JP5304295B2 - Imaging device and white balance bracketing shooting program - Google Patents

Description

  The present invention relates to an imaging apparatus having a white balance bracketing shooting function, such as a digital camera, and a white balance bracketing shooting program.

  Conventionally, some digital cameras have a white balance (WB) bracketing photographing function for photographing a plurality of images having different color temperatures with one photographing instruction.

  As an example, for example, in Patent Document 1, in addition to an image of a color temperature determined by the camera or specified by the user with a single shooting instruction, another color temperature having similar color temperature and spectral characteristics is disclosed. A camera device having a WB bracketing shooting function of shooting the image is disclosed.

JP 2006-186931 A

  By using this WB bracketing shooting function, the user can acquire an image adjusted to a desired color temperature from among a plurality of shot images.

  By the way, in the case where shooting is performed by emitting flash light under a fluorescent lamp in a room, there is a problem that a color feria partially occurs in the shot image. This is because the conventional digital camera has a different color temperature between the subject light (the reflected light of the flash light from the subject) and the background light (the reflected light of the fluorescent light and / or the fluorescent light from the background). This is because the white balance of the image is adjusted in accordance with either one of the color temperatures.

  This point is the same also in the above-mentioned WB bracketing photography, and as a result, the user cannot acquire an image adjusted to a desired color temperature.

  In particular, with the recent increase in sensitivity of digital cameras, the influence of background light has increased and the problem has become apparent, but the conventional technology has not been able to solve it.

  The present invention is to solve the above-mentioned problems of the prior art. An object of the present invention is to provide an imaging device and a white balance bracketing imaging program that can acquire an image adjusted to a color temperature desired by a user.

  An imaging apparatus according to a first aspect includes a first calculation unit, a second calculation unit, and a generation unit. The first calculating means calculates a white balance (WB) gain B with respect to the background light based on the preliminary image captured without emitting flash light, and emits flash light immediately after capturing the preliminary image. The luminance of the main image and the preliminary image are compared, and the WB gain S for the subject light is calculated based on the image data of the area in the main image where the luminance difference exceeds a predetermined threshold. Further, the second calculation means has a plurality of values different from each other on the basis of the WB gain B and the WB gain S calculated by the first calculation means and a predetermined WB gain F for the flash light. WB gain is calculated. Then, the generating unit individually applies the plurality of WB gains calculated by the second calculating unit to the main image to generate a plurality of images (bracket images) having different color temperatures.

  According to a second invention, in the first invention, the second calculation means is configured to apply the WB gain F, the WB gain S, and the WB to the first, center, and last steps among a plurality of steps provided at equal intervals, respectively. A plurality of WB gains are calculated by setting the gain B as a reference and calculating the WB gain for the remaining steps based on the reference WB gain.

  In a third aspect based on the second aspect, the second calculating means is located between the step in which the WB gain F is set and the step in which the WB gain S is set among the remaining steps. For the step, the WB gain is calculated based on the WB gain F and the WB gain S, and among the remaining steps, the step in which the WB gain S is set and the WB gain B are set. WB gain is calculated based on the WB gain S and the WB gain B for the steps located between these steps.

  A fourth invention further comprises a display means for comparing and displaying a plurality of bracket images generated by the generating means in any one of the first to third inventions, and the display means comprises a plurality of sheets. By displaying the bracket images in a two-dimensional arrangement in the arrangement order based on the magnitude of the value of the WB gain, the difference in color temperature between the images is compared and displayed.

  According to a fifth aspect, in the fourth aspect, the display means moves from the left to the right of the screen in order from the smallest to the largest gb value of the WB gain, and from the top to the bottom of the screen. By displaying a plurality of bracket images side by side in the order from the smallest gain value to the largest one, the difference in color temperature between the images is displayed in comparison.

  A white balance bracketing shooting program according to a sixth aspect of the invention calculates a WB gain B with respect to background light based on a preliminary image shot without emitting flash light, and emits flash light immediately after shooting the preliminary image. The first calculation is performed to compare the luminance of the main image captured in advance and the preliminary image, and calculate the WB gain S for the subject light based on the image data of the region in the main image where the luminance difference exceeds a predetermined threshold. A plurality of WB gains having different values are calculated based on the procedure, the WB gain B and the WB gain S calculated by the first calculation procedure, and a predetermined WB gain F for the flash light. A plurality of bracket images having different color temperatures by individually applying the plurality of WB gains calculated by the second calculation procedure and the second calculation procedure to the main image. To execute a generating step of generating in the computer.

