JP2010041399A - Imaging device and its control method - Google Patents

Abstract

An object of the present invention is to provide an imaging apparatus capable of suppressing the start of shooting due to detection of an unintended target when shooting is performed while detecting a target.
When face information is detected by a face detection unit 101 (T1), in the first face number determination process A before SW1 is turned on, the number of face information detected once is used. The number of faces is determined (T2). On the other hand, in the face number determination process B executed after SW2 is turned on, chattering is started at the timing (T3) when the face is detected by the face detection unit 101, and the detection result is a predetermined number of times (5 times). Is referenced. When the number of faces is held, the face is included in the number of faces for the first time (T4). That is, only the faces detected five times consecutively by the face detection unit 101 are counted as the number of faces. Therefore, even if an unintended passing person enters the screen, the photographing process in the face self-timer mode is not started.
[Selection] Figure 6

Description

  The present invention relates to an imaging apparatus that detects and captures a target and a control method thereof.

In recent years, digital cameras equipped with a face detection function for detecting a human face from images displayed on a liquid crystal screen of a digital camera have appeared. An imaging function that uses this function as a trigger for increasing the number of faces has been proposed. By using this technique, self-timer shooting that could not be started until a predetermined time has elapsed can be shot at the timing when the shooting instructor who gives the release start instruction enters the angle of view. . For example, Patent Document 1 discloses a camera that performs photographing after a predetermined time since a face is newly detected.
JP 2006-301172 A

  However, in a mode in which shooting processing is started in response to the detection of a new face (hereinafter referred to as “face self-timer mode”), the following operations are performed, and there are the following problems. When the shutter button is pressed halfway and the shutter switch SW1 is turned on, the number of in-focus faces and other recognized faces are counted. Then, after the shutter button was fully pressed and the shutter switch SW2 was turned on, the image was taken when the number of faces increased from this count.

  When face detection is performed with the same face detection accuracy as before the shutter switch SW2 is turned on, the face of an unintended intruder (for example, a passing person) is detected, and the intruder is included. However, there was a risk that shooting was started by an unintended shot member. Moreover, there is a possibility that the background shadow or the like is erroneously detected as a face, and shooting is started at a timing unintended by the photographer.

  On the other hand, if the conditions for detecting a face as a whole are strictly set, the success frequency of face detection will decrease, and it will not be possible to smoothly follow the position of the face, for example, when the subject moves. End up.

  Therefore, the present invention provides an imaging apparatus and a control method thereof that can suppress the start of shooting due to detection of an unintended target when shooting is performed while detecting a target. With the goal.

  In order to achieve the above object, an image pickup apparatus according to the present invention is an image pickup apparatus for picking up an image. The detection means detects a target satisfying a predetermined condition from the picked-up image, and the detection means detects the target. Storage means for storing the number of the target objects as a reference value; and after the reference value is stored by the storage means, if the number of the target objects detected by the detection means is different from the reference value, a predetermined operation is performed. Operating means for starting, wherein the detecting means sets the condition after the reference value is stored strictly compared with the condition before the reference value is stored.

  According to another aspect of the present invention, there is provided a control method for an image pickup apparatus, wherein the detection unit of the image pickup apparatus detects a target satisfying a predetermined condition from the picked-up image. A storage step in which the storage unit of the imaging device stores the number of the targets detected in the detection step as a reference value; and an operation unit of the imaging device stores the reference value in the storage step; An operation step of starting a predetermined operation when the number of targets detected in the detection step is different from the reference value according to the condition set stricter than the condition before the reference value is stored; It is characterized by having.

  In the imaging apparatus according to claim 1 of the present invention, after the reference value is stored, the number of detected targets is determined as the reference value according to a condition set strictly compared with a condition before the reference value is stored. If they are different, a predetermined operation is started. In this way, by setting the conditions after the reference value is memorized strictly, shooting is performed by detecting an unintended target (such as the face of a passing person) when shooting while detecting the target. Can be prevented from starting.

  In addition, prior to storing the reference value, priority can be given to the responsiveness of target detection so that even if the target moves, tracking can be performed immediately.

