JP5887759B2 - Imaging apparatus and imaging method - Google Patents

Description

  The present invention relates to an imaging apparatus and an imaging method.

  Conventionally, among the digital cameras that perform TTL dimming, information on the reflectance of the subject is obtained by calculating from the reflected light photometry result at the time of preliminary light emission and the subject distance information from the photographing lens or the focus detection unit, There is one aiming to emit main light with an appropriate amount of light. These cameras obtain information (reflectance information) such as whether the subject is a subject having a standard reflectance, a subject with low reflection, or a subject with high reflection, and so on. The light control area divided from the information is weighted, and the light emission amount calculation for the main light emission is performed.

Japanese Patent No. 4389546

  In a general flash automatic flash mode, when the brightness difference between the main subject and the surroundings is large, it is determined that the backlight is backlit, and the built-in flash is popped up to perform daytime synchronization automatically. In this case, when the background is bright and the main subject is dark, the main subject can be shot with the appropriate exposure, whereas when the surrounding is dark and the main subject is bright, the main subject is set to an appropriate exposure. Since the flash is emitted, the main subject may fly white. This phenomenon may also occur when a photographer accidentally takes a picture with a flash during the day (including manual flash photography). Note that the brightness of the main subject can be brought close to the appropriate exposure by reducing the brightness of the entire screen. However, in this case, ambient brightness is also lowered.

One aspect of the imaging device to illustrate the present invention, an imaging apparatus that performs preliminary light emission prior to main light emission during flash photography, a light measuring means for outputting a photometric signal by metering the reflected light of the subject, the photometric signal a main object detecting unit that detects a main subject area based, with is that photometric signal obtained from the photometric means before or after the preliminary light emission, metering the main subject detection means is metering the main subject area detected the value is compared with the exposure value set when performing the shooting, when the main subject region is determined to high exposure to the peripheral area, the exposure to reduce the amount of light emitted at the main light emission And a main light emission amount correcting means for under-correcting.

  According to the present invention, it is possible to reliably bring the main subject close to an appropriate exposure without changing the ambient brightness during flash photography.

1 is a block diagram illustrating an outline of a single-lens reflex electronic camera according to an embodiment of the present invention. It is a block diagram which shows the structure of the control part demonstrated in FIG. It is a flowchart explaining the operation | movement procedure of the flash photography mode of a single-lens reflex electronic camera. 4 is a flowchart for explaining a continuation of the operation procedure described in FIG. 3. It is a timing chart explaining the drive timing of each part of a single-lens reflex electronic camera. It is explanatory drawing which shows the pixel arranged in the matrix form on the photometry surface of the photometry sensor. It is explanatory drawing which shows each photometry area | region which performs division | segmentation photometry at the time of preliminary light emission. 6 is a graph for determining a weighting coefficient between a face area reflected light amount photometric value (photometric value B) and a full screen reflected light amount (photometric value A) used in calculating the main light emission amount according to the face size. It is explanatory drawing which demonstrates virtually the face detection frame which scanned the full screen of the photometry signal and detected the face image area | region. It is a graph for calculating | requiring the main light emission correction value which is a weighting element at the time of correct | amending main light emission amount based on a face area exposure deviation value. It is a graph for calculating | requiring the peripheral luminance correction coefficient which is an element of weighting when correct | amending this light emission amount based on a full screen stationary light photometric value.

  A single-lens reflex electronic camera (imaging device) 10 exemplifying one embodiment of the present invention includes a replaceable photographing lens 11, an aperture 12, a main mirror 13, a sub mirror 14, a focusing plate 15, a condenser lens 16, a pentaprism 18, an eyepiece. Lens 19, focal plane shutter (hereinafter referred to as “shutter”) 20, lens driving mechanism 22, aperture driving mechanism 23, mirror driving mechanism 24, distance measuring unit 25, shutter driving mechanism 26, imaging unit 21, and A / I for imaging D27, image capturing buffer memory 28, image capturing image processing unit 29, recording unit 30, operation unit 31, photometric unit 32, photometric A / D 33, photometric buffer memory 34, photometric image processing unit 35 , A face detection unit 36, a memory 37, a photometric value calculation unit 38, a flash control unit 39, a flash light emission unit 40, etc. It is generally controlled by one. The control unit 41, the image processing unit 29 for photographing, the recording unit 30, the image processing unit 35 for photometry, the face detection unit 36, the memory 37, and the photometric value calculation unit 38 are connected to the bus 42.