  In a seventh aspect based on the sixth aspect, the second calculation procedure is for the first step, the center step, and the last step among a plurality of steps provided at equal intervals, respectively, WB gain F, WB gain S, and WB. A plurality of WB gains are calculated by setting the gain B as a reference and calculating the WB gain for the remaining steps based on the reference WB gain.

  In an eighth aspect based on the seventh aspect, the second calculation procedure is positioned between the step in which the WB gain F is set and the step in which the WB gain S is set among the remaining steps. For the step, the WB gain is calculated based on the WB gain F and the WB gain S, and among the remaining steps, the step in which the WB gain S is set and the WB gain B are set. WB gain is calculated based on the WB gain S and the WB gain B for the steps located between these steps.

  According to a ninth invention, in any one of the sixth to eighth inventions, the computer further executes a display procedure for comparing and displaying a plurality of bracket images generated by the generating procedure, and the display procedure is A plurality of bracket images are displayed in a two-dimensional arrangement in the arrangement order based on the magnitude of the value of the WB gain, thereby comparing and displaying the difference in color temperature between the images.

  According to a tenth aspect, in the ninth aspect, the display procedure is performed from the left to the right of the screen in the order from the smallest WB gain gb value to the largest, and from the top to the bottom of the screen. By displaying a plurality of bracket images side by side in the order from the smallest gain value to the largest one, the difference in color temperature between the images is displayed in comparison.

  In the present invention, a white balance (WB) gain B with respect to background light is calculated based on the preliminary image. Also, the luminance of the main image and the preliminary image are compared, and the WB gain S for the subject light is calculated based on the image data of the area in the main image where the luminance difference exceeds a predetermined threshold. Note that the preliminary image is an image shot without flash light emission, and the main image is an image shot with flash light emission immediately after shooting the preliminary image.

  Then, a plurality of WB gains having different values are calculated based on the WB gain B, the WB gain S, and a predetermined WB gain F for the flash light. The WB gain calculated in this way takes into account the color temperatures of both subject light and background light, and both subject light and flash light.

  Thereafter, the plurality of calculated WB gains are individually applied to the main image to generate a plurality of bracket images having different color temperatures. The bracket image generated in this way is an image that has no color feria or a feeling of discomfort due to the color feria partially generated.

  Therefore, if the present invention is used, an image adjusted to the color temperature desired by the user can be acquired.

It is a block diagram which shows the structure of the digital camera of embodiment. It is a flowchart which shows the operation | movement of WB bracketing imaging | photography which a digital camera performs. It is a figure explaining the calculation method of the gain curve of WB gain. It is a figure which shows the display method of a bracket image.

  Embodiments of the present invention will be described below. The present embodiment is an embodiment of a digital camera.

  FIG. 1 is a block diagram showing the configuration of the digital camera of this embodiment.

  The digital camera includes a photographing lens 11 and a lens driving unit 12, an image sensor 13, an analog signal processing unit 14, a timing generator (TG) 15, a buffer memory 16, an image processing unit 17, a monitor 18, and a control. A unit 19, a photometric unit 20, a compression / decoding unit 21, a recording medium 22, a light emitting unit 23, an operation unit 24, and a bus 25. Here, the buffer memory 16, the image processing unit 17, the monitor 18, the control unit 19, the photometry unit 20, the compression / decoding unit 21, and the recording medium 22 are connected via a bus 25. Further, the lens driving unit 12, the analog signal processing unit 14, the TG 15, the light emitting unit 23, and the operation unit 24 are each connected to the control unit 19.

  The photographing lens 11 includes a plurality of lens groups including a focus lens and a zoom lens. For the sake of simplicity, FIG. 1 shows the photographing lens 11 as a single lens.

  The lens driving unit 12 generates a lens driving signal in accordance with an instruction from the control unit 19, moves the photographing lens 11 in the optical axis direction to perform focus adjustment and zoom adjustment, and subjects the light flux that has passed through the photographing lens 11 to the subject. An image is formed on the light receiving surface of the image sensor 13.

  The image sensor 13 is a CCD type or CMOS type image sensor, and is disposed on the image space side of the photographing lens 11. The image sensor 13 photoelectrically converts a subject image formed on the light receiving surface to generate an analog image signal. The output of the image sensor 13 is connected to an analog signal processing unit 14.