  According to the imaging device of the second aspect, it is possible to prevent erroneous detection of a target due to an unintended target (such as an intruder's face) or background shadow, and to reduce the start of a predetermined operation due to erroneous detection. Can do.

  According to the image pickup apparatus of the third aspect, it is possible to detect the target with a relatively small movement or a similar size and direction, and prevent erroneous detection of the target.

  According to the imaging device of the fourth aspect, the accuracy of the target detection process after the second switch is pressed is improved, and erroneous detection due to the face of a person passing by as a target, the shadow of the shooting background, or the like is prevented. And release without failure.

  According to the imaging device of the fifth aspect, depending on the set shooting mode, only the in-focus state can be displayed when only the in-focus state is necessary. It is also possible to display so that all faces can be recognized. As a result, the currently detected face can be easily recognized, and it can also be recognized that it is listed as a candidate to which the process is applied when performing a process related to the face.

  Embodiments of an imaging apparatus and a control method thereof according to the present invention will be described with reference to the drawings. The imaging apparatus of this embodiment is applied to a digital camera.

  FIG. 1 is a block diagram illustrating a configuration of a digital camera according to an embodiment. The digital camera 100 includes a photographing lens 10, a shutter 12 having a diaphragm function, an image sensor 14 that converts an optical image into an electric signal, and an A / D converter that converts an analog signal output from the image sensor 14 into a digital signal. 16 is provided.

  The timing generation circuit 18 supplies a clock signal and a control signal to the image sensor 14, the A / D converter 16 and the D / A converter 26, and is controlled by the memory control circuit 22 and the system control circuit 50. The

  The image processing circuit 20 performs predetermined pixel interpolation processing and color conversion processing on the data from the A / D converter 16 or the data from the memory control circuit 22. Further, the image processing circuit 20 performs a predetermined calculation process using the captured image data. The image processing circuit 20 includes a TTL (through-the-lens) AF (autofocus) process when the system control circuit 50 controls the exposure control unit 40 and the distance measurement control unit 42 based on the obtained calculation result. AE (automatic exposure) processing and EF (flash pre-emission) processing are performed. Further, the image processing circuit 20 performs predetermined calculation processing using the captured image data, and also performs TTL AWB (auto white balance) processing based on the obtained calculation result.

  The memory control circuit 22 controls the A / D converter 16, the timing generation circuit 18, the image processing circuit 20, the image display memory 24, the D / A converter 26, the memory 30, and the compression / decompression circuit 32. Data from the A / D converter 16 is written into the image display memory 24 or the memory 30 via the image processing circuit 20 and the memory control circuit 22 or directly via the memory control circuit 22.

  The digital camera 100 is provided with an image display memory 24, a D / A converter 26, and an image display unit 28. The image display unit 28 includes a TFT_LCD or the like, and displays the display image data written in the image display memory 24 via the D / A converter 26. The electronic viewfinder function is realized by sequentially displaying the image data captured using the image display unit 28.

  The image display unit 28 can arbitrarily turn on / off the display according to an instruction from the system control circuit 50. When the display is turned off, the power consumption of the digital camera 100 can be greatly reduced.

  The memory 30 is for storing captured still images and moving images, and has a sufficient storage capacity for storing a predetermined number of still images and moving images for a predetermined time. Thereby, in the case of continuous shooting or panoramic shooting in which a plurality of still images are continuously shot, it is possible to write a large amount of images to the memory 30 at high speed. The memory 30 can also be used as a work area for the system control circuit 50.

  The compression / decompression circuit 32 compresses / decompresses image data by adaptive discrete cosine transform (ADCT) or the like, reads an image stored in the memory 30, performs compression processing or decompression processing, and processes the processed data. Write to memory 30.

  The exposure control unit 40 controls the shutter 12 having a diaphragm function, and also has a flash light control function in cooperation with the flash 48.

  The distance measurement control unit 42 controls the focusing of the taking lens 10. The zoom control unit 44 controls zooming of the taking lens 10. The barrier control unit 46 controls the operation of the protection unit 103 that is a barrier.