  The operation unit 31 includes a power switch, a release button, a mode selection operation unit, and the like. The mode selection operation unit is for selecting either the normal shooting mode or the flash shooting mode. In flash photography mode, preliminary light emission is performed before the main light emission.

  The flash control unit 39 controls preliminary light emission and main light emission based on the result of the preliminary light emission. The flash light emitting unit 40 and the flash control unit 39 constitute a built-in flash that compensates for the amount of light when light such as natural light is insufficient. This built-in flash can adjust the light quantity of the flash. In shooting in a dark place or in a dark subject, the flash shooting mode is entered even in the normal shooting mode. In flash photography, the control unit 41 calculates the main light emission amount based on the reflected light amount of the subject obtained during preliminary light emission, transmits a flash light emission signal including information on the main light emission amount to the flash control unit 39, and the flash control unit 39. However, the flash light emitting unit 40 emits light with the light emission amount to brighten the subject.

  The mirror driving mechanism 24 has a mirror-up position where the subject light passing through the photographing lens 11 is imaged on the imaging surface of the imaging unit 21 and a focusing plate disposed on a focal plane conjugate with the imaging surface in the finder optical path. The main mirror 13 is moved between the mirror-down position where the image is formed on the mirror 15.

  The lens driving mechanism 22 moves the photographing lens 11 in the optical axis direction to focus on the subject. A part of the main mirror 13 is a half mirror. The sub mirror 14 reflects the subject light beam incident from the half mirror and guides it to the distance measuring unit 25. The distance measuring unit 25 detects a phase difference signal from the incident subject luminous flux and sends the phase difference signal to the control unit 41 as a defocus amount with respect to the subject distance. The control unit 41 controls the lens driving mechanism 22 based on the defocus amount to move the photographing lens 11 to the in-focus position. The sub mirror 14 retracts from the optical axis in conjunction with the movement of the main mirror 13 to the mirror up position.

  The imaging unit 21 is an imaging sensor (CMOS sensor or CCD sensor) for capturing an image for recording. As is well known, the image sensor is provided with a Bayer array color filter (single-plate color filter) in front of the imaging surface.

  The imaging unit 21 captures a subject image and sends an image signal to the imaging A / D 27. The imaging A / D 27 converts the image signal into a digital image signal and temporarily stores it in the imaging buffer memory 28. The image signal read from the buffer memory 28 is sent to the image processing unit 29 for imaging. The image processing unit 29 performs processing such as white balance, RGB pixel interpolation, and YUV conversion on the image signal to generate recording image data, and sends the recording image data to the recording unit 30. The recording unit 30 records image data for recording.

  The photometric unit 32 includes an imaging optical system including an imaging lens 43, a prism 44, and the like, and a photometric sensor 45, which are arranged on the pentaprism 18. The imaging optical system re-images the subject image formed on the focusing screen 15 on the photometric surface of the photometric sensor 45. The subject image that passes through the photographing window 57 and the photographing lens 11 in order is formed on the focusing screen 15 after being reflected by the main mirror 13 set at the mirror down position. The subject image formed on the focusing screen 15 is transmitted through the pentaprism 18 through the condenser lens 16 to be converted into an erect image, magnified by the eyepiece lens 19, and observed through the viewfinder eyepiece window 58. The subject image formed on the focusing screen 15 forms an image on the photometric surface of the photometric sensor 45 via the condenser lens 16, the pentaprism 18, and the imaging optical systems 43 and 44.

  The photometric signal obtained from the photometric sensor 45 is digitally converted by the photometric A / D 33 and then temporarily stored in the photometric buffer memory 34. The photometric signal read from the photometric buffer memory 34 is interpolated into a photometric signal for each RGB by the photometric image processing unit 35, and then a luminance signal is generated from the photometric signal for each RGB. This luminance signal is temporarily stored in the memory 37. In the photometric sensor 45, photoelectric conversion elements (pixels) composed of, for example, a CMOS or a CCD are two-dimensionally arranged. The photometric sensor 45 is driven according to the control of the control unit 41. The photometric sensor 45 is provided with a Bayer array color filter (single plate color filter) in front of the photometric surface. As the photometric signal output from the photometric sensor 45, a photometric signal obtained from a pixel in a photometric area of a small size except for the periphery of the photometric surface, which is substantially the same as the imaging area, is used. The photometric signal obtained from the pixels in the photometric area is converted into a digital photometric signal by the photometric A / D 33 and then temporarily stored in the buffer memory 34. The photometric signal read from the buffer memory 34 is sent to the image processing unit 35 for photometry.