  The analog signal processing unit 14 performs analog signal processing such as CDS (correlated double sampling), gain adjustment, and A / D conversion on the analog image signal output from the image sensor 13 in accordance with an instruction from the control unit 19. And the processed image signal is output. The analog signal processing unit 14 sets an adjustment amount for gain adjustment based on an instruction from the control unit 19, and thereby adjusts imaging sensitivity corresponding to ISO sensitivity. The output of the analog signal processing unit 14 is connected to the buffer memory 16.

  The TG 15 supplies timing pulses to the image sensor 13 and the analog signal processing unit 14 based on instructions from the control unit 19. The drive timing of the image sensor 13 and the analog signal processing unit 14 is controlled by the timing pulse.

  The buffer memory 16 temporarily stores the image signal output from the analog signal processing unit 14 as image data. The buffer memory 16 temporarily stores image data created in the course of processing by the control unit 19.

  The image processing unit 17 performs image processing such as white balance adjustment, color separation (interpolation), edge enhancement, and gamma correction on the image data in the buffer memory 16 in accordance with an instruction from the control unit 19. The white balance (WB) adjustment is performed by the image processing unit 17 multiplying the R component and the B component of the image data by the WB control value (WB gain: gr, gb) calculated or acquired by the control unit 19. Do. The image processing unit 17 is configured as an ASIC or the like.

  The monitor 18 is an LCD monitor provided on the back surface of the digital camera housing or the like, an electronic viewfinder having an eyepiece, and the like, and displays various images according to instructions from the control unit 19.

  In accordance with an instruction from the control unit 19, the photometry unit 20 is based on the image data in the buffer memory 16, and uses a known photometry method such as multi-segment photometry (multi-pattern photometry), center-weighted photometry, spot photometry, An evaluation value indicating the overall brightness or the brightness distribution of the shooting scene is calculated.

  The compression / decoding unit 21 performs compression processing on the image data in the buffer memory 16 in accordance with an instruction from the control unit 19. The compression process is performed in JPEG (Joint Photographic Experts Group) format or the like.

  Further, the compression / decoding unit 21 is configured to be able to perform lossless compression (so-called lossless encoding).

  The recording medium 22 includes a memory card, a small hard disk, an optical disk such as a DVD, and the like. Note that the recording medium 22 may be built in the digital camera, may be detachably mounted, or may be provided outside. When provided outside, the recording medium 22 and the digital camera are electrically connected by wire or wireless.

  The light emitting unit 23 drives an electronic flash or the like provided in the digital camera housing based on an instruction from the control unit 19 to emit flash light for illuminating the subject toward the object scene.

  The operation unit 24 includes various operation members such as a mode setting button and a release button, and sends an operation signal corresponding to the content of the member operation by the user to the control unit 19.

  The control unit 19 comprehensively controls each unit of the digital camera according to the operation content of the operation member by the user.

  For example, when the digital camera is set to the shooting mode by operating the mode setting button or the like, the control unit 19 drives the lens driving unit 12, the analog signal processing unit 14, and the TG 15 to start shooting a through image. At this time, the image sensor 13 is driven in the draft mode (decimation readout mode), and the image data of the through image is sequentially recorded in the buffer memory 16 via the analog signal processing unit 14. The control unit 19 performs focus adjustment control (AF) of the imaging lens 11 in cooperation with the lens driving unit 12 based on the image data of the through image. Further, when the control unit 19 drives the photometry unit 20 to calculate the evaluation value of the subject or the shooting scene based on the image data of the through image in the buffer memory 16, the analog signal processing unit 14 and the like are based on the evaluation value. Adjust the settings of. Further, the control unit 19 drives the image processing unit 17 to perform image processing on the image data of the through image in the buffer memory 16, and sequentially displays the image data of the through image after the image processing on the monitor 18 (live). View display).

  Next, when the release button is pressed halfway in the shooting mode, the control unit 19 performs focus adjustment control (AF) of the imaging lens 11 in cooperation with the lens driving unit 12 prior to the main shooting.

