JP6388391B2 - Backlight discrimination device, control method thereof, control program, and imaging device - Google Patents

Description

  The present invention relates to a backlight discrimination device, a control method therefor, a control program, and an imaging device, and more particularly to backlight scene discrimination and flash light emission control.

  In general, in an imaging apparatus such as a digital camera, it is determined whether or not a shooting scene is a backlight scene, and if it is a backlight scene, switching from natural light shooting to flash shooting is performed. When determining whether or not the scene is a backlight scene, the subject luminance for each area, which is the output of the photometric sensor obtained by dividing the photometric area, is analyzed based on a predetermined algorithm. Then, it is determined whether or not the photographic scene is a backlight scene depending on whether or not the analysis result satisfies a predetermined threshold condition.

  For example, an average luminance value is obtained according to the output of a photometric sensor in which the photometric area is divided, and a luminance value in a focus detection area (hereinafter referred to as a focal luminance value) is obtained. Here, it is determined whether or not the scene is a backlight scene according to the difference between the average brightness value and the focus brightness value and the slope of brightness between the top side and the ground side of the screen (see Patent Document 1).

  Furthermore, there is a type in which a spectral image for each wavelength band that has passed through a spectral filter and spectral characteristic data indicating the characteristics of each spectral image are stored in a buffer memory, and a scene is determined according to the spectral characteristic data ( Patent Document 2).

JP 2004-109605 A JP 2009-71676 A

  By the way, as described in Patent Document 1, when a backlight scene is determined according to a photometric value (for example, a luminance value) that is an output of a photometric sensor in which a photometric area is divided, backlighting is caused by a difference in reflectance of a subject. The accuracy of scene determination may be reduced.

  In general, a photometric sensor that measures reflected light from a subject is adjusted so that an optimum photometric output is obtained when the reflectance of the subject is about 18%. The skin of a person varies depending on race and individual, but the reflectance is generally close to 18% in many cases. For this reason, when photographing a person, the accuracy of backlight scene determination is often maintained.

  On the other hand, when measuring green such as leaves of trees and plants that are highly likely to be subjects when taking pictures outdoors, the photometric value is lowered by one or two steps for a subject with a reflectance of 18%. There are many. For example, these subjects have a reflectance of about 10% to 5%.

  Even if such a tree or a leaf of a plant is a subject, if a backlight scene determination is performed in the same manner as a subject with a reflectance of 18%, the backlight scene determination cannot be performed with high accuracy. As a result, flash light emission is performed in a shooting scene where the flash light should not be emitted, which not only wastes energy but also may not provide a preferable image.

  In Patent Document 2, not only luminance information related to a subject but also color information of the subject is obtained, and the type and material of the subject are discriminated according to the information, and the issuance conditions are changed according to the discrimination result. It describes that flash emission is performed.

  However, Patent Document 2 does not describe how to change the light emission condition according to the type of the subject, and Patent Document 2 does not perform flash light emission by accurately determining a backlight scene. Have difficulty.

  Accordingly, an object of the present invention is to provide a backlight discrimination device capable of accurately determining a backlight scene and performing flash emission, a control method thereof, a control program, and an imaging device.

In order to achieve the above object, a backlight discrimination device according to the present invention is a backlight discrimination device for discriminating whether or not a shooting scene is a backlight scene, receives an image obtained in the shooting scene, and receives the image. Is divided into a plurality of photometric areas, and photometric means for obtaining luminance information and color information by measuring the luminance and color in each of the photometric areas, and a luminance indicating a difference in luminance in the image according to the luminance information and luminance difference calculation means for calculating a difference, said whether the detected second specific color different from the first specific color you and the first specific color predetermined in the metering area in accordance with the color information The second specific color when performing a backlight scene determination process for determining whether or not the shooting scene is a backlight scene according to the specific color determining means for determining whether or not the photographing scene is a backlight scene according to the luminance difference and the backlight determination threshold Region detected It is when we do not have, and having a a backlight determining means for performing the backlit scene determining process by changing the backlight determination threshold according to the number of the first metering area is a specific color.

  An imaging apparatus according to the present invention includes the backlight discrimination device described above, an imaging unit that captures an image of a subject and obtains an image, and a light emission control unit that controls the flash when the backlight determination unit determines that the scene is a backlight scene. It is characterized by having.

A control method according to the present invention is a control method for a backlight discrimination device that discriminates whether or not a photographic scene is a backlight scene. A photometric step of dividing and measuring the luminance and color in each of the photometric areas to obtain luminance information and color information, and a luminance difference calculation for obtaining a luminance difference indicating a luminance difference in the image according to the luminance information steps and the specific color determination determines whether the detected second specific color different from the first specific color you and the first specific color predetermined in the photometric area in accordance with the color information a step, wherein when said photographing scene in response to the brightness difference and the backlight determination threshold performs determining a backlit scene determination processing whether a backlit scene, the second region is a particular color is detected If have, and having a a backlight determination step of performing the backlit scene determining process by changing the backlight determination threshold according to the number of the first metering area is a specific color.

A control program according to the present invention is a control program used in a backlight discrimination device that determines whether or not a shooting scene is a backlight scene, and an image obtained in the shooting scene is stored in a computer included in the backlight discrimination device. Receiving the image, dividing the image into a plurality of photometric areas, and measuring the luminance and color in each of the photometric areas to obtain luminance information and color information; and luminance in the image according to the luminance information a luminance difference calculation step of calculating a luminance difference indicating a difference between the second specific color different from the first specific color you and the first specific color predetermined in the metering area in accordance with the color information A specific color determination step for determining whether or not the backlight is detected; and a backlight scene for determining whether or not the shooting scene is a backlight scene according to the luminance difference and the backlight determination threshold value. When performing the down determination process, when said second region is a specific color is not detected, the backlit scene by changing the backlight determination threshold according to the number of the first metering area is a specific color And a backlight determination step for performing a determination process.

  According to the present invention, when performing the backlight scene determination process for determining whether or not the shooting scene is a backlight scene according to the luminance difference and the backlight determination threshold, the photometry area that is the first specific color such as green is selected. The backlight scene determination process is performed by changing the backlight determination threshold according to the number. Accordingly, it is possible to accurately determine the backlight scene and perform flash emission.