  The flash 48 has an AF auxiliary light projecting function and a flash light control function. The exposure control unit 40 and the distance measurement control unit 42 are controlled using the TTL method. The system control circuit 50 controls the exposure control unit 40 and the distance measurement control unit 42 based on the calculation result calculated by the image processing circuit 20 using the captured image data.

  A system control circuit 50 controls the entire digital camera 100. The memory 52 stores constants, variables, programs, etc. for operating the system control circuit 50. The display unit 54 includes a liquid crystal display device, a speaker, and the like that display an operation state, a message, and the like using characters, images, sounds, and the like according to execution of a program in the system control circuit 50. One or a plurality of display units 54 are installed at positions in the vicinity of the operation unit of the digital camera 100 that are easily visible, and are configured by a combination of, for example, an LCD, an LED, and a sounding element. The display unit 54 has a part of its function installed in the optical viewfinder 104.

  Among the display contents of the display unit 54, what is displayed on the LCD or the like includes single shot / continuous shooting display, self-timer display, compression rate display, recording pixel number display, recording number display, remaining image number display, shutter speed. Display, aperture value display, exposure compensation display, and the like. In addition, flash display, red-eye reduction display, macro shooting display, buzzer setting display, clock battery level display, battery level display, error display, information display with multi-digit numbers, external recording medium 120 attachment / detachment status display, communication There are I / F operation display, date / time display, etc.

  Among the display contents of the display unit 54, what is displayed in the optical viewfinder 104 includes in-focus display, camera shake warning display, flash charge display, shutter speed display, aperture value display, exposure correction display, and the like.

  The nonvolatile memory 56 is an electrically erasable / recordable memory. As the nonvolatile memory 56, for example, an EEPROM or the like is used.

  The operation unit for inputting various operation instructions of the system control circuit 50 is configured by a single switch or a combination of a switch, a dial, a touch panel, pointing by line-of-sight detection, a voice recognition device, or the like. These operation units will be specifically described.

  The mode dial switch 60 can be set by switching each function mode such as power-off, automatic shooting mode, shooting mode, panoramic shooting mode, playback mode, multi-screen playback / erase mode, and PC connection mode.

  The shutter switch SW1 (62) is turned on during the operation of the shutter button, and starts operations such as AF (autofocus) processing, AE (automatic exposure) processing, AWB (auto white balance) processing, and EF (flash pre-flash) processing. (Start operation before shooting) is instructed. The shutter switch SW1 (62) corresponds to the first switch.

  The shutter switch SW2 (64) is turned on upon completion of the operation of a shutter button (not shown), and instructs to start a series of processing operations (shooting operation start). In this series of processes, an exposure process is performed in which a signal read from the image sensor 14 is written into the memory 30 via the A / D converter 16 and the memory control circuit 22. Further, development processing using computation in the image processing circuit 20 and the memory control circuit 22 is performed. Further, a recording process is performed in which the image data is read from the memory 30, compressed by the compression / decompression circuit 32, and written to the external recording medium 120. The shutter switch SW2 (64) corresponds to the second switch.

  The image display ON / OFF switch 66 sets ON / OFF of the image display unit 28. With this function, when photographing using the optical viewfinder 104, power can be saved by cutting off the current supply to the image display unit 28 including a TFT_LCD or the like.

  The quick review ON / OFF switch 68 sets a quick review function for automatically reproducing image data taken immediately after photographing. Note that the digital camera of this embodiment includes a function for setting the quick review function, particularly when the image display unit 28 is turned off.

  The operation unit 70 includes various buttons and a touch panel. The operation unit 70 includes a menu button, a set button, a macro button, a multi-screen playback page break button, a flash setting button, a single shooting / continuous shooting / self-timer switching button, and the like. Furthermore, menu movement + (plus) button, menu movement-(minus) button, playback image movement + (plus) button, playback image-(minus) button, shooting image quality selection button, exposure compensation button, date / time setting button, etc. There is.

  The power control unit 80 includes a battery detection circuit, a DC-DC converter, a switch circuit that switches blocks to be energized, and the like. The power supply control unit 80 detects the presence / absence of a battery, the type of battery, and the remaining battery level, and controls the DC-DC converter based on the detection result and an instruction from the system control circuit 50, and requires a necessary voltage. It is supplied to each part including the recording medium for a long period. A power supply unit 86 is connected to the power supply control unit 80 via a connector 82 and a connector 84. The power supply unit 86 includes a primary battery such as an alkaline battery or a lithium battery, a secondary battery such as a NiCd battery, a NiMH battery, or a Li battery, an AC adapter, or the like.