  When the release button is fully pressed in the shooting mode, the control unit 19 determines shooting conditions (aperture value, shutter speed, presence / absence of flash emission, etc.) based on the evaluation value calculated by the photometry unit 20. Then, the control unit 19 drives the lens driving unit 12, the analog signal processing unit 14, and the TG 15 (and the light emitting unit 23 as necessary) under the determined shooting conditions to perform the main shooting. At this time, the image sensor 13 is driven in a frame mode (all pixel readout mode), and the image data of the captured main image is recorded in the buffer memory 16 via the analog signal processing unit 14. Thereafter, the control unit 19 drives the image processing unit 17 to perform image processing on the image data of the main image recorded in the buffer memory 16. In addition, the control unit 19 displays the main image after the image processing on the monitor 18. Then, the control unit 19 drives the compression / decoding unit 21 to perform compression processing on the image data of the main image after image processing and record the image data of the main image after compression processing on the recording medium 22. . However, when the digital camera is set to the uncompressed recording mode, the control unit 19 does not drive the compression / decoding unit 21, and the image data of the main image after image processing is recorded in the uncompressed recording medium. Record to 22.

  In the above operation, the white balance (hereinafter referred to as WB) adjustment in the image processing unit 17 for the through image and the main image is performed as follows according to the WB mode setting of the digital camera.

  When the WB mode of the digital camera is set to the “preset WB mode”, the WB adjustment in the image processing unit 17 is performed using the main image (white reference as a white reference) acquired by photographing an achromatic subject over the entire screen. This is performed using the WB control value calculated by the control unit 19 based on the image data of the “preset image”. The achromatic subject is, for example, white or gray paper given by the user in advance.

  When the WB mode is set to “manual WB mode”, the WB adjustment in the image processing unit 17 is performed according to the type of manual WB mode set by the user (for example, “fine weather”, “cloudy sky”, “ This is performed using the WB control value acquired by the control unit 19 according to “fluorescent lamp”, “bulb”, “flash”, and the like. The WB control value for the manual WB mode is determined in advance for each type and stored in a ROM (not shown) or the like.

  When the WB mode is set to “auto WB mode”, the WB adjustment in the image processing unit 17 is performed by using the WB control value calculated in real time by the control unit 19 based on the image data of the through image or the main image. Done with.

  By the way, the digital camera of this embodiment has a function of white balance (WB) bracketing shooting. As described above, if the WB bracketing shooting function is used, a plurality of images (bracket images) having different color temperatures can be shot with a single shooting instruction.

  Hereinafter, the operation performed by the digital camera according to the present embodiment for this function will be described with reference to the flowchart of FIG. The flowchart in FIG. 2 is executed when the user fully presses the release button and instructs the digital camera to perform main shooting when the WB bracketing shooting function is set to be valid.

  Here, it is assumed that the flash emission mode of the digital camera is set to the manual emission mode.

  Step 101 (S101): The control unit 19 performs preliminary shooting prior to actual shooting. This preliminary shooting is performed in order to calculate the WB gain (WB gain B) for the background light of the object scene. That is, in the digital camera, an image acquired by preliminary shooting is used for calculating the WB gain B. Therefore, flash light is not emitted during preliminary shooting. In this preliminary shooting, as in the main shooting, the image sensor 13 is driven in the all-pixel readout mode. Then, image data of an image acquired by preliminary shooting (hereinafter referred to as a preliminary image) is recorded in the buffer memory 16.

  Step 102: The control unit 19 performs the main shooting after the preliminary shooting. At this time, the control unit 19 drives the light emitting unit 23 to emit flash light. The image data of the main image acquired by the main shooting is recorded in a different area from the preliminary image in the buffer memory 16. In the digital camera, the main image acquired in this way is used to calculate a WB gain (WB gain S) for subject light in the object scene.

  Step 103: The control unit 19 calculates the WB gain B with respect to the background light based on the preliminary image (no flash emission) in the buffer memory 16 by auto white balance (AWB) calculation.

  Step 104: The control unit 19 calculates the WB gain S for the subject light based on the main image (with flash emission) in the buffer memory 16 by AWB calculation.

  Specifically, the control unit 19 compares the luminance of the main image (with flash emission) and the preliminary image (without flash emission) in the buffer memory 16 and the main image in which the luminance difference exceeds a predetermined threshold value. Extract the area inside. And the control part 19 calculates WB gain S with respect to object light based on the image data of the extracted area | region by AWB calculation.

  Step 105: The control unit 19 acquires a WB gain (WB gain F) predetermined for “flash” in the manual WB mode from a ROM (not shown) or the like. Then, the control unit 19 calculates a gain curve of the WB gain for the bracket image on the basis of the three WB gains of the WB gain F and the WB gain B and WB gain S calculated above.

