JP2010026039A - Photographing apparatus, and control method and program of photographing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the defocusing of an image without using any AF auxiliary light source. <P>SOLUTION: When receiving an instruction to normally photograph, a light emission control unit 23 controls a flash 24 to preliminarily emit the light before normal-photographing. An imaging system 9 obtains the pre-emission image obtained by the pre-emission, and a face detection unit 36 detects a face from the pre-emission image. A second AF processing unit 37 performs a focusing operation of the imaging system 9 in accordance with the size of the face detected from the pre-emission image. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an imaging device such as a digital camera, a method for controlling the imaging device, and a program for causing a computer to execute the method for controlling the imaging device.

  In the digital camera, pre-shooting is performed by pressing the release button halfway, AE processing and AF processing are performed using the pre-image acquired by pre-shooting, and exposure preparation and focusing preparation are performed. After that, an image is acquired by the actual shooting in which the release button is fully pressed.

  Here, the AF process is performed by detecting the in-focus position based on the pre-image. As an in-focus position detection method, for example, a TTL method is known that uses the feature that the contrast of an image is high when a desired subject is in focus. Specifically, in the TTL method, a pre-image is divided into a plurality of AF areas, and an image in each AF area is subjected to a filtering process using a high-pass filter to calculate an AF evaluation value for each AF area. The calculation of the value is repeated a plurality of times while moving the focus lens within a predetermined range, and the position of the focus lens that obtained the AF evaluation value with the highest evaluation, that is, the highest output value by the filter, is detected as the in-focus position. It is a method.

  On the other hand, a face detection function is provided in a digital camera, and various processes using the face detection result are performed. For example, a method has been proposed in which a face is detected from a through image acquired before the release button is pressed, and the subject distance is calculated based on the detected face size (see Patent Document 1).

By the way, two images are acquired by shooting without flash emission and shooting with flash emission before the main shooting, and the flash emission amount during the main shooting is controlled using the two images ( That is, a method of flash dimming) has been proposed. Thus, by performing flash light control and controlling the light emission amount of the flash, an image having appropriate brightness can be acquired. Further, there is a method for detecting a face from an image acquired by exposure with light emission, determining a control area for performing flash dimming according to the detected face area, and performing flash dimming using an image in the control area. It has been proposed (see Patent Document 2).
JP 2007-329784 A JP 2005-184508 A

  As described above, in order to perform the TTL AF processing, the minimum subject luminance for detecting the in-focus position is necessary. However, when the minimum subject brightness cannot be obtained, the AF process cannot be performed properly, and there is a problem that an image obtained by shooting is out of focus. The technique described in Patent Document 1 also requires a minimum subject luminance for detecting a face, and a face can be detected for a subject for which the minimum subject luminance cannot be obtained. As a result, the subject distance cannot be calculated.

  In this case, it is conceivable to secure subject brightness by providing an AF auxiliary light source in the camera and irradiating the subject with AF auxiliary light from the AF auxiliary light source. However, in this method, since the AF auxiliary light source needs to be provided in the camera, the cost of the camera increases. Furthermore, since it is necessary to irradiate the subject with AF auxiliary light, the power consumption of the camera also increases.

  The present invention has been made in view of the above circumstances, and an object thereof is to prevent image blurring without using an AF auxiliary light source.

An imaging apparatus according to the present invention includes imaging means for acquiring an image by imaging,
Face detection means for detecting a face from the image;
With flash,
Upon receiving an instruction for main shooting, light emission control means for pre-flashing the flash before the main shooting,
A control means for controlling the photographing means and the face detecting means to acquire a pre-flash image by causing the photographing means to perform pre-flash photographing at the time of the pre-light emission, and to detect a face from the pre-flash image;
And a focusing unit that performs a focusing operation of the photographing unit according to the size of the face detected from the pre-flash image.

  “Main shooting” is shooting for shooting a subject by pressing the release button fully to obtain a main image representing the subject. By pressing the release button halfway, the AE processing and AF processing (the face according to the present invention) is performed. This is different from pre-shooting in which preparations for shooting are performed, which are different from those in which a focusing operation according to the size of the image is performed.

  The “flash” may be a flash built in the photographing apparatus or an detachable external flash.

