JP5821413B2 - Imaging device - Google Patents

Description

  The present invention relates to an imaging apparatus.

  There has been known an invention that controls the amount of light emitted from a flash device such as a speedlight to make the exposure at the time of flash imaging appropriate (for example, Patent Document 1).

JP 2001-103367 A

  When controlling the light emission amount of a flash device in an imaging device having a face detection function, it is considered to control the light emission amount so as to be as suitable as possible for the detected face. However, if the speedlight can be freely arranged and illuminated from various angles, as in the case of a light increase system, for example, when illuminating from the side of the subject, the amount of reflected light from the entire face area cannot be taken, so the face area is weighted. There is a problem that the accuracy of the calculation of the light emission amount decreases.

The imaging apparatus according to claim 1 includes an imaging unit that captures a subject image formed by the imaging optical system, a first flash unit for performing main light emission during image shooting with an imaging before preliminary light emission, before imaging preliminary A second flash unit different from the first flash unit that emits light and performs main light emission during imaging, a photometric unit that measures a subject image captured by the imaging unit during preliminary light emission and calculates a photometric value, and an imaging unit A face detection unit that detects a face image from the captured subject image, a first light emission amount control unit that controls a first light emission amount during main light emission in which the main subject is exposed based on a photometric value, and a second When the flash part is caused to emit light, the face image detected by the face detection part is not used, and the second light emission amount during the main light emission is controlled based on the photometric value , the main subject, and the brightness of the background. 2 light emission amount control part.

  According to the present invention, when it is desired to consider the result of face detection, the light emission amount at the time of flash imaging can be controlled to be a light emission amount suitable for the face.

It is a block diagram which shows the example of 1 structure of the imaging device by one embodiment of this invention. It is an example of the flowchart for calculating the light emission amount at the time of the main light emission. It is a figure which shows an example of the determination result of the use determination of a face detection result. It is an example of the flowchart regarding a face detection process. It is an example of the detection result of a face area. It is an example of the figure for demonstrating the distance to a face area | region. It is an example of the figure for demonstrating the size of a face area. It is an example of the flowchart regarding a face area | region selection process. It is an example of the flowchart regarding a face area | region selection process.

  FIG. 1 is a block diagram illustrating a configuration example of an imaging device including a photometric device according to an embodiment of the present invention. The imaging apparatus illustrated in FIG. 1 is a digital single-lens reflex camera, and includes an interchangeable lens 2 and a camera body 3. The interchangeable lens 2 of the camera 1 is attached to the camera body 3 in a replaceable manner by a mount unit (not shown). A remote flash device 5 shown in FIG. 1 together with the camera 1 is an external speedlight controlled by the camera 1. Although only one remote flash device 5 is shown in FIG. 1, a plurality of remote flash devices 5 may exist.

  The interchangeable lens 2 includes an imaging optical system 21 including a focusing lens and a zooming lens, a diaphragm 22, and a lens-side control device 23. The lens side control device 23 includes a CPU, a RAM, a ROM, and the like. The lens-side control device 23 performs processing such as drive control and state detection of the imaging optical system 21 and the aperture 22.

  The camera body 3 includes a quick return mirror 30, a shutter 31, an image sensor 32, a finder screen 33, a pentaprism 34, a re-imaging optical system 35, a photometric sensor 36, an eyepiece lens 37, a body side control device 38, and a display unit 39. An operation member 40, a recording medium 41, and a master flash device 42 are provided.

  A light beam from the subject enters the camera body 3 via the imaging optical system 21. When the quick return mirror 30 is at the illustrated position, the subject light beam incident on the camera body 3 is reflected by the quick return mirror 30 and forms an image on the diffusion surface of the finder screen 33. The light beam transmitted through the finder screen 33 enters the pentaprism 34. The subject luminous flux incident on the pentaprism 34 along the finder optical system optical axis 341 is guided to the eyepiece lens 37 by the pentaprism 34. The subject luminous flux incident on the pentaprism 34 along the optical axis 342 of the photometry optical system is guided to the re-imaging optical system 35 by the pentaprism 34. The re-imaging optical system 35 has a re-imaging lens and re-images the subject light beam incident along the photometric optical system optical axis 342 on the light receiving surface 36 a of the photometric sensor 36. When the quick return mirror 30 is in the retracted state and the shutter 31 is in the open state, the subject luminous flux incident on the camera body 3 is guided to the image sensor 32.