The photometric image processing unit 35 interpolates the Bayer array photometric signals into RGB photometric signals and performs processing such as extracting a luminance signal (Y) from the RGB photometric signals.
The face detection unit 36 detects a human face image region (main subject region) based on the luminance signal (Y) described above. Instead of the luminance signal, face detection may be performed based on a photometric signal of one color component among the three RGB color components, for example, a G color component. As the color filter in this case, a color filter including two G filters in each column and each row constituting the matrix is preferable.

  The memory 37 updates and stores information such as the photometric signal and luminance signal for each RGB obtained from the photometric image processing unit 35 and the position and size (size) of the face image area detected by the face detection unit 36. The The photometric value calculation unit 38 calculates a photometric value based on the luminance signal stored in the memory 37.

  When the release button is fully pressed in the flash photographing mode, the control unit 41 controls the flash control unit 39 to perform preliminary light emission. The control unit 41 causes the photometric sensor 45 to perform an accumulation operation in accordance with the preliminary light emission of the flash light emitting unit 40. The signal obtained by the accumulation operation is input to the photometric A / D 33 as described above.

  The control unit 41 controls the main flash for the flash control unit 39 based on the TTL dimming calculation result. Hereinafter, the charge accumulation operation performed by the photometric sensor 45 during preliminary light emission is referred to as preliminary light emission photometry. Further, the charge accumulation operation performed by the photometric sensor 45 when no light is emitted is referred to as steady-state photometry.

As shown in FIG. 2, the control unit 41 includes a calculation unit 50, a determination unit 51, a main light emission amount calculation unit 52, a main light emission amount correction unit 53, and a re-preliminary light emission processing unit 54.
In order to calculate the main light emission amount corresponding to the subject reflected light amount, the calculation unit 50 performs an operation of removing (subtracting) the steady light amount, that is, the steady light metering value representing the steady light component of the subject from the preliminary light metering value Subtraction process). The photometric value obtained after the subtraction process is called the reflected light amount photometric value.

The determination unit 51 determines whether the photometric result of the photometric sensor 45 and the preliminary light emission photometric value satisfy a predetermined condition. When the preliminary light emission metering value exceeds a predetermined threshold value, it is determined that the light emission amount during the preliminary light emission is large, and a re-emission signal is sent to the re-preliminary light emission processing unit 54. The re-preliminary light emission processing unit 54 controls the flash control unit 39 so as to reduce the light emission amount and execute the preliminary light emission again. Conversely, when the photometric value is less than the threshold value, the determination unit 51 drives the main light emission amount calculation unit 52.
The main light emission amount calculation unit 52 calculates the light emission amount during the main light emission of the flash based on the reflected light amount photometric value.

By the way, the preliminary light emission is performed with an open aperture. For this reason, the above-described main light emission amount may be different from the aperture value at the time of shooting. The main light emission amount correcting unit 53 corrects the main light emission amount based on the aperture value and ISO sensitivity at the time of shooting. Then, the main light emission amount correcting unit 53 controls the flash control unit 39 to execute the main light emission based on the corrected main light emission amount. Note that preliminary light emission may be performed by driving the aperture to an aperture value with proper exposure.
Further, after the aperture correction, the main light emission amount correction unit 53 corrects the main light emission amount in accordance with the face area exposure deviation value.

  The face area exposure deviation correction is performed by the exposure value BVAPEX for the steady light exposure calculated using the steady light metering value obtained from the photometry unit 32 before the release button is fully pressed, and the face detection unit 36 used in the main light emission amount calculation. This is done by comparing the exposure values of the detected face image areas. As a result of the comparison, when the exposure value of the face image area is large, it is determined that the subject is in the front light. When the subject is in direct light, flash exposure tends to be overexposed, so the main flash quantity is undercorrected. Then, the main light emission amount correcting unit 53 controls the flash control unit 39 to execute the main light emission based on the corrected main light emission amount.

