclined direction of the housing 110. It is placed obliquely. When the laser light is irradiated in the same direction as the length direction of the housing 110, interference is caused by the pen tip 120. Therefore, the laser light should be irradiated obliquely to the right in the direction of the pen tip 120. In addition, when the laser light is irradiated too obliquely, since the exact position of the pen tip 120 cannot be restored, there is no influence of the pen tip 120, and in order to restore the writing according to the relatively accurate position of the pen tip 120 , The first angle is preferably 10° to 12°.

The laser light is irradiated to the surface, and a speckle pattern is formed due to coherent reflected from the surface, and the image sensing unit 142 detects the speckle pattern It converts to a video signal. After that, the image sensing unit 142 transmits the converted image signal to the control unit 143. In the present invention, the image sensing unit 142 may be a CCD or CMOS. The light emitting unit 141 and the image sensing unit 142 may be integrally formed and provided as a single module.

The inertial measurement unit 143 is composed of an acceleration sensor and a gyro sensor, and acquires information on the direction and angle of the electronic pen 100.

The control unit 144 compares the speckle pattern image received from the image sensing unit 142 to detect the moving direction and the moving distance of the pen tip. The control unit 144 sets a speckle pattern image subset of the position (current position) after the position change of the pen tip 120, and the image of the currently set subset and the position before the position change (previous position) The previous position is searched for the highest correlation of the pen tip 120, and the position change and velocity from the previous position to the current position of the pen tip 120 are detected.

In addition, the control unit 144 may correct the movement direction and movement distance of the pen tip by using the direction and angle of the pen sensed by the inertia measurement unit 143.

The control unit 144 receives a pen pressure detection signal from the pen pressure sensing unit 130. Thereafter, the control unit 144 may generate a writing start signal, and may transmit it to the light emitting unit 141.

When the control unit 144 receives the pen pressure detection signal, it transmits data on the movement direction and movement distance of the pen tip 120 after reception to an external device (not shown). Thereafter, the external device digitally restores and displays the offline handwriting of the electronic pen 100 according to the received data. When the control unit 144 does not receive the pen pressure detection signal, the hover mode is maintained.

The IR pass filter 145 is disposed to transmit light only in a specific IR frequency band, and is provided to improve a signal-to-interference ratio (SNR). The central wavelength of the IR pass filter 145 must be matched to the wavelength of the laser light.

The IR pass filter 145 is also disposed to be inclined at a second angle upward with respect to the direction orthogonal to the longitudinal direction of the housing 110 like the light emitting unit 141. Here, when the first angle and the second angle are the same, there is a problem that the light directly reflected by the IR pass filter 145 causes an interference signal, so the first angle and the second angle must be different. . The second angle is greater than the first angle (a), and is preferably 33° to 39°.

5 is a flowchart illustrating a method of correcting handwriting data of an electronic pen according to an embodiment of the present invention.

Referring to FIG. 5, in step 510, the electronic pen irradiates a laser light toward the surface. The laser light is irradiated through a light emitting element provided in the electronic pen.

The electronic pen irradiates light when the power is turned on. In another embodiment of the present invention, when receiving a writing start signal, the electronic pen may irradiate light toward the surface. In the present invention, the light is preferably laser light. This is because a speckle pattern can be generated using a wavefront interference phenomenon of a plurality of lights scattered from a surface only when a laser is used.

In step 520, the electronic pen detects a speckle pattern caused by wavefront interference of a plurality of lights scattered from the surface and converts it into an image signal. The image sensing unit provided in the electronic pen performs this step. As the image sensing unit, a CCD or CMOS may be used.

In step 530, the electronic pen compares the received speckle pattern image to detect a movement direction and a movement distance of the pen tip. The electronic pen sets the speckle pattern image subset of the position (current position) after the position change of the pen tip, and does the image of the currently set subset have the highest correlation with the position before the position change (previous position)? It scans to find the previous position, and detects the position change and velocity from the previous position of the pen tip to the current position.