  As the “face size”, for example, the length of the face in the vertical direction, the length in the horizontal direction, the area of the face, and the like can be used, but when the face is detected by the rectangular area, The length in the horizontal direction and the area of the rectangular area may be the face size. Further, the length or area in the vertical or horizontal direction of the face or rectangular area relative to the length or area in the vertical or horizontal direction of the pre-emission image may be used as the size of the face.

  In the photographing apparatus according to the present invention, when the light emission control unit receives the instruction for the main photographing, the pre-light emission in the non-light-emitting photographing without the light emission to the photographing unit and the pre-lighting is performed before the main photographing. Means for performing flash dimming and performing flash dimming to control the amount of flash emission during the main shooting by performing a calculation based on the non-flash image acquired by the non-flash shooting and the pre-flash image. Good.

Further, in the photographing apparatus according to the present invention, there is provided another focusing unit that divides the pre-image acquired by the pre-shooting into a plurality of regions and performs the focusing operation of the photographing unit based on the AF evaluation value of each region. We shall prepare further,
The control means is means for controlling the photographing means and the face detection means so as to detect a face from the pre-emission image when the focusing operation by the other focusing means cannot be completed, and the focusing The means may be a means for performing a focusing operation of the photographing means according to the size of the face detected from the pre-flash image.

  “Focus operation cannot be completed” means that the subject brightness is low and the AF evaluation value cannot be calculated appropriately, so that the focus position of the focus lens provided in the photographing unit cannot be detected. Means. The AF evaluation value is repeatedly calculated until the in-focus position is detected. However, if the subject brightness is low, the number of AF evaluation value calculations increases, and it may take a long time to detect the in-focus position. is there. In the present invention, it is assumed that the focusing operation cannot be completed even when the AF evaluation value is calculated many times and the detection of the focusing position is not completed within a predetermined time.

An imaging apparatus control method according to the present invention includes an imaging means for acquiring an image by imaging,
With flash,
In the control method of the photographing apparatus provided with the light emission control means for pre-flashing the flash before the main photographing when receiving the instruction of the main photographing,
A pre-flash image is obtained by performing pre-flash shooting with the shooting means during the pre-flash,
A face is detected from the pre-flash image,
The focusing means performs the focusing operation according to the size of the face detected from the pre-flash image.

  In addition, you may provide as a program for making a computer perform the control method of the imaging device by this invention.

  According to the present invention, when a main shooting instruction is received, the flash is pre-flashed before the main shooting, and a pre-flash image is obtained by causing the shooting unit to perform pre-flash shooting during the pre-flash, and the pre-flash image is acquired from the pre-flash image. The face is detected, and the focusing operation of the photographing unit is performed according to the detected face size.

  Here, since the size of the human face has a substantially constant size regardless of the person, the rough distance from the photographing apparatus can be understood by looking at the size. Moreover, the flash is provided in any camera. For this reason, by performing the focusing operation of the photographing unit according to the detected face size, an image without blur can be acquired without providing a special unit such as an AF auxiliary light source in the photographing apparatus. .

  In addition, by using both flash photography and flash photography for pre-flash photography, the flash unit can be used for focusing operation without using flash for focusing operation. Therefore, the focusing operation can be performed efficiently.

  Further, when the pre-image acquired by the pre-photographing is further provided with other focusing means for dividing the pre-image into a plurality of areas and performing the focusing operation of the photographing means based on the AF evaluation value of each area, When the focusing operation of the focusing means cannot be completed, the subject brightness is high by performing the focusing operation of the photographing means according to the size of the face detected from the pre-flash image, and by other focusing means When the in-focus operation can be completed, the in-focus operation of the photographing unit is performed by another in-focus unit with higher accuracy, so that the in-focus operation can be performed with higher accuracy.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 are views showing the appearance of a digital camera 1 to which a photographing apparatus according to an embodiment of the present invention is applied. As shown in FIGS. 1 and 2, a release button 2, a power button 3, and a zoom lever 4 are provided on the top of the digital camera 1.

  The release button 2 has a structure in which two types of operations can be instructed by pressing in two steps. For example, in shooting using an automatic exposure adjustment function (AE: Auto Exposure) and an automatic focus adjustment function (AF: Auto Focus), the digital camera 1 performs a first pressing operation (half-pressing) in which the release button 2 is lightly pressed. (Also called exposure), preparation for shooting such as exposure adjustment and focusing is performed. In this state, when a second pressing operation (also referred to as full pressing) in which the release button 2 is strongly pressed is performed, the digital camera 1 starts exposure and records image data for one screen obtained by the exposure. Record on media.