  Next, the operation of the above configuration will be described with reference to the drawings. 3 and 4 are flowcharts for explaining the operation procedure in the flash photographing mode of the single-lens reflex electronic camera. First, after the power button is turned on (S-1), the flash shooting mode is selected (S-2). Here, it is confirmed in order whether the shutter 20 is set at the closed position and whether the main mirror 13 is set at the mirror-down position. If neither is set, the closed position and the mirror down position are forcibly set.

  FIG. 5 is a timing chart for explaining the drive timing of each part of the single-lens reflex electronic camera. When the flash photographing mode is selected, the control unit 41 drives the photometric sensor 45 at time t1 shown in FIG. Before the release button is fully pressed, that is, before a shooting instruction operation is performed by the user, the photometric sensor 45 performs constant light metering at predetermined intervals. A photometric value obtained by this constant light metering is called a steady light metering value. Based on the steady light metering value, the control unit 41 calculates a proper exposure value BVans related to the steady light exposure using a known metering method (multi-pattern metering method or the like), and determines an aperture value and a shutter speed. The steady light metering value and the steady light exposure value BVans are updated every predetermined period and stored in the memory 37.

  The luminance signal is read from the memory 37 and sent to the face detection unit 36. The face detection unit 36 detects the position and size of the face image area based on the luminance signal at time t2. The position and size of the detected face image area are stored in the memory 37. Thereafter, until the shutter release is performed, the series of cycles from the photometry to the face detection / storage described above are repeated at a predetermined cycle (S-3). Therefore, the memory 37 always stores the latest luminance signal and the position / size of the face image area.

  The control unit 41 monitors the half-press operation of the release button (S-4), and executes the shooting preparation operation in response to the half-press operation being performed (S-5). In the shooting preparation operation, the distance measuring unit 25 is driven, and the lens driving mechanism 22 is controlled based on the defocus amount obtained from the distance measuring unit 25 to move the shooting lens 11 to the in-focus position, and is stored in the memory 37. The light value is obtained based on the full screen steady light photometric value calculated by the photometric value calculation unit 38 based on the luminance signal and the ISO sensitivity set at that time, and the exposure value is set so as to be the obtained light value. decide. As the exposure value, a new value is stored in the memory 37 for each half-press operation.

  The control unit 41 monitors whether the full-press operation (shooting instruction operation) is performed as it is from the half-press operation state (S-6), and when the user performs the shooting instruction operation at time t3, the digital camera The ten control units 41 output a preliminary light emission instruction signal for instructing preliminary light emission to the flash control unit 39 (S-7). When the preliminary light emission instruction signal is input, the flash control unit 39 causes the flash light emission unit 40 to perform preliminary light emission at a predetermined preliminary light emission amount at time t4. As a result, as shown in FIG. 5, the flash light emitting unit 40 performs preliminary light emission in the accumulation time Δt.

  When the preliminary light emission instruction signal is output by the flash control unit 39, the control unit 41 causes the photometric sensor 45 to accumulate charges in the period Δt while the flash light emission unit 40 is emitting light. In this case, the photometric sensor 45 emits light from the flash light emitting unit 40, is reflected by the subject, and enters through the photographing lens 11 (subject reflected light amount) and ambient light (steady light) of the subject. A charge signal corresponding to the above is output to the A / D 33. The photometric value calculating unit 38 calculates a preliminary light emission photometric value from the preliminary light emission photometric result (S-8).

  Immediately after the preliminary light metering is performed, that is, after the sweeping out of the charges accumulated by the preliminary light metering is completed, the control unit 41 causes the photometric sensor 45 to accumulate charges in the period Δt at time t5 ( S-9). In other words, the photometric sensor 45 accumulates charges for a period Δt following the preliminary light metering. The period Δt is the same as the preliminary light metering time. In this case, the photometric sensor 45 sends a charge signal to the A / D 33 according to the amount of light incident through the photographing lens 11 when no light is emitted, that is, the amount of stationary light that is ambient light of the subject. Output. The photometric value calculation unit 38 calculates a steady light photometric value from the steady light photometric result (S-10).