  The image sensor 32 and the photometric sensor 36 have pixels arranged two-dimensionally on their light receiving surfaces. Each pixel has a color filter of red (R), green (G), or blue (B), and is arranged on the light receiving surface based on the Bayer arrangement. When each pixel receives the subject luminous flux, charges are accumulated, and the accumulated charges are read out as a color image signal by the body-side control device 38.

  The body side control device 38 includes a CPU, a RAM, a ROM, and the like, and controls each part of the camera body 3 to execute various processes such as a face detection process. The display unit 39 is a liquid crystal monitor, and reproduces and displays various menu screens and captured images. The operation member 40 is a release switch, a power switch, a function switch, or the like. The recording medium 41 is a detachable recording medium such as a memory card, and records an image related to the subject image captured by the image sensor 32.

  The master flash device 42 includes a flash light emitter 421, a light emission control unit 422 that controls the flash light emitter 421, and a communication unit 423. The remote flash device 5 includes a flash light emitter 51, a light emission control unit 52 that controls the flash light emitter 51, and a communication unit 53. The communication unit 423 and the communication unit 53 can perform wireless communication.

  The body-side control device 38 controls the flash light emitter 421 and the flash light emitter 51 via the light emission control unit 422 and the light emission control unit 52, and performs preliminary light emission before flash imaging and main light emission during flash imaging. For flash imaging performed by the body-side control device 38, a single-flash method in which only the master flash device 42 performs preliminary light emission and main light emission, and in addition to the master flash device 42, the remote flash device 5 also emits light to perform preliminary light emission and main light emission. There is a ramp-up system that performs the above. The body side control device 38 receives the reflected light from the subject at the time of preliminary light emission by the photometric sensor 36, and controls the light emission amount at the main light emission based on the reflected light amount.

  The body-side control device 38 includes at least three light control modes for controlling the light emission amount during the main light emission based on the photometric value (reflected light amount) during the preliminary light emission. The dimming mode can be set via the operation member 40 or the like. In the first dimming mode (referred to as the first dimming mode), the body side control device 38 sets the light emission amount of the main light emission based on the photometric value at the time of the preliminary light emission so that the main subject is appropriately exposed. Control.

  In the second dimming mode (referred to as the second dimming mode), the body-side control device 38 controls the light emission amount of the main light emission in consideration of the balance between the brightness of the main subject and the background. For example, in the second dimming mode, the brightness of the main subject and the background is balanced, so the shutter speed of the shutter 31 is slower than in the first dimming mode. Then, in order to prevent the main subject from being imaged too brightly due to the slow shutter, the light emission amount of the main light emission is corrected to a value smaller than that in the first light control mode.

  In the second dimming mode, when a face area is detected by the face detection process, a third dimming that corrects the light emission amount of the main light emission in consideration of the face area detected by the face detection process It is possible to shift to a mode (referred to as a third dimming mode). In the third dimming mode, the amount of light emitted during the main light emission in the second dimming mode can be corrected so as to be balanced with emphasis on the face area detected by the face detection process. In this correction, the amount of correction varies depending on the size of the target face area (described later). The correction amount when the face area is large is larger than that when the face area is small.

  When the face area is not detected by the face detection process, whether to use the first dimming mode or the second dimming mode is determined via the menu screen displayed on the display unit 39 and the operation member 40. Can be selected by the user. In addition, when the face area is detected by the face detection process and the mode can be shifted to the third dimming mode, the menu screen displayed on the display unit 39 and the operation member 40 are also used. The user may be able to select via

  FIG. 2 is a flowchart relating to the light emission amount calculation process executed by the body side control device 38 to calculate the light emission amount during the main light emission. In step S100, the body-side control device 38 executes a face detection process described later based on the subject image re-imaged on the light receiving surface 36a of the photometric sensor 36. As a result, a face area having a face image is detected from the subject image picked up by the photometric sensor 36, and various information relating to the face area is obtained.