  On the back of the digital camera 1, a monitor 5 such as a liquid crystal, a mode dial 6 used for setting a photographing mode, and various operation buttons 8 are provided. In the present embodiment, it is possible to set a shooting mode for shooting, a playback mode for playing back an image recorded on a recording medium on the monitor 5, and the like.

  Next, the internal configuration of the digital camera 1 will be described. FIG. 3 is a schematic block diagram showing an internal configuration of a digital camera to which the photographing apparatus according to the embodiment of the present invention is applied. As shown in FIG. 3, the digital camera 1 to which the photographing apparatus according to the present embodiment is applied has an imaging system 9.

  The imaging system 9 includes a photographing lens 10 including a focus lens 10a for focusing on a subject and a zoom lens 10b for realizing a zoom function. Each lens can be moved in the optical axis direction by a focus lens driving unit 11 and a zoom lens driving unit 12 each including a motor and a motor driver. Based on an instruction from a first AF processing unit 28 or a second AF processing unit 37 (to be described later), the focus lens driving unit 11 responds to an instruction from the CPU 40 according to the operation of the zoom lever 4. Based on this, the movement of each lens is controlled. Note that the focus lens 10a and the first AF processing unit 28 constitute other focusing means, and the focus lens 10a and the second AF processing unit 37 constitute the focusing means.

  The diaphragm 14 includes a plurality of diaphragm blades. The aperture drive unit 15 is a small motor such as a stepping motor, and adjusts the position of the aperture blade so that the aperture size of the aperture becomes a size suitable for the purpose according to the aperture value data output from the AE processing unit 29. .

  The shutter 16 is a mechanical shutter and is driven by a shutter driving unit 17. The shutter drive unit 17 controls the opening and closing of the shutter 16 according to a signal generated by pressing the release button and the shutter speed data output from the AE processing unit 29.

  Behind the shutter 16 is a CCD 18 which is an image sensor. The CCD 18 has a photoelectric surface in which a large number of light receiving elements are two-dimensionally arranged, and subject light that has passed through an optical system such as the photographing lens 10 forms an image on the photoelectric surface and is subjected to photoelectric conversion. In front of the photocathode, a microlens array for condensing light on each pixel and a color filter array in which filters of R, G, and B colors are regularly arranged are arranged. The CCD 18 outputs the charge accumulated for each pixel as a serial analog photographing signal line by line in synchronization with the vertical synchronization signal and horizontal synchronization signal supplied from the CCD control unit 19. Note that the charge for one screen is output by the vertical synchronization signal. The time for accumulating charges in each pixel, that is, the exposure time, is determined by an electronic shutter drive signal given from the CCD controller 19. The gain of the CCD 18 is adjusted by the CCD control unit 19 so that an analog imaging signal having a predetermined size can be obtained.

  The analog photographing signal read from the CCD 18 is input to an analog front end (AFE) 20. The AFE 20 includes a correlated double sampling circuit (CDS) that removes noise from the analog signal, an auto gain controller (AGC) that adjusts the gain of the analog signal, and an A / D converter (ADC) that converts the analog signal into a digital signal. It consists of. The image data converted into the digital signal is CCD-RAW data having R, G, and B density values for each pixel.

  The timing generator 21 generates a synchronization signal. By supplying this timing signal to the shutter drive unit 17, the CCD control unit 19, and the AFE 20, the release button is operated, the shutter 16 is opened and closed, and the charge from the CCD 18 is supplied. And the processing of the AFE 20 are synchronized.

  In addition, the digital camera 1 has a flash 24 that emits light when necessary during photographing. The light emission of the flash 24 is controlled by the light emission control unit 23.

  The flash 24 emits light twice in conjunction with the full pressing operation of the release button 2. The first light emission is pre-light emission for measuring the amount of reflected light from the subject, and the amount of light emission is very small compared to normal light emission. In addition to measuring the amount of reflected light, pre-emission has the purpose of preventing red eyes. The second light emission is a main light emission (to obtain an appropriate exposure amount) for supplying sufficient light to the subject for photographing. If the light emission amount of the main light emission is appropriate, an appropriate brightness is obtained. An image can be obtained.