  At time t6, the calculation unit 50 calculates the total screen reflected light amount photometric value (photometric value A (second photometric value of the present invention)) and face area reflected light amount photometric value (photometric value B (first photometric value of the present invention)). ) Is calculated (S-11).

First, calculation of the full screen reflected light amount photometric value (photometric value A) will be described.
As shown in FIG. 6, since the photometric sensor 45 includes a plurality of pixels (photoelectric conversion elements) arranged in a matrix, the preliminary light-emission photometric value also includes a plurality of data. In this embodiment, the preliminary light emission photometric value is divided into five areas as shown in FIG. These photometric values are referred to as 5-split preliminary emission photometric values (photometric values C [i]). i is 0-4. Each of the five-split preliminary emission photometric values (photometric values C [i]) is calculated from the average value. The number of divided regions is not limited to “5”, and any number of divided regions may be used.

  In addition, a 5-division stationary light metering value (photometric value D [i]) is calculated from the stationary light metering value acquired immediately after the preliminary light emission. The calculation method is the same as the five-split preliminary light-emission photometric value (photometric value C [i]). Next, the stationary light component is removed by subtracting the 5-split stationary light photometric value (photometric value D [i]) from the 5-split preliminary light metering value (photometric value C [i]). The obtained photometric value is defined as a five-part reflected light amount photometric value (photometric value E [i]). Then, a full screen reflected light amount photometric value (photometric value A) is calculated from the five-divided reflected light amount photometric value (photometric value E [i]). In this embodiment, (photometric value E [i]) is calculated by weighting and synthesizing. An example of weighting at this time is described in [Equation 1].

[Equation 1]
Photometric value A = 0.33 * E [0] + 0.16 * E [1] + 0.16 * E [2] + 0.16 * E [3] + 0.16 * E [4]

The calculation of the face area reflected light amount photometric value (photometric value B) will be described.
From the preliminary light emission photometric value, the photometric value in the face image area detected by the face detection unit 36 before the preliminary light emission and the face area preliminary light emission photometric value (photometric value F) are calculated. As the face image area at this time, position information of the face image area detected before the preliminary light emission and stored in the memory 37 is used. A face area steady light photometric value (photometric value G (“photometric value” of the present invention)) is calculated from the steady light photometric value obtained immediately after the preliminary light emission. The calculation method is the same as the face area preliminary light emission photometric value (photometric value F). The face area reflected light photometric value (photometric value B) is calculated by subtracting the face area stationary light photometric value (photometric value G) from the face area preliminary light emission photometric value (photometric value F).

  The determination unit 51 compares the photometric value F with the threshold value H (S-12). As a result of the comparison, when the photometric value F exceeds the threshold value H, that is, when the luminance value of the face image area is saturated, the light amount The preliminary light emission processing unit 54 is controlled so that preliminary light emission is executed again by lowering (S-13).

  The determination unit 51 drives the main light emission amount calculation unit 52 when the photometric value F is less than the threshold value H, that is, when the luminance value of the face image region is not saturated. The main light emission amount calculation unit 52 reads the full-screen reflected light amount photometric value (photometric value A) stored in the memory 37 at the time t7, and based on the read photometric value A and the photometric value B. Then, the main flash amount is calculated (S-14). Here, the reflected light metering value for calculating the main light emission amount used for calculating the main light emission amount is obtained using the equation described in [Equation 2].

[Equation 2]
RMmain = (1.0−K) × RMField + K × RMKao
RMmain is a reflected light photometric value for calculating the amount of emitted light, RMField is a photometric value A, RMKao is a photometric value B, and K is a coefficient of “1” or less.

  The reflected light photometric value (RMmain) for main light emission amount calculation is calculated by changing the weighting coefficient K between the photometric value A and the photometric value B as shown in [Equation 2]. As shown in FIG. 8, the weighting coefficient K is determined according to the size of the face image area (face detection frame 55) detected by the face detection unit. That is, as the face size increases, the value of the coefficient K is brought closer to “1” and the photometric value B is weighted higher than the photometric value A to obtain the reflected light photometric value for the main light emission amount calculation.