  In step S <b> 200, the body side control device 38 determines whether or not the user has given an imaging instruction via a release switch or the like included in the operation member 40. The body side control device 38 advances the process to step S300 when the user gives an imaging instruction, and advances the process to step S100 when the user does not give an imaging instruction.

  In step S300, the body side control device 38 determines whether or not to use the face detection result. For example, the body-side control device 38 is based on the flash imaging method (one-lamp method or the multiple-light method) of the camera 1 and the dimming mode (first dimming mode or second dimming mode) selected by the user. Whether or not to use the face detection result is determined with reference to a look-up table as illustrated in FIG. The body-side control device 38 advances the process to step S400 when the face detection result is used, and advances the process to step S900 when the face detection result is not used.

  FIG. 3 is an example of a lookup table that the body-side control device 38 refers to for the determination in step S300 of FIG. A lookup table 300 illustrated in FIG. 3 is stored in a ROM or the like of the body-side control device 38, and includes four cells 301a to 301d divided by 2 × 2. The rows of the lookup table 300 are classified according to whether the dimming mode of the camera 1 is the first dimming mode or the second dimming mode. The columns of the lookup table 300 are classified according to whether the flash imaging method is a single-lamp method or a multiple-lamp method.

(A) When the camera 1 is in the first dimming mode and the single lamp system, the body side control device 38 refers to the cell 301a in step S300 and determines that the face detection result is not used.
(B) When the camera 1 is in the first dimming mode and the lighting system, the body side control device 38 refers to the cell 301b in step S300 and determines that the face detection result is not used.
(C) When the camera 1 is in the second dimming mode and the one-lamp system, the body side control device 38 refers to the cell 301c in step S300 and determines to use the face detection result. When it is determined that the face detection result is used, the camera 1 in the second dimming mode can enter the third dimming mode.
(D) When the camera 1 is in the second dimming mode and the lighting system, the body-side control device 38 refers to the cell 301d in step S300 and determines that the face detection result is not used.

  In step S400 of FIG. 2, the body side control device 38 determines whether or not a face area is detected in step S100. When the face area is detected, the body-side control device 38 selects to shift to the third dimming mode, and the process proceeds to step S500. On the other hand, when the face area is not detected, the body-side control device 38 selects not to shift to the third dimming mode but to proceed with the process as the second dimming mode, and advances the process to step S900.

  In step S500 of FIG. 2, the body-side control device 38 performs preliminary light emission and measures the amount of light reflected from the subject including each face area detected in step S100. In step S600, the body-side control device 38 calculates a monitor photometric value RMKao for each face area detected in step S100. For example, the amount of reflected light from the face region under normal light is measured, and the amount of reflected light under normal light is subtracted from the amount of reflected light from the face region during preliminary light emission measured in step S500.

  In step S700, the body-side control device 38 executes a face area selection process described later, and selects one face area to be used for the calculation of the main light emission amount. In step S800, the body side control device 38 controls the light emission amount of the main light emission in consideration of the face area selected in step S700. That is, the light emission amount is calculated by correcting the light emission amount during the main light emission in the second light control mode so that the face area detected by the face detection process is balanced.

  In step S900, the body-side control device 38 performs preliminary light emission and measures the amount of light reflected from the subject. In step S1000, the body-side control device 38 calculates the light emission amount during the main light emission based on the reflected light amount measured in step S900. When the dimming mode is the first dimming mode, the light emission amount of the main light emission is calculated so that the main subject included in the subject image is appropriately exposed. When the light control mode is the second light control mode, the light emission amount of the main light emission is calculated in consideration of the balance between the brightness of the main subject and the background.

  FIG. 4 is an example of a flowchart regarding the face detection process executed in step S100 of FIG. In step S110 of FIG. 4, the body-side control device 38 detects a face area from the subject image re-imaged on the light receiving surface 36a of the photometric sensor 36. When the face area is detected, the body-side control device 38 may set a flag indicating that the face area has been detected. By doing in this way, the process of step S400 of FIG. 2 can be simplified.

  In step S120, the body-side control device 38 assigns a face number that is an ID for identifying each of the face regions detected in step S110. In step S130, the body-side control device 38 calculates the position of the face area detected in step S110. The position of the face area may be, for example, the center position of each face area.