  Here, an example of the calculation method will be described with reference to FIG. In the following description, it is assumed that the number of bracket image acquisitions (indicating the number of correction steps) is “5”. Note that the number of bracket images acquired can be specified in advance by the user via the menu screen of the digital camera or the like.

  First, as shown in FIG. 3A, “5” steps are provided at equal intervals on the horizontal axis of the graph based on the number of bracket image acquisitions (the number of correction steps). Then, the value of WB gain F and the value of WB gain B are respectively set at the first and last among a plurality of steps provided at equal intervals, that is, the “1” step and the “5” step in FIG. Set the value as a reference point. Further, at the center of the plurality of steps provided at equal intervals, that is, the “3” step corresponding to the intermediate position between the “1” step and the “5” step in FIG. The value of S is set as a reference point. In addition, about the space | interval (distance) between steps, the difference or ratio of the value of WB gain F and WB gain S used as the reference point of WB gain calculation, and the difference of the value of WB gain S and WB gain B Alternatively, it is determined according to the ratio.

  Next, on the horizontal axis, a step located between the step in which the value of the WB gain F is set and the step in which the value of the WB gain S is set, that is, the “2” step in FIG. , A value (WB gain) obtained by linear interpolation from the WB gain F and the WB gain S is set in the graph. On the horizontal axis, the step located between the step where the value of the WB gain S is set and the step where the value of the WB gain B is set, that is, the “4” step in FIG. A value (WB gain) obtained by linear interpolation from the WB gain S and the WB gain B is set in the graph.

  In this way, the gain curve of the WB gain for the bracket image shown in FIG. 3 (2) is calculated.

  Step 106: The control unit 19 creates a copy of the main image in the buffer memory 16. Note that copies are created for the number of bracket images acquired, or “the number of acquisitions−1”.

  When the control unit 19 acquires the WB gain corresponding to each correction step from the gain curve, the control unit 19 drives the image processing unit 17 to copy the main image in the buffer memory 16 or the main image in the buffer memory 16 and its image. Make white balance adjustment for each copy.

  In this way, the control unit 19 applies the WB gain acquired from the gain curve to the main image to generate a bracket image (a plurality of images).

  In the example of FIG. 3, the number of correction steps indicated on the horizontal axis in FIG. 3 (2), that is, “5” WB gains are acquired. Therefore, in the example of FIG. 3, “5” bracket images having different color temperatures are generated.

  Step 107: The control unit 19 drives the image processing unit 17, and is necessary for each copy of the main image in the buffer memory 16 or the main image and its copy in the buffer memory 16, that is, the generated bracket image. Image processing.

  Then, the control unit 19 displays the bracket image after image processing on the monitor 18. At this time, all the bracket images may be displayed at a time, or n bracket images may be displayed at a time (n is 1 or more).

  Step 108: The control unit 19 drives the compression / decoding unit 21 to perform compression processing on each bracket image after image processing.

  Then, the control unit 19 records the compressed bracket image on the recording medium 22. At this time, all the bracket images may be recorded on the recording medium 22 or, of the bracket images, only those designated by the user from, for example, a GUI screen displayed on the monitor 18 are recorded on the recording medium 22. It may be recorded.

  In this way, the control unit 19 captures a plurality of bracket images having different color temperatures.

(Supplementary items of the embodiment)
If a bracket image is generated using only a copy of the main image in step 106, the remaining main image is recorded on the recording medium 22 as RAW format image data in step 108. May be. At the time of the recording, it is preferable to record at least the values of the WB gain S and the WB gain B calculated above together with the image data. If the image file is based on the Exif standard, for example, those values are recorded as tag information of the image file. When the program related to the WB bracketing shooting operation is executed by an external processing device such as a computer, if the image file of the RAW format main image is input, the digital camera of this embodiment Similarly, a plurality of bracket images having different color temperatures can be generated by the external processing device.

  In the present embodiment, bracket images for the number of correction steps are generated. However, bracket images may be generated for all combinations of the WB gain gr and gb values set in the correction step. That is, a bracket image corresponding to the square of the number of correction steps may be generated. In this case, for example, in the example of FIG. 3B, the WB gains “gr1, gb1” to “gr1, gb5”, “gr2, gb1” to “gr2, gb5”, “gr3, gb1” to “gr3, Generate a bracket image for each of “gb5”, “gr4, gb1” to “gr4, gb5”, “gr5, gb1” to “gr5, gb5” (the numbers at the end of gr and gb indicate the number of steps) ). That is, 25 bracket images are generated. However, when there are a plurality of combinations having the same gr and gb values among all the combinations of the set WB gain gr and gb values, a bracket image is generated only for one of the same combinations. You may make it do.