It is sectional drawing which shows the structure about an example of an imaging device provided with the backlight discrimination device by the 1st Embodiment of this invention. It is a figure which shows the structure about an example of the sensor for focus detection shown in FIG. FIGS. 2A and 2B are diagrams for explaining the configuration of an example of the photometric sensor shown in FIG. 1, in which FIG. 1A shows a photometric area obtained by dividing the light receiving surface of the photometric sensor into a plurality of areas, and FIG. It is a figure which shows an example of the color filter arrange | positioned at each of these. It is a figure which shows an example of a response | compatibility with the visual field of a sensor for photometry, and the focus detection area | region of a sensor for focus detection in the finder visual field of the finder optical system shown in FIG. It is a block diagram for demonstrating an example of the control system in the camera shown in FIG. 6 is a flowchart for explaining an example of photographing processing in the camera shown in FIG. 5. 7 is a flowchart for explaining the exposure calculation process and the flash use determination process shown in FIG. 6 (part 1). 7 is a flowchart for explaining the exposure calculation process and the flash use determination process shown in FIG. 6 (part 2). It is a figure which shows an example of the backlight determination threshold value conditions set by the camera control part shown in FIG. It is a flowchart for demonstrating an example of the exposure calculation performed by the camera provided with the backlight discrimination device by the 2nd Embodiment of this invention, and flash use determination processing. It is a figure which shows an example of the backlight determination threshold value conditions set with the camera which concerns on the 2nd Embodiment of this invention.

  Hereinafter, an example of a backlight discrimination device according to an embodiment of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a cross-sectional view illustrating the configuration of an example of an imaging apparatus including a backlight discrimination device according to the first embodiment of the present invention.

  The illustrated imaging device is, for example, a single-lens reflex camera (hereinafter simply referred to as a camera) with interchangeable lenses, a camera body 1, an interchangeable lens unit (hereinafter simply referred to as an interchangeable lens) 2, and a light emitting device (hereinafter referred to as a flash device). 3).

  The camera body 1 is provided with an image sensor 12. The image sensor 12 is an area storage type image sensor such as a CMOS or CCD. An optical low-pass filter 11 is disposed on the front side of the image sensor 12, and a mechanical shutter 10 is disposed in front of the optical low-pass filter 11.

  A semi-transmissive main mirror 13 is disposed in front of the mechanical shutter 10. A first reflection mirror 14 is disposed between the mechanical shutter 10 and the main mirror 13. The main mirror and the first reflecting mirror 14 jump upward in the figure when photographing. In other words, the main mirror and the first reflection mirror 14 are retracted from the optical axis during shooting.

  A paraxial imaging plane 15 is defined on the optical axis of the light reflected by the first reflection mirror 14, and this paraxial imaging plane 15 forms an image of the imaging device 12 with respect to the first reflection mirror 14. It is in a position conjugate with the surface.

  The second reflecting mirror 16 reflects the light reflected by the first reflecting mirror 14 and guides it to a focus detection sensor (AF sensor) 20. Between the second reflection mirror 16 and the focus detection sensor 20, an infrared cut filter 17, a diaphragm 18, and a secondary imaging lens 19 are arranged.

  The aperture 18 is formed with two openings. The focus detection sensor 20 includes an area storage photoelectric conversion element such as a CMOS or a CCD.

  FIG. 2 is a diagram showing the configuration of an example of the focus detection sensor 20 shown in FIG.

  The focus detection sensor 20 has light receiving sensor portions 20A and 20B corresponding to the two openings of the diaphragm 18 shown in FIG. The light receiving sensor portions 20A and 20B are each divided into a large number of pixels.

  Further, although not shown, the focus detection sensor 20 includes peripheral circuits for signal accumulation and signal processing, and these peripheral circuits are integrated on the same chip together with the light receiving sensor portions 20A and 20B.

  Note that the configuration of the first reflection mirror 14, the second reflection mirror 16, the infrared cut filter 17, the diaphragm 18, the secondary imaging lens 19, and the focus detection sensor 20 is disclosed in Japanese Patent Laid-Open No. 9-184965. As described in the above, focus detection by a so-called image shift method can be performed at an arbitrary position on the photographing screen.

  A diffusive focus plate 21 is disposed above the main mirror 13, and a pentaprism 22 is disposed above the focus plate 21. Then, the light that has passed through the prism 22 enters the eyepiece lens 23.

  A third reflecting mirror 24 is disposed in the vicinity of the prism 22, and the light reflected by the third reflecting mirror 24 is guided to a photometric sensor 26 through a condenser lens 25. The photometric sensor 26 is for obtaining luminance information indicating the luminance of the subject and color information indicating the color. The photometric sensor 26 includes an area storage type photoelectric conversion element such as a CMOS or a CCD.

  FIG. 3 is a diagram for explaining the configuration of an example of the photometric sensor 26 shown in FIG. FIG. 3A is a diagram showing a photometry area obtained by dividing the light receiving surface of the photometry sensor 26 into a plurality of areas, and FIG. 3B shows an example of a color filter arranged in each of the photometry areas. FIG.

  In FIG. 3A, the light-receiving surface of the photometric sensor 20 is divided into a plurality of areas to define a plurality of photometric areas. The photometric sensor 20 outputs luminance information and color information related to the subject for each photometric area. In the illustrated example, the light receiving surface is divided into 35 areas of 5 rows × 7 columns, and photometric areas PD1 to PD35 are formed.

  As shown in FIG. 3B, each of the photometric areas PD1 to PD35 has a plurality of light receiving unit pixels, and a color filter having a predetermined arrangement is arranged in each of the photometric areas PD1 to PD35. ing.

  In the illustrated example, primary color filters 261 in which three spectral colors of B (blue), G (green), and R (red) are arranged in a Bayer array are arranged in each of the photometric regions PD1 to PD35.

  The photometric sensor 26 has signal amplification and signal processing peripheral circuits integrated on the same chip in addition to the light receiving unit pixels.

  Referring again to FIG. 1, a finder optical system is formed by the focus plate 21, the pentaprism 22, and the eyepiece lens 23. A part of the light metering sensor (AE sensor) 26 that is reflected by the main mirror 13 and further diffused by the focus plate 21 is incident outside the optical axis.

  FIG. 4 is a diagram illustrating an example of correspondence between the visual field of the photometric sensor 26 and the focus detection area of the focus detection sensor 20 in the finder visual field of the finder optical system illustrated in FIG.

  The field of view of the finder is indicated by reference numeral 71, and the field of view of the photometric sensor 26 is indicated by reference numeral 72. Here, a total of 11 regions of F10 to F12, F16 to F20, and F24 to F26 are shown as focus detection regions.

  These focus detection areas F10 to F12, F16 to F20, and F24 to F26 are arranged at positions corresponding to the photometry areas PD10 to PD12, PD16 to PD20, and PD24 to PD26, respectively.

  The camera body 1 is provided with a mount portion 27 for attaching an interchangeable lens (also referred to as a photographing lens) 2. The mount portion 27 is formed with a contact portion 28 for communicating with the photographic lens 2. Further, a connection portion 29 for attaching the flash device 3 is provided on the upper surface of the camera body 1.

  The interchangeable lens 2 includes optical lenses 30 a to 30 e and a diaphragm 31. Further, a contact portion 32 for communicating with the camera body 1 is provided on the rear end surface of the interchangeable lens 2, and a mount portion 33 for attaching the interchangeable lens 2 to the camera body 1 is provided.