  The card controller 90 transmits / receives data to / from an external recording medium 120 such as a memory card. The interface 91 interfaces with an external recording medium 120 such as a memory card. The connector 92 connects the external recording medium 120 such as a memory card and the interface 91. The recording medium attachment / detachment detection unit 98 detects whether or not the external recording medium 120 is attached to the connector 92.

  In the present embodiment, the interface or connector to which the recording medium is attached may be configured with a single or plural interfaces, or any number of systems. Moreover, the structure provided with combining an interface and a connector of a different standard may be sufficient. The interface and the connector may be configured using a PCMCIA card, a CF (Compact Flash (registered trademark), registered trademark) card, or the like that conforms to a standard. Further, when the interface 91 and the connector 92 are configured using a PCMCIA card or a CF (Compact Flash (registered trademark) card or the like conforming to a standard, various communication cards can be connected. Thus, the digital camera 100 can mutually transfer image data and management information attached to the image data to / from peripheral devices such as other computers and printers, etc. As various communication cards, a LAN card, a modem card, etc. USB cards, IEEE 1394 cards, P1284 cards, SCSI cards, communication cards such as PHS, and the like.

  The face detection unit 101 analyzes the image data processed by the image processing circuit 20 and the image data stored in the image display memory 24, and detects an area considered to be a face in the image data. When the face detection unit 101 detects an area that seems to be a face, it outputs the likelihood that it is considered a human face, the position in the input image data, the size, and the like. It is also possible to output the feature amount of each feature point of the detected face. The image comparison unit 102 performs image pattern matching based on color information for the two images recorded in the image display memory 24 and the memory 30, and detects a difference between the images.

  The protection unit 103 is a barrier that prevents the imaging unit from being soiled or damaged by covering the imaging unit including the lens 10 of the digital camera 100.

  The optical viewfinder 104 can take an image using only the optical viewfinder without using the electronic viewfinder function of the image display unit 28. In the optical viewfinder 104, some functions of the display unit 54, for example, a focus display, a camera shake warning display, a flash charge display, a shutter speed display, an aperture value display, an exposure correction display, and the like are installed.

  The photographing operation of the digital camera 100 having the above configuration will be described. 2 and 3 are flowcharts showing the photographing processing procedure of the digital camera 100. FIG. This processing program is stored in the memory 52 and is executed by the CPU in the system control circuit 50.

  The system control circuit 50 checks whether or not the face self-timer photographing mode is set through a menu button or a setting button (not shown) included in the operation unit 70 from the user (step S1).

  When the setting of the face self-timer shooting mode is executed, the system control circuit 50 stores in the memory 52 that the face self-timer shooting mode is set (step S2). On the other hand, if the face self-timer shooting mode is not set, the system control circuit 50 proceeds directly to the process of step S3.

  The system control circuit 50 performs face detection processing by the face detection unit 101 using the image data read from the image sensor 14 or the display data stored in the image display memory 24 as input image data (step S3).

  Here, when a target face is detected from the input image data, it is possible to become a main face from the detected faces by using the accuracy and size of each face output by the face detection unit 101. Select faces. For example, the closer the shape of each of the eyes, nose, mouth and the like is to a standard pattern stored in advance, the higher the certainty. And the higher the probability, the larger the face size, or the closer the face position is to the center of the screen, the higher the point as the main face candidate is set and the highest point is obtained Will be selected as the main face.

  The system control circuit 50 performs the first face number determination process A based on the face information detected in step S3 (step S4). The first face number determination process A will be described later with reference to FIG.

  The system control circuit 50 draws a face frame at a place equivalent to the face position displayed in the live image in the image display memory 24 using the number of faces determined in step S4 and the face information (step S5). . By performing the process of step S5, it is possible to perform a face frame display following the movement of the face position displayed on the live image of the image display unit 28 (see FIG. 5).