  Further, when displaying the bracket images generated in this way, for example, the bracket images may be compared and displayed in an arrangement as shown in FIG. In other words, in the horizontal direction (row direction) of the screen, from the left to the right, the WB gain having the smallest gb value is displayed. Then, from the top to the bottom of the screen in the vertical direction (column direction), the WB gain with a smaller gr value is displayed. If the bracket images are compared and displayed in such an arrangement, the difference in color temperature between the images becomes easy to understand. Therefore, the user has adjusted the desired color temperature from a plurality of bracket images with different color temperatures. It makes it easier to recognize and find images.

  In the present embodiment, the WB gain (WB gain B) for the background light is calculated from the preliminary image that does not emit the flash. However, instead of the preliminary image, the WB gain B may be calculated using a through image acquired without flashing immediately before the main photographing. However, since the through image is subjected to white balance adjustment, when using the through image, WB calculated by AWB (auto white balance) calculation when white balance adjustment is performed on the through image to be used. The gain is acquired, and the WB gain is recorded in a memory (not shown) or the like. Then, the processing of step 101 is skipped without being executed, and the WB gain recorded in the memory (not shown) is acquired in step 103 and used as the WB gain B. do it.

(Effect of embodiment)
As described above, in the digital camera of the present embodiment, first, preliminary shooting is performed without emitting flash light, and immediately after that, main shooting is performed by emitting flash light, and a preliminary image (without flash emission) is obtained. A main image (with flash emission) is acquired.

  Next, the WB gain B with respect to the background light is calculated based on the preliminary image by auto white balance (AWB) calculation. Further, the luminance of the main image and the preliminary image are compared, and an area where the luminance difference exceeds a predetermined threshold is extracted from the main image. Then, the WB gain S for the subject light is calculated by the AWB calculation based on the image data of the extracted area.

  Thereafter, a gain curve of the WB gain for the bracket image is calculated on the basis of the WB gain B, the WB gain S, and the predetermined WB gain F for the flash light, and each obtained from the gain curve is calculated. By applying each WB gain corresponding to the correction step to the main image, a plurality of bracket images having different color temperatures are generated.

  From the gain curve, an intermediate value between the WB gain S for the subject light and the WB gain B for the background light, or an intermediate value between the WB gain S for the subject light and the WB gain F for the flash light. Is obtained as a WB gain for generating a bracket image. In this case, the WB gain takes into account the color temperatures of both subject light and background light, and both subject light and flash light. For example, when photographing is performed by emitting flash light under a fluorescent lamp indoors, subject light (reflected light of flash light by the subject) and background light (reflected light of fluorescent lamp light and / or fluorescent lamp light by a background object) The WB gain considering both color temperatures is acquired.

  For this reason, the bracket image generated by applying the acquired WB gain is an image in which there is no occurrence of color failure or there is little discomfort due to color failure that occurs partially. That is, an image adjusted to the color temperature desired by the user is generated.

  Therefore, according to the digital camera of this embodiment, an image adjusted to the color temperature desired by the user can be acquired.

(Other)
Of the programs relating to the WB bracketing shooting operation of the digital camera described above, the processes in steps 103 to 108 may be executed by an external processing device such as a computer. In that case, a necessary program is installed in the external processing apparatus via a computer-readable storage medium such as a CD-ROM or a communication network such as the Internet.

  However, in such a case, the preliminary image (flash non-emission) and the main image (flash emission) taken by an imaging device such as a digital camera are input to an external processing device that executes the program. Alternatively, the preliminary image and the main image are taken by an imaging device such as a digital camera, and further, the WB gain (WB gain B) with respect to the background light is calculated based on the preliminary image by AWB (auto white balance) calculation. Then, the captured main image and its WB gain B are input to the external processing device. In this case, the external processing apparatus executes the processing from step 104 to step 108 of the program. Alternatively, a preliminary image and a main image are taken by an imaging device such as a digital camera, and further, by AWB calculation, a WB gain B is obtained based on the preliminary image, and a WB gain (WB gain S is applied to the subject light based on the main image). ) Is calculated. Then, the captured main image and the WB gain B and WB gain S are input to the external processing device. In this case, the external processing apparatus executes the processing from step 105 to step 108 of the program.