  The flash device 3 includes a xenon tube 34 that is a light emitting unit, and the xenon tube 34 is disposed, for example, at a focal position of a reflection shade 35. A condensing Fresnel lens 36 is disposed on the front side of the xenon tube 34.

  The flash device 3 includes a monitor sensor (also referred to as a light emission monitor unit) 37 for monitoring the light emission amount of the xenon tube 34. The flash device 3 is formed with an attachment portion 38 for attaching the flash device 3 to the camera body 1. The light emitting unit of the flash device 3 may be an LED instead of a xenon tube.

  FIG. 5 is a block diagram for explaining an example of a control system in the camera shown in FIG. In FIG. 5, the same components as those shown in FIG. 1 are denoted by the same reference numerals.

  The camera body 1 is provided with a camera control unit 41. The camera control unit 41 is, for example, a one-chip microcomputer that includes an arithmetic unit (ALU), ROM, RAM, A / D converter, timer (Timer), and serial communication port (SPI). The camera control unit 41 controls the entire camera.

  The timing generator (TG) 42 generates a timing signal for controlling charge accumulation and charge reading in the photometric sensor (AE sensor) 26 under the control of the camera control unit 41. Output signals from the focus detection sensor (AF sensor) 20 and the photometry sensor (AE sensor) 26 are input to an input terminal of an A / D converter provided in the camera control unit 41.

  The signal processing circuit 43 drives and controls the image sensor 12 under the control of the camera control unit 41 to A / D convert an image signal (imaging signal) that is an output of the image sensor 12, and then performs predetermined signal processing. Let it be image data. Furthermore, the signal processing circuit 43 performs predetermined image processing such as compression processing when recording image data.

  The memory 44 is, for example, a DRAM and is used as a work memory at the time of signal processing by the signal processing circuit 43. Further, the memory 44 is used as a VRAM for displaying an image on the display unit 45.

  The display unit 45 is constituted by, for example, a liquid crystal panel, and various types of shooting information and images obtained as a result of imaging are displayed on the display unit 45. The camera control 41 controls the lighting of the display unit 45. The storage unit 46 includes, for example, a flash memory or an optical disk, and the signal processing circuit 43 stores image data in the storage unit 46.

  As shown in the figure, a first motor driver 47, a release switch (SW) 49, and a shutter drive unit 50 are connected to the camera control unit 41. The first motor driver 47 drives the first motor 48 for up / down the main mirror 13 and the first reflecting mirror 14 and charging the mechanical shutter 10 under the control of the camera control unit 41. To do.

  The release SW 49 is a switch for instructing the camera control unit 41 to start photographing. The shutter drive unit 50 drives the mechanical shutter 10 under the control of the camera control unit 41.

  The contact portion 28 provided in the camera body 1 is connected to the SPI provided in the camera control unit 41. Further, the connection unit 29 provided in the camera body 1 is connected to an SPI provided in the camera control unit 41.

  The interchangeable lens 2 is provided with a lens control unit 51. The lens control unit 51 is, for example, a one-chip microcomputer incorporating an ALU, ROM, RAM, timer, and SPI. The second motor driver 52 drives a second motor 53 for performing focus adjustment under the control of the lens control unit 51. The third motor driver 54 drives a third motor 55 for driving the diaphragm 31 under the control of the lens control unit 51.

  A distance encoder 56 and a zoom encoder 57 are connected to the lens control unit 51. The distance encoder 56 obtains subject distance information indicating the extension amount of the focus adjustment lens (that is, the focus lens), that is, the subject distance. The zoom encoder 57 obtains focal length information indicating the focal length at the time of shooting according to the movement of the zoom lens provided in the interchangeable lens 2. The contact part 32 is connected to an SPI provided in the lens control part 51.

  When the interchangeable lens 2 is attached to the camera body 1, the contact portions 28 and 32 are connected. Thereby, the lens control unit 51 can perform data communication with the camera control unit 41. Then, the lens control unit 51 sends the lens-specific optical information, subject distance information, and focal length information necessary for performing focus detection (that is, distance measurement) and exposure calculation (that is, photometry) to the camera control unit 41. send.

  The camera control 41 sends focus adjustment information and aperture information obtained by focus detection and exposure calculation to the lens control unit 51. The lens control unit 51 controls the second motor driver 52 according to the focus adjustment information and also controls the third motor driver 54 according to the aperture information.

  The flash device 3 includes a flash control unit 61. Although not shown, the flash control unit 61 is, for example, a one-chip microcomputer incorporating an ALU, ROM, RAM, A / D converter, timer, and SPI. The boosting unit 62 generates a high voltage of about 300 V necessary for light emission of the xenon tube that is the light emitting unit 34, and performs charging with the high voltage.

  When the flash device 3 is attached to the camera body 1, the connection units 38 and 29 are connected, and the flash control unit 61 can perform data communication with the camera control unit 41. The flash controller 61 controls the booster 62 under the control of the camera controller 41 to start and stop the emission of the xenon tube 34. Further, the flash control unit 61 sends the detection result by the monitor sensor 37 to the camera control 41.

  FIG. 6 is a flowchart for explaining an example of photographing processing in the camera shown in FIG. Note that the processing according to the illustrated flowchart is performed under the control of the camera control unit 41.

  Now, when a power switch (not shown) provided in the camera is turned on, the camera control unit 41 becomes operable. Then, the camera control unit 41 obtains lens information necessary for distance measurement and photometry from the lens control unit 51 (step S101: lens communication).

  Subsequently, the camera control unit 41 controls the focus detection sensor 20 by the TG 42 to perform charge accumulation (signal accumulation), and when the signal accumulation is completed, reads a signal (that is, charge) accumulated in the focus detection sensor 20. (Step S102). The camera control unit 41 performs A / D conversion on the signal charge to obtain focus detection data, and performs data correction such as shading correction on the focus detection data.

  Next, the camera control unit 41 performs focus detection for each focus detection area in accordance with the lens information and focus detection data, and obtains a focus detection result (step S103). And the camera control part 41 determines the focus detection area which should be focused among focus detection areas F10-F12, F16-F20, and F24-F26 shown in FIG.

  In determining the focus detection area, for example, the camera control unit 41 determines the focus detection area designated by the user as the focus detection area to be focused. The camera control unit 41 may determine the main subject area as a focus detection area to be focused.

  The camera control unit 41 calculates a lens movement amount for achieving a focus state according to a focus detection result in a focus detection region to be focused. Then, the camera control unit 41 sends the lens driving amount to the lens control unit 51. The lens control unit 51 controls the second motor driver 52 based on the lens driving amount and drives the focus adjustment lens by the second motor 53 (step S103). As a result, the interchangeable lens 2 is brought into focus with respect to the main subject.

  At this time, since the subject distance information is changed by driving the focus adjustment lens, the lens control unit 51 updates the lens information.

  Subsequently, the camera control unit 41 controls the TG 42 to perform accumulation control and signal readout control for the photometric sensor 26 (step S104). As a result, the photometric sensor 26 accumulates charges for a predetermined time and outputs signal charges. The camera control unit 41 A / D converts the signal charge and stores it in the RAM as photometric data.