In step 540, the electronic pen may correct a movement direction and a movement distance of the detected pen tip by using the inclination direction and angle of the pen detected through the inertial measurement unit. The inertial measurement unit is composed of an acceleration sensor and a gyro sensor, and acquires information on the tilt direction and angle of the electronic pen, specifically, the image sensing unit.

The electronic pen corrects by multiplying the movement direction and movement distance of the pen tip detected according to the inclination direction and angle of the pen detected by the inertial measurement unit by a scale factor. In one embodiment of the present invention, the scale factor is different according to the angle of the electronic pen, and even if the angle is the same, the scale factor is in the case where the inclination direction of the electronic pen is in the X-direction and in the Y-direction. Different.

The scale factor is determined by a change in the number of counts per unit movement distance of the image sensing unit according to the tilt direction and angle of the electronic pen. When the angle of the electronic pen is tilted than the number of counters per unit movement distance of the image sensing unit when the direction of the electronic pen is perpendicular to the surface, the number of counts per unit movement distance of the image sensing unit is smaller. Therefore, when the angle of the electronic pen is not perpendicular to the surface, correction is performed by multiplying by one or more scale factors.

Table 1 below is a table showing an experimental example of the scale factor according to the X-direction and angle of the electronic pen.

X-direction angle Scale factor >40 1.43 36 to 40 1.33 31 to 35 1.25 26 to 30 1.18 21-25 1.11 16 to 20 1.05 0 to 15 1.00

Table 2 below is a table showing an experimental example of the scale factor according to the Y-direction and angle of the electronic pen.

Y-direction angle Scale factor >45 1.33 41 to 45 1.25 36 to 40 1.18 31 to 35 1.11 26 to 30 1.05 -5 to 25 1.00 -10 ~ -6 1.05 -15 ~ -11 1.11 -20 ~ -16 1.18 -25 ~ -21 1.25 -30 ~ -26 1.33 <-30 1.43

In Tables 1 and 2, the angle refers to an angle that differs when the direction of the electronic pen is perpendicular to the surface.

In step 550, when receiving the pen pressure detection signal, the electronic pen transmits data on the corrected movement direction and movement distance of the pen tip to the outside.

Thereafter, the device connected to the electronic pen digitally restores the handwriting of the electronic pen based on the received movement direction and movement distance of the pen tip.

6 is a block diagram illustrating a device for correcting handwriting data of an electronic pen according to an embodiment of the present invention.

Referring to FIG. 6, the handwriting data correction device 600 includes a light emitting unit 610, an image sensing unit 620, an inertial measurement unit 630, an image data processing unit 640, and further includes an IR pass filter. It can also be included. The components of FIG. 6 perform the same functions as the components of FIG. 3, and the image data processing unit 640 performs the same functions as the control unit 144 of FIG. 3.

The light emitting unit 610 irradiates a laser light toward the surface.

When the electronic pen is powered on, the light emitting unit 610 irradiates light. In another embodiment of the present invention, when receiving a writing start signal, the light emitting unit 610 may irradiate light toward the surface. In the present invention, the light is preferably laser light. This is because a speckle pattern can be generated using a wavefront interference phenomenon of a plurality of lights scattered from a surface only when a laser is used.

The image sensing unit 620 detects a speckle pattern due to wavefront interference of a plurality of lights scattered from a surface and converts it into an image signal. The image sensing unit 620 may be a CCD or CMOS.

The image data processing unit 640 detects a moving direction and a moving distance of the pen tip by comparing the received speckle pattern image. The image data processing unit 640 sets a subset of the speckle pattern image of the position (current position) after the position change of the pen tip 120, and has the most correlation between the image of the currently set subset and the position (previous position) before the position change. It scans whether or not is high to find the previous position, and detects the position change and velocity from the previous position of the pen tip to the current position.

The image data processing unit 640 may correct a movement direction and a movement distance of the detected pen tip by using the inclination direction and angle of the pen sensed through the inertial measurement unit 630. The inertia measurement unit 630 is composed of an acceleration sensor and a gyro sensor, and acquires information on the tilt direction and angle of the electronic pen, specifically, the image sensing unit 620.