  FIG. 5 is a diagram illustrating an example of a face area detection result. FIG. 5 shows an example of a subject image 360 re-imaged on the light receiving surface 36a of the photometric sensor 36. The subject image 360 includes face areas 361a to 361c. The face area 361a is on the lower left side of the subject image 360, the face area 361b is on the lower center side of the subject image 360, and the face area 361c is on the upper right side of the subject image 360. The face area 361a and the face area 361c are relatively larger than the face area 361b.

  In the case of the subject image illustrated in FIG. 5, face areas 361a to 361c are detected in step S110 of FIG. In step S120, the face number “0” is assigned to the face area 361a, the face number “1” is assigned to the face area 361b, and the face number “2” is assigned to the face area 361c. In step S130, the center positions 362a to 362c of the face areas 361a to 361c are calculated.

  In step S140 of FIG. 4, the body-side control device 38 calculates a distance DistKao from the screen center of the light receiving surface 36a of the photometric sensor 36 on which the subject image 360 is re-imaged to the position of the face area detected in step S130. .

  FIG. 6 is a diagram for explaining the distance DistKao from the screen center of the light receiving surface 36a to the position of the face area detected in step S130. In FIG. 6, a cross-shaped center mark CP is displayed at the center of the screen of the light receiving surface 36 a of the photometric sensor 36. In FIG. 6, distances DistKao0 to DistKao2 from the screen center indicated by the center mark CP to the center positions 362a to 362c of the face areas 361a to 361c are displayed by arrows. In the example of FIG. 6, the distance DistKao1 is smaller than the distance DistKao0 and the distance DistKao2. The distance DistKao0 and the distance DistKao2 are substantially equal.

  In step S150 of FIG. 4, the body side control device 38 calculates the size KaoSize of the face area detected in step S110. For example, the body-side control device 38 draws a square that approximates the shape of the face area detected in step S110, and calculates the length of one side of the square as the size KaoSize of the face area.

  FIG. 7 is a diagram for explaining the size KaoSize of the face area. FIG. 7 illustrates squares 363a to 363c that approximate the shapes of the face regions 361a to 361c. One side of the squares 363a to 363c is adjusted to the shorter dimension of the vertical and horizontal dimensions of each of the face regions 361a to 361c. In FIG. 7, one side of the square 363a is KaoSize0, one side of the square 363b is KaoSize1, and one side of the square 363c is KaoSize2.

  In step S150 in FIG. 4, the body-side control device 38 ends the processing in FIG. 4 after calculating the size of each face area. The face area detected in the process of FIG. 4 and information calculated for the face area (DistKao, KaoSize, etc.) are stored in the RAM or the like of the body-side control device 38, and are referred to in the processes after step S200 in FIG. Is done.

  8 and 9 are examples of flowcharts relating to the face area selection process executed in step S700 of FIG. In step S710 in FIG. 8, the body-side control device 38 has the face photometric value RMKao calculated in step S600 in FIG. 2 out of the face regions detected in step S100 in FIG. 2 is greater than or equal to a predetermined threshold ThVal. For the face area, a maximum size KaoSizeMax that is the maximum value of the size KaoSize of the face area is calculated. Here, the predetermined threshold ThVal is a threshold for removing a face erroneously detected due to noise, and is set in advance in the design stage.

  In step S720 in FIG. 8, the body-side control device 38 has the face photometric value RMKao calculated in step S600 in FIG. 2 out of the face regions detected in step S100 in FIG. 2 is greater than or equal to a predetermined threshold ThVal. A face area having a face area size KaoSize equal to the maximum size KaoSizeMax calculated in step S710 in FIG. 8 is detected, and the number KaoSizeMaxCnt is calculated.

  In step S730 in FIG. 8, the body-side control device 38 determines whether the number KaoSizeMaxCnt calculated in step S720 is 1 or 2 or more. If the number KaoSizeMaxCnt is 1, the body-side control device 38 proceeds to step S740. If the number KaoSizeMaxCnt is 2 or more, the body-side control device 38 proceeds to step S750 in FIG.

  In step S740 of FIG. 8, the body-side control device 38 selects one face area whose face area size detected in step S710 or step S720 is the maximum value KaoSizeMax. Then, the selected face area is output as the processing result of the face area selection process in step S700 of FIG.