  Next, the camera control unit 41 performs predetermined exposure calculation processing and determination processing for determining whether or not flash photography is performed based on the photometry data stored in the RAM as described later (step S105). ).

  In accordance with the processing in step S105, the camera control unit 41 determines whether to perform flash photography, that is, whether to use the flash (step S106). If it is determined that the flash is to be used (YES in step S106), the camera control unit 41 controls the flash control unit 61 to operate the boosting unit 62 to charge a high voltage sufficient for flash emission (step S107: Flash charge).

  Next, the camera control unit 41 confirms whether or not the release SW 49 has been turned on (step S108). If release SW 49 is not turned on (NO in step S108), camera control unit 41 returns to the process in step S101.

  When the release SW 49 is turned on (YES in step S108), the camera control unit 41 checks whether or not it is determined to perform flash photography in step S105 described above (step S109). If it is determined that flash photography is to be performed (YES in step S109), the camera control unit 41 instructs the flash control unit 61 to perform flash preliminary light emission (step S110).

  As a result, the flash controller 61 causes the xenon tube 34 to emit light (preliminary light emission). The flash control unit 61 monitors the output signal from the monitor sensor 37 and controls the light emission of the xenon tube 34 so that the light emission amount of the xenon tube 34 becomes a preset preliminary light emission amount.

  When the preliminary light emission is performed, the camera control unit 41 controls the TG 42 to perform predetermined charge accumulation control and signal readout control for the photometric sensor 26. As a result, the photometric sensor 26 accumulates charges for a predetermined time and outputs a signal charge. Then, the camera control unit 41 performs A / D conversion on the signal charge, and performs a main light emission amount calculation for determining the flash main light emission amount by a known method in accordance with the light emission photometric data (step S110).

  Subsequently, the camera control unit 41 drives the first motor 48 by the first motor driver 47 to jump up (retract from the optical axis) the main mirror 13 and the first reflection mirror 14. Then, the camera control unit 41 sends to the lens control unit 51 aperture control information indicating the opening of the aperture 31 obtained by the exposure calculation process described above.

  The lens control unit 51 drives and controls the third motor 55 by the third motor driver 54 based on the diaphragm control information to drive the diaphragm 31 (step S111). As a result, the interchangeable lens (photographing lens) 2 is in a narrowed state.

  If it is determined not to perform flash photography (NO in step S109), the camera control unit 41 proceeds to the process of step S111.

  Subsequently, the camera control unit 41 causes the shutter driving unit 50 to open the shutter 10 (step S112). As a result, a light beam (optical image) enters the imaging element 12 from the photographing lens 2 and imaging is performed (step S112).

  Here, the camera control unit 41 sets the charge accumulation time and the readout gain according to the shutter control time and the imaging sensitivity obtained by the exposure calculation process described above, and the signal processing circuit 43 controls the charge accumulation of the image sensor 12. And signal readout control is performed.

  When performing flash photography, the camera control unit 41 sends a flash emission instruction to the flash control unit 61 in synchronization with the imaging timing. The flash control unit 61 causes the xenon tube 34 to emit light according to the flash emission instruction and monitors the output signal of the monitor sensor 37 so that the light emission amount of the xenon tube 34 becomes the main light emission amount obtained in step S110. The light emission of the xenon tube 34 is controlled. Thereby, imaging by flash emission is performed.

  When the imaging is completed, the camera control unit 41 causes the shutter driving unit 50 to put the shutter 10 in a light shielding state (step S113). Thereby, the optical image incident on the image sensor 12 is blocked.

  Further, the camera control unit 41 instructs the lens control unit 51 to open the aperture 31. As a result, the lens control unit 51 drives and controls the third motor 55 by the third motor driver 54 to open the diaphragm 31 (step S113). Further, the camera control unit 41 drives and controls the first motor 48 by the first motor driver 47, and lowers the main mirror 13 and the first reflection mirror 14 (step S113).

  Subsequently, the camera control unit 41 performs A / D conversion on the image signal output from the image sensor 12 by the signal processing circuit 43, and then performs predetermined correction processing and interpolation processing (step S114). Further, the camera control unit 41 performs white balance processing by the signal processing circuit 43 (step S115).

  For example, the signal processing circuit 43 divides the image into a plurality of areas, and extracts a white area of the subject according to the color difference signal for each area. Then, the signal processing circuit 43 performs white balance processing by performing gain correction on the red channel and the blue channel in the entire image based on the white region.

  The camera control unit 41 compresses and converts the image data after the white balance processing into a recording file format by the signal processing circuit 43, and then stores it in the storage unit 46. Then, the camera control unit 41 ends the shooting process.

  7A and 7B are flowcharts for explaining the exposure calculation process and the flash use determination process shown in FIG.

  As described with reference to FIG. 6, the photometric data is stored in the RAM. The camera control unit 41 adds the B, G, and R components (spectral components) for each of the photometric areas (blocks) PD1 to PD35 to obtain integrated values B (i), G (i), and R (i). Obtained (step S151). Then, the camera control unit 41 performs matrix calculation on the integral values B (i), G (i), and R (i) by the following equation (1) using predetermined coefficients (M11 to M33). Do.

  Thus, the camera control unit 41 obtains subject luminance information Yr (i) and biaxial subject color information Cx (i) and Cy (i) for each of the photometric areas PD1 to PD35 (step S151).

  However, i = 1 to 35.

  In calculating the subject luminance information Yr (i), normally, M11 is about 0.2, M12 is about 0.5, and M13 is about 0.3. The spectral characteristics of the detected luminance 26 are made closer.

  As shown in the following formula (2), the camera control unit 41 performs a conversion function process on the subject luminance information Yr (i) for each of the photometric areas PD1 to PD35 into a logarithmic compression system with 2 as a base. Further, the camera control unit 41 obtains subject luminance information Y (i) in the logarithmic compression system by performing correction processing for correcting the luminance information S (i) for each photometric area based on the optical characteristics corresponding to the lens information. .

Y (i) = log ₂ {Yr (i)} × S (i) (2)
In general, since the shutter speed and the aperture value are set in logarithmic series of steps, the camera control unit 41 obtains subject luminance information Y (i) in the logarithmic compression system as described above. The coefficients M21 to M33 used when calculating the subject color information Cx (i) and Cy (i) are not limited to specific coefficients as long as the color information excluding the luminance component can be expressed in a biaxial space.

  Subsequently, the camera control unit 41 determines whether each of the photometric areas PD1 to PD35 is an area that can be regarded as a skin color area or a green area. Here, for example, when the subject color information Cx (i) and Cy (i) obtained for each of the photometry areas PD1 to PD35 satisfy the following expression (3), the camera control unit 41 sets the photometry area to the skin color. The area is detected (step S152).