  As shown in FIG. 9, the face size at this time is the length of the face detection frame 55 when a face image is detected. The coefficient K is “1” when the vertical length of the entire screen and the face detection frame 55 are substantially the same. The coefficient K is a coefficient corresponding to the vertical length of the face detection frame 55 with respect to the entire screen because the face detection frame 55 is square. However, when the face detection frame 55 is circular, rectangular, or triangular, Alternatively, a coefficient corresponding to the horizontal length, area, or the like may be used.

  The main light emission amount correcting unit 53 corrects the main light emission amount according to the aperture value and ISO sensitivity (aperture correction) at time t8 (S-15). At this time, if the aperture value is a value that cannot be set in the aperture 12, the ISO sensitivity is changed. In this case, the main light emission amount correcting unit 53 corrects the main light emission amount according to the changed ISO sensitivity in addition to the aperture value.

  Thereafter, the main light emission amount correction unit 53 performs face area exposure deviation correction after aperture correction. This face area exposure deviation correction is performed by measuring the face image area detected by the face detection unit 36 before the preliminary light emission using the steady light metering signal obtained from the photometry unit 32 after the preliminary light emission (at time t5). The face area steady light metering value (metering value G) is compared with the exposure value that is set when shooting is actually performed to determine whether the face image area is overexposed relative to the surrounding area. (S-16) When it is determined that the face image area is overexposed, the amount of light emitted during the main light emission is reduced to undercorrect the exposure (S-17). If the exposure is not overexposed, the under correction is not performed. Further, the steady light metering signal for metering the face region steady light metering value may be a signal obtained from the light metering unit 32 before preliminary light emission (for example, at time t1).

  As a specific example of under-correction, the face area exposure deviation value (ObjdDC) is obtained by subtracting the light value from the equation described in [Equation 3], that is, the photometric value C.

[Equation 3]
ObjdDC = BVKao-BVAPEX
ObjdDC is a face area exposure deviation value, and BVAPEX is an exposure value (light value corresponding to exposure and ISO sensitivity) that is set at the time of actual photographing, and is obtained from the relationship of the APEX system (AV + TV-SV). BVKao is a face region stationary light photometric value.
At the time of manual flash photography, the light value corresponding to the manually set exposure and ISO sensitivity is BVAPEX.

  Thereafter, a correction value (main light emission correction value: ObjBLHo) for the main light emission amount is obtained from the face area exposure deviation value (ObjdDC). As shown in FIG. 10, the main light emission correction value (ObjBLHo) is determined from the face area exposure deviation value (ObjdDC) to determine whether the face is dark, half-backlit, or brightly forward-lit. Thus, the face area exposure deviation value (ObjdDC) changes from the minus side to the plus side (the state of the face area changes from the half backlight to the normal light) in response to the change from the half backlight to the normal light. Accordingly, the light emission amount during the main light emission is decreased.

  Here, the main light emission amount correction unit 53 weights the main light emission correction value (ObjBLHo) according to the peripheral luminance. Specifically, a full screen obtained by metering the entire screen using a steady light metering signal obtained from the photometry unit 32 before preliminary light emission (for example, at time t1) or after preliminary light emission (at time t5). Based on the steady light photometric value (BVans), the peripheral luminance correction coefficient (KbjBLHo) is obtained as shown in FIG. In other words, the peripheral luminance correction coefficient (KbjBLHo) is determined based on the full-screen steady-light photometric value (BVans) based on the full-screen steady-light photometric value (BVans) when the shooting scene is clear, cloudy, indoor, or night view. This is a coefficient for under-correction when it is determined that the sky is clear, and becomes zero when the shooting scene approaches a night view even if the face is in the normal light. For this reason, the main light emission amount correction unit 53 cancels the under correction in the night scene, and performs the under correction when the shooting scene is synchronized during the day and the face state is half-backlight and normal light.

  Then, the main light emission amount correction amount is obtained from the product of the main light emission correction value (ObjBLHo) and the peripheral luminance correction coefficient (KbjBLHo). The main light emission amount correction unit 53 obtains a final main light emission amount by correcting the main light emission amount subjected to the aperture correction using the main light emission amount correction amount, and executes the main light emission based on the obtained main light emission amount. The flash controller 39 is controlled. Then, the flash control unit 39 causes the flash light emitting unit 40 to perform main light emission with the corrected main light emission amount at time t9 (S-18). This flash main light emission is executed in synchronization with the photographing operation (S-19).