  The light emission control unit 23 performs flash light control. That is, when the release button 2 is fully pressed, a CPU 40 (to be described later) instructs the light emission control unit 23 to start flash dimming, whereby a non-light-emitting image is acquired by non-light-emitting photography without light emission. The The non-luminous image is an image represented by the latest image data stored in the frame memory 26. Furthermore, a pre-flash image is acquired when the flash 24 pre-flashes. The pre-flash image is an image represented by image data stored in the frame memory 26 at the time of pre-flash.

  Then, the light emission control unit 23 calculates the light emission amount of the flash 24 based on the non-light emission image and the pre-light emission image. Specifically, first, the non-light-emitting image and the pre-light-emitting image are divided into a plurality of light control areas, and a difference value of luminance information for each light control area is calculated. FIG. 4 is a diagram showing an example of division into light control areas, and shows a state in which a non-light-emitting image or a pre-light-emitting image is divided into n × m (here 16 × 16 = 256). In the following description, it is assumed that light control areas having different positions are distinguished by symbols such as (1, 1) and (n, m).

  And the light emission control part 23 acquires the non-light-emitting luminance information Ya (1, 1)-Ya (n, m) for every light control area of a non-light-emitting image. For example, the non-luminous image is subjected to RGB-YCC conversion, the luminance value of each pixel is obtained, the average value of the luminance value for each dimming area is obtained, and the non-luminous luminance information Ya is obtained. Also for the pre-emission image, the pre-emission luminance information Yb (1,1) to Yb (n, m) of each dimming area is acquired in the same procedure. Next, the light emission control unit 23 calculates the difference value Yd (x, y) (= Yb (x) between the non-light emission luminance information Ya (x, y) and the pre-light emission luminance information Yb (x, y) for each dimming area. , Y) −Ya (x, y)) is calculated.

  Then, based on the differences Yd (1, 1) to Yd (n, m) of all area blocks, the light emission magnification with respect to the pre-light emission of the flash light emission amount is calculated. For example, a simple average or weighted average Ydm, Yam of the differences Yd (1,1) to Yd (n, m) and the non-luminance luminance information Ya (1,1) to Ya (n, m) is calculated, and the target luminance Yo Is used to calculate the light emission magnification with respect to the light emission amount of the pre-light emission, which is necessary for obtaining the target luminance by the following equation (1).

Luminous magnification = (Yo-Yam) / Ydm (1)
Further, the light emission control unit 23 calculates the light emission time of the flash 24 from the light emission magnification with reference to a lookup table in which the relationship between the light emission time and the light emission magnification is previously associated. The calculated light emission magnification and light emission time are the light emission amount of the flash 24. The lookup table is stored in the internal memory 35.

  The digital camera 1 also has an image input controller 25 that transfers the image data output from the AFE 20 to another processing unit via the data bus 41, and a frame memory 26 that temporarily stores the image data transferred from the image input controller 25. Is provided.

  The frame memory 26 is a working memory used when performing various processes described later on image data. For example, an SDRAM (Synchronous Dynamic Random Access Memory) that performs data transfer in synchronization with a bus clock signal having a constant period. Is used.

  The display control unit 27 displays the image data stored in the frame memory 26 on the monitor 5 as a through image, or displays the image stored on the recording medium 34 on the monitor 5 in the reproduction mode. is there. The through image is taken by the imaging system 9 at predetermined time intervals in synchronization with the vertical synchronization signal generated by the timing generator 21 while the shooting mode is selected.

  The first AF processing unit 28 and the AE processing unit 29 determine shooting conditions based on the pre-image. This pre-image is an image represented by image data stored in the frame memory 26 as a result of the CPU 40 having detected a half-press signal generated by half-pressing the release button causing the CCD 18 to perform pre-photographing. Yes, different from the pre-flash image.