  Here, in the first face number determination process A, the threshold value for allowing the face detection unit 101 to recognize a face is set lower than in the second face number determination process B described later. This is because priority is given to the responsiveness of face detection so that the face frame can be immediately tracked even when the face moves.

  The system control circuit 50 monitors whether or not the shutter switch SW1 (62) has been pressed (step S6). If the shutter switch SW1 (62) is not pressed, the system control circuit 50 returns to the process of step S1 and repeats the same process. On the other hand, when the shutter switch SW1 (62) is pressed, the system control circuit 50 performs AF processing (step S7).

  FIG. 4 is a flowchart showing an AF processing procedure in steps S7 and S16. The system control circuit 50 first moves the photographing lens 10 to the scan start position by the distance measurement control unit 42 (step S31).

  Here, scanning refers to moving the photographing lens 10 over a predetermined range and storing a focus evaluation value described later in association with the lens position. This scan start position is set at the infinite end of the focusable area, for example.

  The system control circuit 50 sets a distance measurement frame based on the face position and size detected in step S3 (step S32). The system control circuit 50 converts the analog video signal read from the image sensor 14 into a digital signal using the A / D converter 16 and extracts a high-frequency component of the luminance signal from the output by the image processing circuit 20. This is stored in the memory 52 as a focus evaluation value (step S33). At this time, the system control circuit 50 calculates and stores a focus evaluation value for each distance measurement frame set in step S32 using the video signal in the distance measurement frame.

  The system control circuit 50 acquires the current position of the taking lens 10 and stores it in the memory 52 (step S34). Here, when a stepping motor is used for the distance measurement control unit 42, the position of the photographing lens 10 is determined by the number of relative driving pulses from the initial position detected by a photo interrupter (not shown). The absolute position may be measured using a rotary encoder or the like.

  The system control circuit 50 checks whether or not the current position of the taking lens 10 is equal to the scan end position (step S35). This scan end position is set, for example, at the closest end of the focusable area. If it is not equal to the scan end position, the system control circuit 50 moves the photographing lens 10 by a predetermined amount in the scan end direction (step S36). Thereafter, the system control circuit 50 returns to the process of step S33.

  If it is equal to the scan end position, the system control circuit 50 includes the focus evaluation values of the distance measurement frame set to the main face position (hereinafter referred to as the main face frame) among the focus evaluation values stored in step S33. The maximum one is calculated from (step S37). Note that the main face is determined to be one by determining the position and size of the face from the faces detected in step S3.

  The system control circuit 50 stores the position of the photographing lens 10 (hereinafter referred to as a peak position) when the maximum focus evaluation value calculated in step S37 is acquired in the memory 52 (step S38).

  The system control circuit 50 moves the photographing lens 10 to the peak position stored in step S38 (step S39). Thereafter, the system control circuit 50 returns to the original process.

  When the AF process in step S7 is completed, the system control circuit 50 performs a display for notifying that the AF process is completed as a focused state for the face on which the face frame is displayed in step S5 (step S8). .

  FIG. 5 is a diagram illustrating a captured image in which a face frame is displayed on the image display unit 28. At this time, only the face selected as the main face in step S3 is set with a face frame (main face frame in FIG. 5) having a different display form from the other faces. For example, the face frame of the main face may be green, and the face frames of other faces (ranging frame 0, ranging frame 1 in FIG. 5) may be white. Further, the display form may be changed. For example, the face frame of the main face is drawn with a solid line, and the face frames of other faces are drawn with a dotted line. Further, one or both may blink. When both are blinking, change the blinking cycle so that they can be visually distinguished. Furthermore, the number of frames displayed at the same time may be displayed together to notify the user. In addition, when there is a face in the focusing range other than the main face, a display that shows that the face is in focus may be performed.

  After displaying to the user in step S8, the system control circuit 50 stores the number of faces (number n) determined in step S4 in the memory 52 as a reference value (step S9).

  The system control circuit 50 determines whether or not the shutter switch SW2 (64) has been pressed (step S10). When the shutter switch SW2 (64) has not been pressed, the system control circuit 50 checks whether or not the shutter switch SW1 (62) has been pressed (step S11).