Cxsmin ≦ Cx (i) ≦ Cxsmax
Cysmin ≦ Cy (i) ≦ Cysmax (3)
Cxsmin, Cxsmax, Cysmin, and Cysmax are threshold values, and are values that delimit a range that can be regarded as a skin color in the color space converted by the coefficients M21 to M33.

  Similarly, when the subject color information Cx (i) and Cy (i) obtained for each of the photometry areas PD1 to PD35 satisfy the following expression (4), the camera control unit 41 sets the photometry area as a green area. It detects (step S152).

Cxgmin ≦ Cx (i) ≦ Cxgmax
Cygmin ≦ Cy (i) ≦ Cygmax (4)
Cxgmin, Cxgmax, Cygmin, and Cygmax are threshold values, and are values that delimit a range that can be regarded as green in the color space converted by the coefficients M21 to M33. Usually, the skin color range and the green range are separated in the color space and do not overlap.

  Subsequently, the camera control unit 41 calculates the skin color reliability Ssc (i) related to the skin color area detection for each of the photometric areas PD1 to PD35. First, the camera control unit 41 sets fs (i) = 1 for a region regarded as a skin color region among the photometric regions PD1 to PD35, and sets fs (i) = 0 for other regions.

  Further, the camera control unit 41 obtains a luminance coefficient kys (i) to be set based on the subject luminance information Y (i) obtained for each of the photometric areas PD1 to PD35. Here, the camera control unit 41 sets the luminance coefficient kys (i) = 1 when the subject luminance information Y (i) in the photometric area is within a predetermined range. Then, as the subject luminance information Y (i) deviates from the predetermined range, the camera control unit 41 makes the luminance coefficient kys (i) smaller than 1.

  By the way, if the sensor surface illuminance in the photometric sensor 26 is too low, the S / N deteriorates and the detection accuracy deteriorates. If the sensor surface illuminance is too large, the detection accuracy deteriorates due to the influence of saturation or the like. For this reason, as described above, the luminance coefficient kys (i) is changed according to the subject luminance information Y (i).

  The camera control unit 41 sets the position coefficient ks (i) according to the arrangement of the photometry area. Here, the camera control unit 41 sets the position coefficient ks (i) = 1 for the photometric area close to the center of the image, and approaches the position coefficient ks (i) to 0 as the photometric area is closer to the peripheral part of the image. . That is, since the skin color area is regarded as a main subject area as a person, the skin color reliability is increased in the photometry area near the center of the image, and the skin color reliability is decreased in the photometry area near the periphery of the image.

  The camera control unit 41 obtains the skin color reliability Ssc (i) for each of the photometric areas PD1 to PD35 according to the following equation (5).

Ssc (i) = fs (i) × kys (i) × ks (i) (5)
Next, the camera control unit 41 calculates the green reliability Sgc (i) related to the green area detection for each of the photometric areas PD1 to PD35. First, the camera control unit 41 sets fg (i) = 1 for a photometric area regarded as a green area, and sets fg (i) = 0 for other areas.

  Further, the camera control unit 41 obtains a luminance coefficient kyg (i) to be set based on the subject luminance information Y (i) obtained for each of the photometric areas PD1 to PD35. Here, the camera control unit 41 sets the luminance coefficient kyg (i) = 1 when the subject luminance information Y (i) is in the luminance range set by measuring the leaves of trees or plants outdoors during the daytime. To do. Then, as the subject luminance information Y (i) is out of the luminance range, the camera control unit 41 makes the luminance coefficient kyg (i) smaller than 1.

  The camera control unit 41 obtains the green reliability Sgc (i) for each of the photometric areas PD1 to PD35 according to the following equation (6).

Sgc (i) = fg (i) × kyg (i) (6)
Subsequently, the camera control unit 41 obtains an average value of the subject luminance information Y (i) in the photometry area where the skin color reliability Ssc (i) is equal to or greater than a predetermined skin color threshold, and the average value is referred to as the skin color portion luminance value Ysc. (Step S153).

  Next, the camera control unit 41 confirms the positional relationship between the photometric area where the skin color reliability Ssc (i) is equal to or greater than the skin color threshold and the focused focus detection area (step S154). If the camera control unit 41 determines to change the focus detection area to be focused in the image according to the confirmation result, the camera control unit 41 performs focus adjustment again as described above.

  Subsequently, the camera control unit 41 obtains defocus amounts in a total of 11 regions of the focus detection regions F10 to F26 in a state where the focus adjustment is completed. This defocus amount is data indicating the amount of defocus. If the focus detection area is in focus with respect to the subject, the defocus amount is 0. As the defocus amount increases, the defocus amount is increased. growing.

  The camera control unit 41 obtains an average value of the subject luminance information Y (i) in the photometry area corresponding to the focus detection area whose defocus amount is smaller than a predetermined focus threshold, and uses the average value as the in-focus unit luminance value Yjp. (Step S156).

  Next, the camera control unit 41 increases the weighting coefficient for the center portion or the focus area of the image, and multiplies the subject luminance information value Y (i) of the photometry areas PD1 to PD35 by the weighting coefficient, and then averages the average value. And the average value is set as the average subject luminance value Yae (step S157).

  Next, the camera control unit 41 compares the average subject brightness value Yae with a preset set brightness value, and determines whether or not flash photography (low brightness automatic light emission) is performed (step S158). Here, the camera control unit 41 determines that flash photography is performed when the average subject brightness value Yae <the set brightness value (less than the set brightness value).

  If it is determined that flash photography is to be performed (YES in step S158), the camera control unit 41 determines the shutter speed, aperture value, and photography sensitivity suitable for flash photography based on the average subject luminance value Yae as an exposure factor (flash photography). Control value) (step S159). Then, the camera control unit 41 proceeds to the process of step S106 shown in FIG.

  On the other hand, when it is determined that flash photography is not performed (NO in step S158), the camera control unit 41 obtains luminance gradient information ΔYy in the vertical direction in the image based on the subject luminance information Y (i) for each photometric area ( Step S160). Here, it is assumed that the columns of the photometric areas PD1 to PD7 shown in FIG. 3A measure the top side of the image, and the columns of the photometric areas PD29 to PD35 measure the ground side of the image.

  First, the camera control unit 41 obtains luminance values Yy1 to Yy5 for each column by averaging the subject luminance information Y (i) for each photometric area for each column as shown in Expression (7).

Yy1 = ΣY (i) ÷ 7 where i = 1 to 7
Yy2 = ΣY (i) ÷ 7 where i = 8-14
Yy3 = ΣY (i) ÷ 7 where i = 15 to 21 (7)
Yy4 = ΣY (i) ÷ 7 where i = 22 to 28
Yy5 = ΣY (i) ÷ 7 where i = 29 to 35
When obtaining the luminance gradient information ΔYy in the vertical direction in the image, the gradient coefficient of the approximate straight line of the luminance values Yy1 to Yy5 for each column may be calculated. For simplicity, the luminance gradient information ΔYy in the vertical direction may be obtained as shown by the following equation (8).