  The first AF processing unit 28 detects the in-focus position of the focus lens 10a based on the pre-image (first AF processing). As a method for detecting the in-focus position, for example, a TTL method for detecting the in-focus position using the feature that the contrast of the image is high when the desired subject is in focus is used. In the TTL method, a pre-image is divided into a plurality of AF areas, an image in each AF area is subjected to a filtering process using a high-pass filter, an AF evaluation value is calculated for each AF area, and an AF evaluation value is calculated. The focus lens 10a is repeatedly moved a plurality of times while moving within a predetermined range, and the position of the focus lens 10a having the highest evaluation, that is, the AF evaluation value with the highest output value from the filter is detected as the in-focus position. This completes the focusing operation.

  Thus, in the first AF process, the calculation of the AF evaluation value is repeated until an appropriate in-focus position is detected. However, when the subject luminance is lower than the predetermined luminance, it is difficult to obtain the maximum value of the AF evaluation value. Therefore, the movement of the focus lens 10a within the predetermined range and the calculation of the AF evaluation value are repeatedly performed. It may take a long time to detect the in-focus position. For this reason, the first AF processing unit 28 has a low subject luminance and cannot calculate the AF evaluation value properly, and therefore cannot detect the in-focus position, or it takes a long time to detect the in-focus position. If the first AF process cannot be completed, such as the case, information to that effect is output to the CPU 40.

  The AE processing unit 29 measures subject brightness based on the pre-image, determines an aperture value, shutter speed, and the like based on the measured subject brightness, and outputs the aperture value data and shutter speed data as exposure setting values (AE). processing).

  The AWB processing unit 30 automatically adjusts the white balance at the time of shooting (AWB processing).

  The image processing unit 31 performs image quality correction processing such as gradation correction, sharpness correction, and color correction on the image data of the main image, and CCD-RAW data as Y data that is a luminance signal and Cb that is a blue color difference signal. YC processing is performed for conversion into YC data comprising data and Cr data which is a red color difference signal. The main image is an image that is captured from the CCD 18 by main shooting executed when the release button is fully pressed and is represented by image data stored in the frame memory 26 via the AFE 20 and the image input controller 25. .

  The compression / decompression processing unit 32 performs a compression process on the image data of the main image processed by the image processing unit 31 in a compression format such as JPEG, and generates an image file. A tag storing incidental information such as shooting date and time is added to the image file based on the Exif format or the like.

  The media control unit 33 accesses a recording medium 34 that is detachably set on a media throttle (not shown), and controls writing and reading of an image file.

  The internal memory 35 stores various constants set in the digital camera 1, a lookup table, a program executed by the CPU 40, and the like.

  The digital camera 1 also includes a face detection unit 36 and a second AF processing unit 37.

  The face detection unit 36 uses a template matching technique, a technique that uses a face discriminator obtained by machine learning learning using a large number of sample images of a face, and the like to create a rectangular region surrounding the face from an image acquired by photographing. (Face region) is detected as a face. Note that the method for detecting a face is not limited to this. For example, a method for detecting a rectangular region having a skin color in an image and surrounding the contour shape of the face as a face, and a region forming the face contour shape as a face. Any method such as a detection method can be used. Further, when a plurality of faces are included in an image acquired by photographing, all faces are detected.

  The face detection unit 36 detects a face from any of the through image, the pre-image, the pre-flash image, and the main image, and the detected face information includes AF processing, flash light control, and face detection. Used for image processing to improve image quality. In particular, when AF processing cannot be completed in the first AF processing unit 28, the face detection unit 36 detects a face from a pre-flash image acquired by flash light control.

  The second AF processing unit 37 performs focusing according to the size of the face detected from the pre-flash image acquired by flash dimming when the AF processing cannot be completed in the first AF processing unit 28. The in-focus position of the lens 10a is determined (second AF process). First, as shown in FIG. 5, the second AF processing unit 37 calculates a ratio F1 / L1 of the vertical length F1 of the face region to the vertical length L1 of the image. Here, since the size of the human face has a substantially constant size regardless of the person, the rough distance from the digital camera 1 to the subject can be understood from the size.

  In the present embodiment, as shown in FIG. 6, a lookup table LUT1 that defines the relationship of the focus position P of the focus lens 10a with respect to the ratio F1 / L1 corresponding to various zoom magnifications is stored in the internal memory 35. The second AF processing unit 37 refers to the lookup table LUT1 and obtains the in-focus position P for the calculated ratio F1 / L1. Then, an instruction for moving the focus lens 10 a to the determined focus position P is output to the focus lens driving unit 11. Thereby, the focusing operation is completed.