  In step S750 in FIG. 9, the body-side control device 38 has the face photometric value RMKao calculated in step S600 in FIG. 2 out of the face regions detected in step S100 in FIG. 2 is greater than or equal to a predetermined threshold ThVal. For the face area, the minimum distance DistKaoMin, which is the minimum value of the distance DistKao from the screen center of the light receiving surface 36a to each face area, is calculated.

  In step S760 of FIG. 9, the body-side control device 38 has the face photometric value RMKao calculated in step S600 of FIG. 2 out of the face regions detected in step S100 of FIG. 2 is greater than or equal to a predetermined threshold ThVal. A face area having a distance DistKao equal to the minimum distance DistKaoMin calculated in step S750 in FIG. 9 is detected, and the number DistKaoMinCnt is calculated.

  In step S770 of FIG. 9, the body-side control device 38 determines whether the number DistKaoMinCnt calculated in step S760 is 1 or 2 or more. When the number DistKaoMinCnt is 1, the body-side control device 38 proceeds with the process to step S780, and when the number DistKaoMinCnt is 2 or more, the body-side control device 38 proceeds with the process to step S790.

  In step S780 of FIG. 9, the body-side control device 38 selects one face area whose distance DistKao detected in step S750 or step S760 is the minimum distance DistKaoMin. Then, the selected face area is output as the processing result of the face area selection process in step S700 of FIG.

  In step S790 of FIG. 9, the body-side control device 38 selects the face number with the smallest face number assigned in step S120 of FIG. Then, the selected face area is output as the processing result of the face area selection process in step S600 of FIG.

According to the embodiment described above, the following operational effects can be obtained.
The camera 1 according to the embodiment of the present invention has a photometric sensor 36 and captures a subject image by the imaging optical system 21. In addition, a master flash device 42 is provided, and preliminary light emission before flash image capturing and main light emission during flash image capturing are performed under the control of the body side control device 38. The photometric sensor 36 measures a subject image during preliminary light emission, and calculates a photometric value. The body-side control device 38 performs a face detection process for detecting a face image from the subject image captured by the photometric sensor 36 (step S100). The camera 1 has a dimming mode called a first dimming mode and a second dimming mode, and sets the dimming mode using the operation member 40 via a menu screen displayed on the display unit 39. Can do. When the first mode is selected, the first light emission amount during the main light emission is calculated based on the photometric value so that the main subject is properly exposed (step S1000). When the second mode is selected, the second light emission amount during the main light emission is calculated based on the photometric value in consideration of the balance between the brightness of the main subject and the background (step S1000). In this way, when considering the result of face detection, it is possible to control the light emission amount at the time of flash imaging so as to be a light emission amount suitable for the face.

The embodiment described above can be implemented with the following modifications.
In the calculation of the size of the face area in step S150 in FIG. 4, the size of the face area is calculated as one side of a square that approximates the shape of the face area. However, the face area may be approximated by a rectangle, and the two sides of the long side and the short side may be calculated as the size of the face area.

  In the face area selection process illustrated in FIG. 8 and FIG. 9, the face area is selected based on the distance to the face area after the face area is selected based on the size of the face area. The face area may be selected based on the size of the face area after the face area is selected based on the face area. Further, the process of detecting the face area where the monitor photometric value RMKao of the face area is equal to or greater than the predetermined threshold ThVal is executed before step S710, and the processes described in FIGS. 8 and 9 are executed only for the detected face area. You may decide to do it. For the selection of the face area based on the distance to the face area after step S750, the face area of which the size KaoSize of the face area detected in step S720 is not the face area detected in step S100 of FIG. 2 is the maximum size KaoSizeMax. A face area may be selected from the list. Further, in S790 of FIG. 9, when the face area cannot be selected as a single by the face area size KaoSize and the distance DistKao to the face area, the face area is selected based on the face number, but the face area is selected at random. Alternatively, a plurality of face areas may be selected.

  In step S300 of FIG. 2, the lookup table 300 is referred to, but other methods may be used. For example, the body-side control device 38 executes a determination as to whether or not the dimming mode is the second dimming mode and a determination as to whether or not the flash imaging method is the single-lamp method, and the determination results are The face detection result may be used only when both are determined to be positive.