ΔYy = ((Yy1 + Yy2) ÷ 2- (Yy4 + Yy5) ÷ 2) ÷ 3 (8)
The luminance inclination information ΔYy obtained as described above becomes a larger value as the celestial luminance value is higher and the terrestrial luminance value is lower in the subject luminance information Y (i) for each photometric area, and the degree of backlighting It becomes one parameter which shows.

  Next, the camera control unit 41 checks whether or not a skin color area is detected (step S161). Here, the camera control unit 41 checks whether or not a photometric area with fs (i) = 1 exists in the process of step S152.

  If the skin color area is detected (YES in step S161), the camera control unit 41 determines whether or not the sum ΣSsc (i) of the skin color reliability Ssc (i) for each photometry area is equal to or greater than a predetermined sum value. Check (step S162).

  If the total sum ΣSsc (i) is equal to or greater than a predetermined total value (YES in step S162), the camera control unit 41 is likely to have a main subject as a person. Then, the camera control unit 41 uses the skin color portion brightness value (specific color brightness value) Ysc as the main subject portion brightness value, and, as shown in Expression (9), the difference ΔYx between the skin color portion brightness value Ysc and the average subject brightness value Yae. Is obtained (step S163).

ΔYx = Yae−Ysc (9)
The difference ΔYx thus determined becomes a larger value as the skin color portion luminance value Ysc is lower than the average subject luminance value Yae, and becomes one parameter indicating the degree of backlighting. Next, the camera control unit 41 sets a backlight determination threshold condition used in the backlight scene determination process as follows (step S164).

  FIG. 8 is a diagram illustrating an example of a backlight determination threshold condition set by the camera control unit 41 illustrated in FIG.

  In FIG. 8, the horizontal axis indicates the difference ΔYx, and the vertical axis indicates the luminance gradient information ΔYy in the vertical direction. The backlight determination threshold condition indicates a threshold condition for determining whether or not shooting is performed with flash emission. Here, the difference ΔYx and the luminance gradient information ΔYy in the vertical direction are each indicated by the number of steps (logarithm of 2).

  Here, the camera control unit 41 determines to use the threshold Th-S indicated by the alternate long and short dash line in the backlight determination threshold condition. The camera control unit 41 determines that flash emission is performed when ΔYx> 1 and ΔYy ≧ 0 or when the condition of ΔYy> 1 is satisfied. In other cases, the camera control unit 41 determines not to perform flash emission.

  Note that the backlight determination threshold condition is determined in consideration of the fact that if a photograph is taken one step darker than the photographing exposure in which the skin color is considered to be appropriate, such as a person's face, the impression is too dark.

  If the skin color area is not detected (NO in step S161), the camera control unit 41 determines whether or not a predetermined number or more of green areas are detected (step S165). Here, the camera control unit 41 determines that a green region has been detected when the number of photometric regions where fg (i) = 1 is equal to or greater than a predetermined number.

  Note that if the total sum ΣSgc (i) of the green reliability Sgc (i) in each photometric area is equal to or greater than a predetermined value, the camera control unit 41 may determine that a green area has been detected. If the total sum ΣSsc (i) is less than the predetermined total value (NO in step S162), the camera control unit 41 proceeds to the process in step S165.

  When a predetermined number or more of green regions are detected (YES in step S165), the camera control unit 41 determines that there is a high possibility that the leaves of the trees are subjects. Then, the camera control unit 41 uses the in-focus portion luminance value Yjp as the main subject portion luminance value, and, as shown in Expression (10), the in-focus portion luminance value Yjp and the average subject luminance value (average luminance value) Yae A difference (luminance difference) ΔYx is obtained (step S166).

ΔYx = Yae−Yjp (10)
The difference ΔYx obtained in this way becomes a larger value as the in-focus portion luminance value Yjp is lower than the average subject luminance value Yae, and becomes one parameter indicating the degree of backlighting.

  Next, the camera control unit 41 determines to use the backlight determination threshold Th-G indicated by the solid line in FIG. 8 (step S167). In the range of ΔYx ≦ 1, the camera control unit 41 satisfies ΔYy> 1.25 or ΔYy> 0, and (ΔYx, ΔYy) = (1.0, 1.25) and (ΔYx, ΔYy) = ( 1.5, 0), it is determined that flash emission is performed when the condition in the upper right area of the oblique line connecting with the line is connected. In other cases, the camera control unit 41 determines not to perform flash emission.

  Green color such as leaves of trees has a lower reflectance than skin color, and the subject luminance value under the same illumination condition is often lower by one or more steps. Therefore, if the same backlight determination threshold is used as the backlight determination threshold when the skin color area is detected, a shooting scene that is not backlight is often erroneously determined to be a backlight scene. Therefore, erroneous determination is reduced by using the backlight determination threshold Th-G that is larger than the backlight determination threshold Th-S used when the skin color area is detected.

  If a predetermined number or more of the green regions are not detected (NO in step S165), the camera control unit 41 cannot identify the subject because it is not a person or a leaf of trees. Then, the camera control unit 41 calculates a difference ΔYx between the in-focus portion luminance value Yjp and the average subject luminance value Yae by using the in-focus portion luminance value Yjp as the main subject portion luminance (step S168).

  ΔYx obtained in this way becomes a larger value as the focused portion luminance value Yjp is lower than the average subject luminance value Yae, and becomes one parameter indicating the degree of backlighting.

  Next, the camera control unit 41 determines to use the backlight determination threshold Th-U indicated by a broken line in FIG. 8 (step S169). In the range of ΔYx ≦ 0.75, the camera control unit 41 satisfies ΔYy> 0.75 or ΔYy> 0, and (ΔYx, ΔYy) = (0.75, 0.75) and (ΔYx, ΔYy) =. If the condition of the upper right area of the oblique line connecting (1.25, 0) is satisfied, it is determined that flash emission is performed. In other cases, the camera control unit 41 determines not to perform flash emission.

  There are various scenes in which the skin color area is not detected and the green area is not detected and the subject cannot be specified. In such a scene, although a person is a small subject, the skin color region may not be detected. In such a case, the backlight determination threshold is set low here in order to avoid failure of photographing due to not performing flash emission.

  After the process of step S164, S167, or S169 described above, the camera control unit 41 determines whether to perform flash emission according to the backlight determination threshold (step S170). If it is determined that flash emission is to be performed (YES in step S170), the camera control unit 41 determines an exposure factor (flash shooting suitable for flash shooting, shutter speed, aperture value, and shooting sensitivity suitable for the average subject luminance value Yae). Control value) is determined (step S171). Then, the camera control unit 41 proceeds to the process of step S106 shown in FIG.