  The CPU 40 controls each part of the main body of the digital camera 1 in accordance with signals from various processing units such as the operation button 8 and the first AF processing unit 28.

  The data bus 41 is connected to various processing units, the frame memory 26, the CPU 40, and the like, and exchanges image data and various instructions.

  Next, processing performed in the present embodiment will be described. FIG. 7 is a flowchart showing processing performed in the present embodiment. Note that the present invention is characterized by processing using a pre-flash image acquired by flash dimming. Therefore, in the embodiments described below, the flash dimming will be described.

  The CPU 40 monitors whether or not the release button 2 is half-pressed (step ST1). When the release button 2 is half-pressed, the imaging system 9 performs pre-photographing (step ST2), and the first AF processing is performed. The unit 28 performs the first AF process using the pre-image acquired by the pre-photographing (step ST3). Next, the CPU 40 determines whether or not the first AF process cannot be completed (step ST4). If the determination in step ST4 is affirmative, has the release button 2 been released because the photographer has stopped shooting? It is determined whether or not (step ST5). If step ST5 is affirmed, the process returns to step ST1. If step ST5 is negative, it is determined whether or not the release button 2 is fully pressed (step ST6). If step ST6 is negative, the process returns to step ST5.

  If step ST6 is affirmed, the light emission control part 23 performs flash light control (step ST7). Thereby, the light emission amount of the flash 24 is calculated. In this case, the focus position of the focus lens 10a at the time of flash light control is set to a predetermined position (for example, a position of 1 to 2 m from the camera). Next, the face detection unit 36 detects a face from the pre-flash image acquired by flash dimming (step ST8), and the second AF processing unit 37 performs the second AF process based on the face size (step ST8). Step ST9). Then, the focus lens driving unit 11 moves the focus lens 10a to the focus position determined by the second AF process (focusing operation, step ST10).

  Next, the CPU 40 performs actual photographing (step ST11) and ends the process. In actual photographing, flash emission (main emission) and image acquisition are performed in synchronization under the instruction of the CPU 40. The light emission control unit 23 causes the flash 24 to emit light with the calculated light emission amount at a timing instructed by the CPU 40. Then, the image data of the main image acquired by the main shooting is recorded on the recording medium 34.

  On the other hand, if step ST4 is negative, the CPU 40 determines whether or not the release button 2 has been released when the photographer stops shooting (step ST12). If step ST12 is positive, the process returns to step ST1. If step ST12 is negative, it is determined whether or not the release button 2 is fully pressed (step ST13). If step ST13 is negative, the process returns to step ST12.

  When step ST12 is affirmed, the light emission control part 23 performs flash light control (step ST14). Thereby, the light emission amount of the flash 24 is calculated. In this case, the focus position of the focus lens 10a during flash light control is the focus position detected by the first AF process. Next, the process proceeds to step ST11, where the CPU 40 performs the main photographing and ends the process.

  As described above, in the present embodiment, since the focusing operation is performed according to the size of the face detected from the pre-flash image by the second AF process, special means such as an AF auxiliary light source are used as the photographing apparatus. Therefore, it is possible to obtain an image without blur.

  Further, by performing the second AF process using the image acquired by the pre-emission when performing the flash dimming, the flash dimming can be performed without causing the flash 24 to emit light only for the second AF process. In addition, since the second AF process can be performed, the second AF process can be performed efficiently.

  Further, when the focusing operation of the first AF processing unit 28 cannot be completed, by performing the second AF process, the subject brightness is high and the first AF process can be executed. Since the focusing operation is performed with accuracy, the focusing operation can be performed with higher accuracy.

  In the above embodiment, in the second AF process, a pre-emission image is used by pre-emission when performing flash light control. However, emission of the flash 24 is also performed when red-eye is prevented. For this reason, when the flash 24 is emitted to prevent red-eye without flash dimming, the image pickup system 9 performs shooting, and the image acquired thereby is used as a pre-flash image, and the second AF processing is performed. You may make it perform. Further, the flash 24 may emit light only for the purpose of performing the second AF process.

  In the above-described embodiment, the second AF process is performed when the focusing operation by the first AF process cannot be completed. However, only the second AF process may be performed.