  In the photographing operation, the mirror driving mechanism 24 is controlled so as to perform a flip-up operation for moving the main mirror 13 to the mirror-up position for a moment, and during this time, the shutter 20 is driven based on the determined shutter speed (front curtain). Opening and closing of the rear curtain). While the shutter 20 is opened and closed, the imaging unit 21 captures a subject image. The image data acquired by the imaging unit 21 is accumulated in the imaging buffer memory 28 via the imaging A / D 27, and the image data read from the buffer memory 28 is sent to the image processing unit 29, where various kinds of data are obtained. After the image processing, the recording unit 30 records the image data for recording (S-20). Hereinafter, the above-described operation is repeated until the power switch is turned off (S-21).

  In the above embodiment, the main light emission amount of the flash is changed by adjusting the light amount, the light emission time, or both, but in the case of a zoom flash in which the flash light irradiation range is changed, the irradiation range is changed. The amount of light may be changed by zooming up to narrow or zooming down to widen.

  In each of the embodiments described above, the face detection unit 36 detects a face image area based on the luminance signal. However, the present invention is not limited to this, and based on the luminance signal and color difference signal converted from the RGB signal. The face image area may be detected by detecting the skin color area.

  In each of the above embodiments, the color filter provided in the photometric sensor 45 is an additive color mixed three primary color RGB color filter, but a primary color mixed CMY color filter may be provided instead. Further, an infrared cut filter that senses only light in the visible light range may be provided before the color filter.

  In each of the above embodiments, the built-in flash has been described. Needless to say, in the present invention, even when an external flash is used, the same procedure as described with reference to FIGS. The external flash is provided with a flash light emitting unit 40 and a flash control unit 39, and the flash control unit 39 is electrically connected to the control unit 41 on the electronic camera side through the terminal of the accessory shoe. When an external flash is used, the built-in flash is prohibited. As a difference in control on the electronic camera side, in the case of external flash photography, preliminary light emission is initially performed with a weak light emission amount, and the determination unit 51 compares the photometric value B with a predetermined threshold value I to obtain a photometric value B. When it is determined that it is less than the threshold value I, that is, when it is determined that the flash light is too weak to reach the subject, the second time is that the preliminary light emission is performed by increasing the light emission amount.

  In each of the above embodiments, the imaging unit 21 has been described as a single-plate type imaging sensor, but may be a three-plate type imaging unit having three imaging sensors. The photometric unit 32 may also be a three-plate type photometric unit having three photometric sensors.

  In each of the above embodiments, a case where one face image area is detected in the screen has been described. However, when a plurality of face image areas are detected in the screen, the face detection unit 36 is located at the center of the screen. A face image region that is positioned or a face image region having the largest face detection frame (face size) is selected as a main subject region, and a photometric value may be acquired from one main subject region selected by the photometric value calculation unit 38. Of course, when a plurality of face image areas are detected near the center of the screen, or when a plurality of largest face detection frames (face sizes) are detected, the face detection unit 36 selects the plurality of face image areas. The photometric value calculation unit 38 may select the main subject area and acquire the photometric value obtained by averaging the photometric values of the face image areas as the photometric value of the main face image area.

  In each of the above embodiments, the face detection unit 36 is provided. However, the present invention is not limited to this, and a person detection unit is provided instead of the face detection unit 36 so that the person detection unit detects a person as a main subject. It may be configured. In this case, the photometric value calculation unit 38 may acquire the photometric value based on the detected person image area. Of course, instead of the person detection unit, an animal detection unit may be provided so that the detected animal image region is detected as a main subject, and the photometric value calculation unit 38 acquires the photometric value based on the detected animal image region. Good.

  In each of the above embodiments, the calculation unit 50 calculates the total screen reflected light amount photometric value (photometric value A) by split photometry at the time of preliminary light metering and at the time of steady light photometry, but the average that averages the photometric values of all pixels. The photometric value A may be obtained by photometry.

  In each of the above-described embodiments, the main flash emission amount is calculated based on the photometric value A and the photometric value B. However, the present invention is not limited to this, and subject distance information from the photographing lens or focus detection unit is not limited thereto. In consideration of the above, the main light emission amount may be calculated.