The image data processing unit 640 multiplies the movement direction and movement distance of the detected pen tip by a scale factor according to the inclination direction and angle of the pen detected by the inertial measurement unit to correct. In one embodiment of the present invention, the scale factor is different according to the angle of the electronic pen, and even if the angle is the same, the scale factor is in the case where the inclination direction of the electronic pen is in the X-direction and in the Y-direction. Different.

The scale factor is determined by a change in the number of counts per unit movement distance of the image sensing unit 620 according to the tilt direction and angle of the electronic pen. When the angle of the electronic pen is inclined than the number of counters per unit movement distance of the image sensing unit 620 when the direction of the electronic pen is perpendicular to the surface, the number of counts per unit movement distance of the image sensing unit 620 decreases. Therefore, when the angle of the electronic pen is not perpendicular to the surface, correction is performed by multiplying by one or more scale factors.

When receiving the pen pressure detection signal, the image data processing unit 640 transmits data on the corrected movement direction and movement distance of the pen tip to the outside.

Thereafter, the device connected to the electronic pen digitally restores the handwriting of the electronic pen based on the received movement direction and movement distance of the pen tip.

The handwriting data correction method as described above can also be implemented as a computer-readable code on a computer-readable recording medium. The computer-readable recording medium includes all types of recording media storing data that can be read by a computer system. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, and optical data storage devices. In addition, the computer-readable recording medium is distributed over a computer system connected through a network, so that computer-readable codes can be stored and executed in a distributed manner. Further, functional programs, codes, and code segments for implementing the disk management method can be easily inferred by programmers in the technical field to which the present invention belongs.

So far, the present invention has been looked at around its preferred embodiments. Those of ordinary skill in the art to which the present invention pertains will be able to understand that the present invention may be implemented in a modified form without departing from the essential characteristics of the present invention. Therefore, the disclosed embodiments should be considered from an illustrative point of view rather than a limiting point of view. The scope of the present invention is shown in the claims rather than the above description, and all differences within the scope equivalent thereto should be construed as being included in the present invention.

Handwriting data correction device...600
Light-emitting unit...610 Image sensing unit...620
Inertial Measurement Unit...630 Image Data Processing Unit...640

Claims (6)

Irradiating a laser light toward the surface;
Detecting a speckle pattern based on the irradiated laser light and converting it into an image signal;
Comparing the speckle pattern of the image signal to detect a moving direction and a moving distance of the pen tip;
Correcting a movement direction and a movement distance of the detected pen tip by using the inclination direction and angle of the electronic pen sensed through an inertial measurement unit provided in the electronic pen; And
When receiving the pen pressure detection signal, including the step of transmitting the movement direction and movement distance of the corrected pen tip to the outside,
Using the sensed inclination direction and angle of the electronic pen, the step of correcting the detected movement direction and movement distance of the pen tip,
Compensating by multiplying a scale factor according to the detected tilt direction and angle of the electronic pen by the detected movement direction and movement distance of the pen tip,
And the scale factor is determined by a change in the number of counts per unit movement distance of the image sensing unit according to the sensed tilt direction and angle of the electronic pen. delete delete A light-emitting unit that irradiates a laser light toward the surface;
An image sensing unit detecting a speckle pattern based on the irradiated laser light and converting it into an image signal;
An inertial measurement unit that detects an inclination direction and an angle of the electronic pen; And
By comparing the speckle pattern of the image signal, the moving direction and the moving distance of the pen tip are detected, and using the inclination direction and angle of the electronic pen sensed by the inertial measurement unit, the movement direction and movement of the detected pen tip Compensating the distance, and when receiving a pen pressure detection signal, including an image data processing unit for transmitting the movement direction and the movement distance of the corrected pen tip to the outside,
The image data processing unit corrects by multiplying a scale factor according to the sensed inclination direction and angle of the electronic pen by the detected movement direction and movement distance of the pen tip,
And the scale factor is determined by a change in the number of counts per unit movement distance of the image sensing unit according to the sensed tilt direction and angle of the electronic pen. delete delete

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