  On the other hand, if it is determined not to perform flash emission (NO in step S170), the camera control unit 41 uses a shutter speed and aperture suitable for natural light photography without performing flash emission based on the average subject luminance value Yae. The value, shooting sensitivity, etc. are determined as exposure factors (natural light shooting control values) (step S172). Then, the camera control unit 41 proceeds to the process of step S106 shown in FIG.

  As described above, in the first embodiment of the present invention, the backlight determination threshold used for backlight determination is changed according to the detection result of the skin color region and the green region. Therefore, the backlight scene is accurately determined, Unnecessary flash emission can be reduced.

[Second Embodiment]
Next, an example of a camera provided with the backlight discrimination device according to the second embodiment of the present invention will be described.

  The configuration of the camera according to the second embodiment is the same as that of the camera shown in FIGS. In the camera according to the second embodiment, the photographing process is performed as described with reference to FIG. At this time, in the second embodiment, the exposure calculation and the flash use determination process are different from those in the first embodiment.

  FIG. 9 is a flowchart for explaining an example of exposure calculation and flash use determination processing performed by a camera including a backlight discrimination device according to the second embodiment of the present invention.

  When the exposure calculation and the flash use determination process are started, the processes of steps S151 to S160 described with reference to FIG. 7A are performed. And step S161-S167 demonstrated in FIG. 7B is performed.

  In the process of step S165 shown in FIG. 7B, if a predetermined number or more of green regions are not detected (NO in step S165), the camera control unit 41 sets the backlight determination threshold condition as a default condition set in advance ( Step S261).

  FIG. 10 is a diagram illustrating an example of a backlight determination threshold condition set by the camera according to the second embodiment of the present invention.

  In FIG. 10, the horizontal axis indicates the difference ΔYx, and the vertical axis indicates the luminance gradient information ΔYy in the vertical direction. The backlight determination threshold condition shown in FIG. 10 indicates the threshold condition for determining whether or not to perform shooting with flash emission, similarly to the backlight determination threshold condition shown in FIG.

  Here, the camera control unit 41 sets a default condition as the backlight determination threshold condition. In the example shown in FIG. 10, the camera control unit 41 determines to use threshold values (Th-Ux, Th-Uy) indicated by broken lines as default conditions.

  Under this default condition, the camera control unit 41 determines that flash emission is performed when ΔYx> 0.75 and ΔYy ≧ 0 or when ΔYy> 0.75 is satisfied. In other cases, the camera control unit 41 determines not to perform flash emission.

  Since the default condition is used in a scene where the skin color area is not detected and the number of green areas is less than a predetermined number and the subject cannot be specified, the backlight determination threshold is set low.

  Further, in step S261, the camera control unit 41 calculates a difference ΔYx between the in-focus portion luminance value Yjp and the average subject luminance value Yae with the in-focus portion luminance value Yjp as the main subject portion luminance.

  Subsequently, the camera control unit 41 determines whether or not a predetermined number or more of green regions are detected again in the same manner as in the process of step S165 (step S262). When a predetermined number or more of green regions are detected (YES in step S262), the camera control unit 41 assumes that there is a high possibility that leaves of trees and the like are included as subjects. Then, the camera control unit 41 changes the backlight determination threshold condition (step S263). Here, the camera control unit 41 changes the threshold value Th-Uy among the default conditions to the threshold value Th-Gy indicated by a solid line, and sets it as the first changed default condition.

  Under the first change default condition, the camera control unit 41 determines to perform flash emission when ΔYx> 0.75 and ΔYy ≧ 0 or when ΔYy> 1.25 is satisfied. In other cases, the camera control unit 41 determines not to perform flash emission.

  In this way, by changing the default condition, when the luminance value of the subject is low, such as leaves of trees, the threshold value regarding the luminance gradient information ΔYy in the vertical direction is changed to an appropriate threshold value.

  Subsequently, the camera control unit 41 determines whether or not a predetermined number or more of skin color regions have been detected (step S264). Here, if the number of photometric areas in which fs (i) = 1 is equal to or greater than a predetermined number, the camera control unit 41 determines that skin color is detected. Note that if the sum ΣSsc (i) of the skin color reliability Ssc (i) in each photometric area is equal to or greater than a predetermined value, the camera control unit 41 may determine that there is skin color detection.

  If the predetermined number or more of the skin color regions are not detected (NO in step S264), the camera control unit 41 determines that there is a high possibility that the leaves of the trees are the subject. Then, the camera control unit 41 changes the backlight determination threshold condition (step S265). Here, the camera control unit 41 changes the threshold value Th-Ux among the default conditions to the threshold value Th-Gx indicated by a solid line, and sets the second changed default condition. Then, the camera control unit 41 proceeds to the process of step S170 illustrated in FIG. 7B.

  Under the second changed default condition, the camera control unit 41 determines that flash emission is performed when ΔYx> 1.25 and ΔYy ≧ 0 or when ΔYy> 0.75 is satisfied. In other cases, the camera control unit 41 determines not to perform flash emission.

  By changing the default condition in this way, the threshold for the difference ΔYx between the average subject luminance value Yae and the in-focus portion luminance value Yjp when the subject luminance value is low, such as leaves of trees, is changed to an appropriate threshold value. Is done.

  If the predetermined number or more of the green regions are not detected (NO in step S262), the camera control unit 41 determines whether or not the predetermined number or more of the skin color regions are detected in the same manner as the process of step S264. (Step S266).

  When a predetermined number or more of skin color regions are detected (YES in step S266), the camera control unit 41 determines that there is a high possibility that the person is the main subject. Then, the camera control unit 41 changes the backlight determination threshold condition (step S267). Here, the camera control unit 41 changes the threshold value Th-Ux among the default conditions to the threshold value Th-Sx indicated by the alternate long and short dash line, and sets the third changed default condition.

  Under the third change default condition, the camera control unit 41 determines that flash emission is performed when ΔYx> 1.0 and ΔYy ≧ 0 or when ΔYy> 0.75 is satisfied. In other cases, the camera control unit 41 determines not to perform flash emission.

  By changing the default condition in this way, the threshold for the difference ΔYx between the average subject luminance value Yae and the in-focus portion luminance value Yjp is changed to an appropriate threshold when a person becomes the main subject.

  Thereafter, the camera control unit 41 calculates the difference ΔYx between the skin color portion brightness value Ysc and the average subject brightness value Yae using the skin color portion brightness value Ysc as the main subject portion brightness (step S268). Then, the camera control unit 41 proceeds to the process of step S170 illustrated in FIG. 7B.

  Note that when a predetermined number or more of skin color regions are detected in step S264 (YES in step S264), the camera control unit 41 proceeds to the process of step S267. If the predetermined number or more of the skin color regions are not detected (NO in step S266), the camera control unit 41 proceeds to the process of step S170 shown in FIG. 7B.

  As described above, in the second embodiment of the present invention, the threshold range in the backlight determination threshold condition is changed according to the detection result of the green region and the skin color region. Therefore, the backlight scene is accurately determined. Unnecessary flash emission can be reduced.