  If the shutter switch SW1 (62) remains pressed, the system control circuit 50 returns to the process of step S10. On the other hand, when the shutter switch SW1 (62) is released, the system control circuit 50 returns to the process of step S1.

  On the other hand, when the shutter switch SW2 (64) is pressed in step S10, the system control circuit 50 checks whether or not the current shooting mode is the face self-timer shooting mode (step S12). If the face self-timer shooting mode is not set, the system control circuit 50 performs shooting processing (step S17). Then, the system control circuit 50 records the photographed image data on the external recording medium 120 or the like (step S18), and ends the photographing process.

  On the other hand, when the current shooting mode is the face self-timer shooting mode in step S12, the system control circuit 50 detects the face detection unit 101 from the image newly obtained by turning on the shutter switch SW2, as in step S3. Then, face detection processing is performed (step S13).

  The system control circuit 50 performs the second face determination process B based on the face information detected in step S13, and determines the number of faces (step S14).

  Here, the difference between the first face determination process A and the second face determination process B will be described. FIG. 6 is a timing chart showing the face detection process, the first face determination process A, and the second face determination process B. When face information is detected by the face detection unit 101 (T1), in the first face number determination process A using this face information, the number of faces is determined using the number of face information detected once. (T2). That is, when three faces are detected from a certain frame image, the number of faces is determined to be “3” as it is. When five faces are detected from the next frame image, the number of faces is “5” as it is. Determined to be. As described above, in the first face number determination process A, the number of faces is determined at high speed by using the detection result as it is in synchronization with the detection result of the face detection unit 101. In step S5, since the face information detected by the face detection unit 101 is used as it is, face detection results can be obtained with high frequency, and the face frame can smoothly follow the face.

  On the other hand, in the face number determination process B executed after the shutter switch SW2 is turned on, chattering is started at the timing (T3) when the face detection unit 101 detects a face, and a predetermined number of detection results (plurality) Result detected) is referenced. In the present embodiment, the predetermined number of times is five. When the number of faces is held, the face is included in the number of faces for the first time (T4).

  That is, only the faces detected by the face detection unit 101 five times consecutively (so-called chatter removal) are counted (counted) as the number of faces. Therefore, even if an unintended person enters the screen, the possibility that the person is detected five times consecutively is very low unless the camera is directly viewed. By performing such processing, detection of an unintended intruder's face and erroneous detection of a face due to background shading are prevented, and erroneous detection at the start of photographing processing (S17) in the face self-timer mode is reduced. It becomes possible. Therefore, a better photograph can be recorded.

  In addition, by instructing the intended subject to look at the camera side in advance, these subjects become relatively easy detection targets for camera face detection. Even if the threshold value is set high, it is considered that no inconvenience occurs.

  The system control circuit 50 determines whether or not the number of faces determined in step S14 exceeds the number of faces (face detection number) n stored in step S9 (step S15). When the number n of faces is not exceeded, the system control circuit 50 returns to the process of step S13 and repeats the same process.

  On the other hand, if the number of faces exceeds n, the system control circuit 50 executes the AF process again (step S16) as in step S7, and proceeds to the photographing process in step S17.

  As described above, according to the digital camera of the present embodiment, when performing self-photographing using the face detection function, it is possible to suppress the start of photographing due to detection of an unintended subject's face. It becomes.

  Further, before the face detection number n as the reference value is stored, priority can be given to the responsiveness of face detection so that even if the face of the subject moves, tracking can be performed immediately. In addition, it is possible to prevent erroneous detection of an unintended intruder's face or face due to a shadow on the background, and to reduce the start of a photographing operation due to erroneous detection.

  In addition, the accuracy of the face detection process after the shutter switch SW2 is pressed can be improved, the erroneous detection due to the face of the passing person, the shadow of the photographing background, etc. can be prevented, and the release without failure can be performed.

  In addition, depending on the shooting mode, it is possible to display only the in-focus status when only the in-focus status is required, and when the face self-timer mode is set, the digital camera detects the in-focus status along with the in-focus status. It is also possible to display so that all faces can be recognized. As a result, the currently detected face can be easily recognized, and it can also be recognized that it is listed as a candidate to which the process is applied when performing a process related to the face.