  The embodiment and each modification described above are merely examples, and the present invention is not limited to these contents as long as the features of the invention are not impaired.

DESCRIPTION OF SYMBOLS 1 Camera 2 Interchangeable lens 3 Camera body 5 Remote flash device 21 Imaging optical system 22 Aperture 23 Lens side control device 30 Quick return mirror 31 Shutter 32 Image sensor 33 Viewfinder screen 34 Penta prism 35 Re-imaging optical system 36 Photometric sensor 36a Light reception Surface 37 Eyepiece 38 Body side control device 39 Display unit 40 Operation member 41 Recording medium 42 Master flash device 300 Look-up table

Claims (6)

An imaging unit for imaging a subject image by an imaging optical system;
A first flash unit that performs an imaging main light emission during the previous preflash and IMAGING,
A second flash unit different from the first flash unit, which performs preliminary emission before imaging and main emission at the time of imaging;
A photometric unit that measures a subject image captured by the imaging unit at the time of the preliminary light emission and calculates a photometric value;
A face detection unit that detects a face image from a subject image captured by the imaging unit ;
A first light emission amount control unit for controlling a first light emission amount at the time of the main light emission in which the main subject is exposed based on the photometric value;
When the second flash unit is caused to emit light, the face image detected by the face detection unit is not used, and the second light emission at the time of the main light emission is based on the photometric value, the main subject, and the brightness of the background. A second light emission amount control unit for controlling the light emission amount of
That includes a imaging device. The imaging device according to claim 1,
The second light emission amount control unit is configured to perform the second light emission during the main light emission based on the photometric value and the face image detected by the face detection unit, and based on the brightness of the main subject and the background. An imaging device that controls the amount. The imaging device according to claim 1 or 2,
A setting unit for setting a dimming mode from among a plurality of dimming modes for controlling the light emission amount during main flash;
A switching unit that switches the light emission amount control during the main light emission between the first light emission amount control unit and the second light emission amount control unit according to the light control mode set by the setting unit;
An imaging apparatus further comprising: In the imaging device according to any one of claims 1 to 3 ,
A second imaging unit that images a subject image by the imaging optical system and generates an image for recording;
A recording unit for recording the recording image;
It said imaging a subject image that has passed through the optical system, further Ru comprising an imaging device and a light guide portion for guiding the said imaging unit and the second imaging unit. An imaging unit for imaging a subject image by an imaging optical system;
A first flash unit that performs an imaging main light emission during the previous preflash and IMAGING,
A second flash unit different from the first flash unit, which performs preliminary emission before imaging and main emission at the time of imaging;
A photometric unit that measures a subject image captured by the imaging unit at the time of the preliminary light emission and calculates a photometric value;
A face detection unit that detects a face image from a subject image captured by the imaging unit ;
A selection unit for selecting the first mode, the second mode, and the third mode;
A first calculation unit that calculates a first light emission amount during the main light emission in which the main subject is exposed based on the photometric value when the selection unit selects the first mode;
When the second mode by the selection unit is selected, and the photometric value, based on the brightness of the main object and the background, a second calculation unit for calculating a second light emission amount at the time the main flash ,
When the third mode by the selection unit is selected, the correction unit on the basis of the face detection unit detects a face image, calculates a third light emission amount by correcting the second light emission amount,
With
When the correction unit causes the second flash unit to emit light, the correction unit does not correct the second light emission amount even when the third mode is selected by the selection unit.
It said first flash unit, when the first mode by the selection unit is selected performs main emission on the basis of the first light emission amount, when the second mode by the selection unit is selected When performing the main light emission based on the second light emission amount and causing the second flash unit to emit light, it is based on the second light emission amount even when the third mode is selected by the selection unit. An imaging device that performs main light emission . The imaging apparatus according to claim 5 ,
A second imaging unit that images a subject image by the imaging optical system and generates an image for recording;
A recording unit for recording the recording image;
It said imaging a subject image that has passed through the optical system, further Ru comprising an imaging device and a light guide portion for guiding the said imaging unit and the second imaging unit.

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