  In the embodiment described above, the number of photometry areas in the photometry sensor and the number of focus detection areas in the focus detection sensor are examples. Further, although the embodiment has been described in which color detection is performed for each block in the photometric area, color detection may be performed in finer units such as for each Bayer. Moreover, the threshold value in the backlight determination threshold condition is an example. In the above embodiment, the photometric sensor is provided separately from the image sensor. You may make it perform photometry according to the output of an image pick-up element.

  As is clear from the above description, in the example shown in FIG. 5, the photometric sensor (AE sensor) 26, the TG 42, and the camera control unit 41 function as photometric means, and the camera control unit 41 is a luminance difference calculating means and specifying Functions as color determination means and backlight determination means.

  Further, the focus detection sensor (AF sensor) 20 and the camera control unit 41 function as focus detection means, and the camera control unit 41 and the flash device 3 function as light emission means.

  The camera control unit 41 functions as a luminance inclination calculation unit, and the interchangeable lens 2, the image sensor 12, and the signal processing circuit 43 function as an imaging unit. The camera control unit 41 and the flash control unit 61 function as a light emission control unit.

  In the illustrated example, at least the photometric sensor (AE sensor) 26, the TG 42, the camera control unit 41, and the focus detection sensor (AF sensor) 20 constitute a backlight discrimination device.

  As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to these embodiment, Various forms of the range which does not deviate from the summary of this invention are also contained in this invention. .

  For example, the function of the above embodiment may be used as a control method, and the control method may be executed by the backlight discrimination device. Further, a program having the functions of the above-described embodiments may be used as a control program, and the control program may be executed by a computer included in the backlight discrimination device. The control program is recorded on a computer-readable recording medium, for example.

  The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various recording media, and the computer (or CPU, MPU, etc.) of the system or apparatus reads the program. To be executed.

DESCRIPTION OF SYMBOLS 1 Camera main body 2 Interchangeable lens 3 Flash apparatus 12 Image sensor 20 Focus detection sensor 26 Photometric sensor 41 Camera control part 43 Signal processing circuit 51 Lens control part 61 Flash control part

Claims (11)

A backlight discrimination device for discriminating whether or not a shooting scene is a backlight scene,
Photometric means for receiving an image obtained in the shooting scene, dividing the image into a plurality of photometric areas, and measuring luminance and color in each of the photometric areas to obtain luminance information and color information;
A luminance difference calculating means for obtaining a luminance difference indicating a luminance difference in the image according to the luminance information;
Specific color determination means for determining whether or not a first specific color predetermined in the photometric area and a second specific color different from the first specific color are detected according to the color information;
When performing a backlight scene determination process that determines whether or not the shooting scene is a backlight scene according to the luminance difference and a backlight determination threshold, when the region that is the second specific color is not detected, Backlight determination means for performing the backlight scene determination process by changing the backlight determination threshold according to the number of photometric areas that are the first specific color;
A backlight discrimination device characterized by comprising:   When the number of photometric areas that are the first specific color is equal to or greater than a predetermined number, the backlight determination unit is more than the case where the number of photometric areas that are the first specific color is less than the predetermined number. 2. The backlight discrimination apparatus according to claim 1, wherein the backlight scene determination process is performed by increasing a backlight judgment threshold. A focus detection means for detecting whether or not each of the focus detection areas corresponding to the photometry area is in focus;
The brightness difference calculating means obtains an in-focus brightness value indicating an average brightness value in the photometry area corresponding to the focus detection area in the focused state, and an average brightness value that is an average brightness value in the photometry area 3. The backlight discrimination device according to claim 1, wherein the brightness difference is obtained in accordance with the focus portion brightness value.   2. The backlight discrimination device according to claim 1, further comprising: a light emitting unit configured to perform flash light emission when an average luminance value, which is an average value of luminance in the photometric region, is less than a preset luminance value set in advance. If an average luminance value, which is an average value of luminance in the photometric area, is equal to or greater than a preset luminance value, luminance gradient information indicating the luminance gradient in the photometric area located on the top side and the ground side in the image is obtained. A brightness slope calculating means;
5. The backlight discrimination device according to claim 1, wherein the backlight judgment threshold is defined by the average brightness and the brightness slope information. Before SL backlight determining means, said second specific color by the specific color determination unit is detected and the reliability of the detected said second metering area is a particular color has been is not less than a predetermined value, the backlight The backlight determination threshold value used in the scene determination process is made smaller than the backlight determination threshold value used when the number of photometric areas that are the first specific color is equal to or greater than a predetermined number. The backlight discrimination device according to any one of the preceding claims.   When the second specific color is detected by the specific color determination unit, the luminance difference calculating unit obtains a specific color luminance value indicating an average value of luminance in a photometric area that is the second specific color, 7. The backlight discrimination apparatus according to claim 6, wherein the luminance difference is obtained according to an average luminance value that is an average value of luminance in the photometric area and the specific color luminance value.   8. The backlight discrimination device according to claim 6, wherein the first specific color is green and the second specific color is a skin color. The backlight discrimination device according to any one of claims 1 to 8,
Imaging means for capturing an image of a subject and obtaining an image;
When it is determined by the backlight determination means that the scene is a backlight scene, light emission control means for controlling the flash to emit light,
An imaging device comprising: A method for controlling a backlight discrimination device for discriminating whether or not a shooting scene is a backlight scene,
A photometric step of receiving the image obtained in the shooting scene, dividing the image into a plurality of photometric areas, and measuring the luminance and color in each of the photometric areas to obtain luminance information and color information;
A luminance difference calculating step for obtaining a luminance difference indicating a luminance difference in the image according to the luminance information;
First and second different specific color determination step of determining whether the specific color is detected from the specific color you and the first specific color predetermined in the photometric area depending on the color information,
When performing a backlight scene determination process that determines whether or not the shooting scene is a backlight scene according to the luminance difference and a backlight determination threshold, when the region that is the second specific color is not detected, A backlight determination step of performing the backlight scene determination process by changing the backlight determination threshold according to the number of photometric areas that are the first specific color;
A control method characterized by comprising: A control program used in a backlight discrimination device that discriminates whether or not a shooting scene is a backlight scene,
In the computer provided in the backlight discrimination device,
A photometric step of receiving the image obtained in the shooting scene, dividing the image into a plurality of photometric areas, and measuring the luminance and color in each of the photometric areas to obtain luminance information and color information;
A luminance difference calculating step for obtaining a luminance difference indicating a luminance difference in the image according to the luminance information;
First and second different specific color determination step of determining whether the specific color is detected from the specific color you and the first specific color predetermined in the photometric area depending on the color information,
When performing a backlight scene determination process that determines whether or not the shooting scene is a backlight scene according to the luminance difference and a backlight determination threshold, when the region that is the second specific color is not detected, A backlight determination step of performing the backlight scene determination process by changing the backlight determination threshold according to the number of photometric areas that are the first specific color;
A control program characterized by causing