  The present invention is not limited to the configuration of the above-described embodiment, and any configuration can be used as long as the functions shown in the claims or the functions of the configuration of the present embodiment can be achieved. Is also applicable.

  For example, in the above-described embodiment, an example in which the threshold value of the number of times of continuous detection is switched between the first face number determination process A and the second face number determination process B has been described, but the present invention is not limited to this. Absent. The point is to achieve the object of the present invention by tightening the conditions for counting (counting) the number of faces in the second face number determination process B as compared to the first face number determination process A. Is possible. For example, in the second face number determination process B, a condition that the face to be counted is a face with relatively little movement may be added, or a condition that the face size and orientation are similar. May be added. Thereby, it is possible to detect the face by focusing on the one having relatively little movement or the one having a similar size and direction, and it is possible to prevent erroneous detection of the face.

  In the above embodiment, the target is the face of a person as a subject, but it is needless to say that the target is not limited thereto. For example, it may be the whole body of a person, an animal, or a movable machine.

  In the above embodiment, the shooting operation is started when the number of targets (face detection number) detected after the number of targets (face detection number n) as the reference value is stored is increased. The shooting operation may be started when the number is reduced. Moreover, the increase / decrease number can be set arbitrarily.

  In the above embodiment, a compact digital camera has been described as an example. However, the present invention can also be applied to a digital video camera, a digital SLR (single-lens reflex camera), and the like. Further, a CCD element, a CMOS element, or the like is used as the imaging element.

It is a block diagram which shows the structure of the digital camera in embodiment. 3 is a flowchart illustrating a photographing process procedure of the digital camera 100. 3 is a flowchart showing a shooting processing procedure of the digital camera 100 continued from FIG. 2. It is a flowchart which shows the AF process sequence in step S7 and step S16. It is a figure which shows the picked-up image by which the face frame was displayed in the image display part. 7 is a timing chart showing face detection processing, first face determination processing A, and second face determination processing B.

Explanation of symbols

28 Image Display Unit 50 System Control Circuit 62 Shutter Switch SW1
64 Shutter switch SW2
100 Digital Camera 101 Face Detection Unit

Claims (6)

In an imaging device that captures an image,
Detecting means for detecting a target that satisfies a predetermined condition from the captured image;
Storage means for storing the number of targets detected by the detection means as a reference value;
After the reference value is stored by the storage means, an operation means for starting a predetermined operation when the number of the targets detected by the detection means is different from the reference value,
The image pickup apparatus according to claim 1, wherein the detection unit sets the condition after the reference value is stored more strictly than the condition before the reference value is stored.   When detecting the target from the image, the detection means counts the number of targets detected once before the reference value is stored, and multiple times after the reference value is stored. The imaging apparatus according to claim 1, wherein the condition is set so that the detected target is counted as the number thereof.   The detection means sets the condition so that, when the target is detected from the image, the reference value is stored, and then the target is a target with little movement or a target having a similar size and orientation. The imaging apparatus according to claim 1. A first switch for instructing an operation start before shooting;
A second switch for instructing the start of a shooting operation,
The detecting means detects the target from the image before the reference value is stored before the first switch is pressed,
The storage means stores, as a reference value, the number of the detected objects after the first switch is pressed,
The imaging apparatus according to claim 1, wherein the detection unit detects the target from the image after the reference value is stored after the second switch is pressed. The target is the face of the subject;
Setting means for setting the shooting mode;
The imaging apparatus according to claim 1, further comprising: a display unit configured to display a position and an in-focus state of the detected target, when the set shooting mode is a predetermined mode. . In a control method of an imaging apparatus that captures an image,
A detecting step in which the detection means of the imaging device detects a target that satisfies a predetermined condition from the captured image;
A storage step in which the storage means of the imaging device stores the number of the targets detected in the detection step as a reference value;
After the reference value is stored in the storing step, the operation unit of the imaging device is detected in the detection step according to the condition set strictly compared with the condition before the reference value is stored. And an operation step of starting a predetermined operation when the number of the target objects is different from the reference value.

Images