  Moreover, in the said embodiment, a some face may be detected from a pre light emission image. When a plurality of faces are detected in this way, the in-focus position is obtained according to the average size of the plurality of faces, the largest face, the size of the face closest to the center of the image, and the like. What should I do?

  In the above embodiment, the in-focus position is obtained by using the ratio of the vertical length of the face area to the vertical length of the image, but the vertical length of the face area with respect to the vertical length of the image. The focus position may be obtained by using any one of the ratio of the length in the direction, the ratio of the area of the face area to the area of the image, the length in the vertical or horizontal direction of the face area, and the area of the face area. In this case, the look-up table for obtaining the in-focus position is prepared according to the target face parameter such as the ratio of the area of the face area to the area of the image.

  In the above embodiment, the in-focus position is obtained using a look-up table. However, the in-focus position may be obtained by performing calculation according to the zoom magnification.

  As described above, the digital camera 1 according to the embodiment of the present invention has been described. However, the computer functions as a unit corresponding to the face detection unit 36 and the second AF processing unit 37, and the process as illustrated in FIG. The program to be executed is also one embodiment of the present invention. A computer-readable recording medium that records such a program is also one embodiment of the present invention.

The figure which shows the external appearance of the digital camera to which the imaging device by embodiment of this invention is applied (front side) The figure which shows the external appearance of the digital camera to which the imaging device by embodiment of this invention is applied (back side) 1 is a schematic block diagram showing an internal configuration of a digital camera to which a photographing apparatus according to an embodiment of the present invention is applied. The figure which shows an example of the division | segmentation into the light control area Diagram for explaining calculation of face size The figure which shows the look-up table which prescribed | regulated the relationship of the focus position P with respect to ratio F1 / L1 according to various zoom magnifications. A flowchart showing processing performed in the present embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Digital camera 5 Monitor 9 Imaging system 10 Shooting lens 11 Focus lens drive part 23 Light emission control part 24 Flash 28 1st AF process part 36 Face detection part 37 2nd AF process part 40 CPU

Claims (5)

Photographing means for acquiring an image by photographing;
Face detection means for detecting a face from the image;
With flash,
Upon receiving an instruction for main shooting, light emission control means for pre-flashing the flash before the main shooting,
A control means for controlling the photographing means and the face detecting means to acquire a pre-flash image by causing the photographing means to perform pre-flash photographing at the time of the pre-light emission, and to detect a face from the pre-flash image;
An imaging apparatus comprising: a focusing unit that performs a focusing operation of the imaging unit in accordance with a face size detected from the pre-flash image.   Upon receiving the main shooting instruction, the light emission control unit causes the photographing unit to perform non-flash shooting without light emission and pre-flash shooting during the pre-flash before the main shooting, and the non-flash shooting. The flash light control for controlling the amount of light emission of the flash at the time of the main photographing by performing a calculation based on the non-light-emitting image and the pre-light-emitting image acquired by the method according to claim 1. Shooting device. The pre-image acquired by the pre-photographing is further divided into a plurality of areas, and further provided with other focusing means for performing the focusing operation of the photographing means based on the AF evaluation value of each area,
The control means is means for controlling the photographing means and the face detection means so as to detect a face from the pre-flash image when the focusing operation by the other focusing means cannot be completed. 2. The photographing apparatus according to claim 1, wherein the focusing means is means for performing a focusing operation of the photographing means in accordance with a face size detected from the pre-emission image. Photographing means for acquiring an image by photographing;
With flash,
In the control method of the photographing apparatus provided with the light emission control means for pre-flashing the flash before the main photographing when receiving the instruction of the main photographing,
A pre-flash image is obtained by performing pre-flash shooting with the shooting means during the pre-flash,
A face is detected from the pre-flash image,
A method for controlling a photographing apparatus, comprising: performing a focusing operation of the photographing unit according to a face size detected from the pre-emission image. Photographing means for acquiring an image by photographing;
With flash,
Upon receiving an instruction for main shooting, a program for causing a computer to execute a control method of an image pickup apparatus including a light emission control unit that pre-flashes the flash before the main shooting,
A procedure for obtaining a pre-flash image by causing the photographing means to perform pre-flash photographing during the pre-flash;
Detecting a face from the pre-flash image;
A program for causing a computer to execute a procedure for performing a focusing operation of the photographing unit in accordance with a face size detected from the pre-flash image.

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