  According to the present embodiment, the main subject area is overexposed with respect to the peripheral area by comparing the photometric value of the steady light in the main subject area with the exposure value set when actually shooting. If it is judged, the main flash will not be changed and the exposure will be under-corrected to reduce the exposure of the flash. Can be close to proper exposure.

DESCRIPTION OF SYMBOLS 10 Single-lens reflex electronic camera 11 Shooting lens 13 Main mirror 15 Focus plate 45 Photometric sensor 36 Face detection part 38 Photometric value calculation part

Claims (9)

In an imaging device that performs preliminary light emission before the main light emission during flash photography,
A photometric means for measuring the reflected light of the subject and outputting a photometric signal;
Main subject detection means for detecting a main subject region based on the photometric signal;
With it is that photometric signal obtained from the photometric means to the preliminary light emission prior to or after the a photometric value main object detecting means metering the main subject area detected, the exposure value set when performing shooting When the main subject area is determined to have a high exposure with respect to the peripheral area, the main light emission amount correcting means for reducing the light emission amount during the main light emission and under-correcting the exposure,
An imaging apparatus comprising: The imaging device according to claim 1,
With is that photometric signal obtained from the photometric means during the preliminary light emission, a first photometric value obtained by removing the component of the ambient light from the photometric value of the main subject region where the main subject detection means detects photometric value of the photometric areas a photometric value obtaining means for obtaining a second photometric value obtained by removing the stationary light component from each,
A main light emission amount calculating means for calculating a light emission amount during the main light emission based on the first photometric value and the second photometric value;
An imaging apparatus comprising: The imaging device according to claim 1 or 2,
The main light emission amount correcting means is a face area exposure deviation obtained by subtracting the exposure value from a photometric value obtained by measuring a main subject area using a photometric signal obtained from the photometric means before or after the preliminary light emission. An image pickup apparatus characterized in that the light emission amount during the main light emission is decreased in accordance with a change in value from minus to plus. The imaging device according to claim 3.
The main light emission amount correcting means is a full-screen stationary light metering of a photometry area using a main light emission correction amount determined according to the face area exposure deviation value and a photometric signal obtained from the photometry means before or after the preliminary light emission. An image pickup apparatus, wherein a correction amount for correcting the light emission amount during the main light emission is calculated from a product of a peripheral luminance correction coefficient determined according to a light photometric value. In the imaging device according to any one of claims 1 to 4,
A recording image pickup means for picking up an image of a subject imaged on an image pickup surface by a photographic lens for recording;
The imaging device, wherein the photometric means is a photometric imaging means for imaging a subject image formed on a plane conjugate with the imaging surface at a position different from the imaging means. The imaging device according to claim 2,
The photometric value obtaining means, the photometry from said main subject area preflash photometric value is photometric value obtained by photometry of the main subject region by using a photometric signal obtained from the photometric means during the preliminary light emission, before said preflash or after An imaging apparatus , wherein the first photometric value is calculated by subtracting a main subject area stationary light metering value, which is a photometric value obtained by metering a main subject area using a photometric signal obtained from the means . The imaging device according to claim 2,
The main light emission amount calculating unit weights the first photometric value as the size of the main subject region used when the photometric value acquiring unit acquires the first photometric value increases with respect to the entire screen. An imaging apparatus, wherein the main light emission amount is calculated by raising the photometric value. An imaging method for performing a preliminary light emission prior to main light emission during flash photography,
A photometric step of measuring the reflected light of the subject and outputting a photometric signal;
A main subject detection step for detecting a main subject region based on the photometric signal;
With is that photometric signal obtained from the photometric step before or after the preliminary light emission, the a main subject detection photometric value metering the main subject region detected in step, exposure value set when performing shooting DOO compares, when the main subject region is exposed to the peripheral region is determined to be high, and the light emission amount correction step for under-correcting the exposure by decreasing the light emission amount at the time of the main light emission,
An imaging method comprising: The imaging method according to claim 8,
With is that photometric signal obtained from the light measurement step during the preliminary light emission, a first photometric value obtained by removing the component of the ambient light from the photometric value of the main object area detected by the main subject detection step, the photometric value of the photometric areas A photometric value acquisition step of acquiring a second photometric value obtained by removing the stationary light component from
A main light emission amount calculating step of calculating a light emission amount during the main light emission based on the first photometric value and the second photometric value;
An imaging method comprising:

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