  In the above description, the embodiment of the digital camera (digital still camera) has been described. However, the present invention can also be applied to other devices capable of taking a still image, such as a mobile phone or a digital video camera. .

DESCRIPTION OF SYMBOLS 11 ... Shooting lens, 12 ... Lens drive part, 13 ... Image sensor, 14 ... Analog signal processing part, 15 ... Timing generator (TG), 16 ... Buffer memory, 17 ... Image processing part, 18 ... Monitor, 19 ... Control part , 20 ... Metering section, 21 ... Compression / decoding section, 22 ... Recording medium, 23 ... Light emitting section, 24 ... Operation section, 25 ... Bus

Claims (10)

A white balance gain B with respect to background light is calculated based on a preliminary image captured without flash light being emitted, and the main image and the preliminary image captured with flash light immediately after the preliminary image is captured, First calculating means for comparing the brightness of the subject light and calculating a white balance gain S for the subject light based on image data of an area in the main image in which the brightness difference exceeds a predetermined threshold value;
A plurality of white balance gains having different values are calculated on the basis of the gain B and the gain S calculated by the first calculation means and a predetermined white balance gain F for flash light. Two calculating means;
And generating means for generating a plurality of bracket images having different color temperatures by individually applying the plurality of white balance gains calculated by the second calculating means to the main image. Imaging device. The imaging device according to claim 1,
The second calculation means sets the gain F, the gain S, and the gain B as a reference for the first, center, and last steps among a plurality of steps provided at equal intervals, and the rest An image pickup apparatus, wherein the plurality of white balance gains are calculated by calculating a white balance gain for the step based on the reference. The imaging device according to claim 2,
The second calculation means, for the steps located between the step in which the gain F is set and the step in which the gain S is set, among the remaining steps, A white balance gain is calculated based on the gain S, and among the remaining steps, a step positioned between the step in which the gain S is set and the step in which the gain B is set Calculates a white balance gain based on the gain S and the gain B. An imaging apparatus, wherein: In the imaging device according to any one of claims 1 to 3,
A display unit for comparing and displaying the plurality of bracket images generated by the generation unit;
The display means displays the plurality of bracket images in a two-dimensional arrangement in the arrangement order based on the magnitude of the white balance gain value, thereby comparing and displaying the difference in color temperature between the images. An imaging device that is characterized. The imaging apparatus according to claim 4,
The display means, in order from the left to the right of the screen, from the smallest white balance gain gb value to the largest, and from the top to the bottom of the screen from the smallest white balance gain gr value to the largest. An imaging apparatus, wherein the plurality of bracket images are displayed side by side in the order of the objects, thereby comparing and displaying the difference in color temperature between the images. A white balance gain B with respect to background light is calculated based on a preliminary image captured without flash light being emitted, and the main image and the preliminary image captured with flash light immediately after the preliminary image is captured, A first calculation procedure for calculating a white balance gain S for subject light based on image data of an area in the main image in which the luminance difference exceeds a predetermined threshold value;
A plurality of white balance gains having different values are calculated on the basis of the gain B and the gain S calculated by the first calculation procedure and a predetermined white balance gain F for flash light. 2 calculation procedures;
Generating a plurality of bracket images having different color temperatures by individually applying the plurality of white balance gains calculated by the second calculation procedure to the main image, and causing the computer to execute the generation procedure. White balance bracketing shooting program. In the white balance bracketing shooting program according to claim 6,
The second calculation procedure sets the gain F, the gain S, and the gain B as references for the first, center, and last steps among a plurality of steps provided at equal intervals, and the rest The white balance bracketing photographing program, wherein the white balance gain for the step is calculated based on the reference to calculate the plurality of white balance gains. In the white balance bracketing photography program according to claim 7,
In the second calculation procedure, among the remaining steps, for the step positioned between the step in which the gain F is set and the step in which the gain S is set, the gain F and the A white balance gain is calculated based on the gain S, and among the remaining steps, a step positioned between the step in which the gain S is set and the step in which the gain B is set Calculates a white balance gain based on the gain S and the gain B. A white balance bracketing imaging program. In the white balance bracketing shooting program according to any one of claims 6 to 8,
Further causing the computer to execute a display procedure for comparing and displaying a plurality of bracket images generated by the generating procedure,
The display procedure includes displaying the plurality of bracket images in a two-dimensional arrangement in the arrangement order based on the magnitude of the value of the white balance gain, and comparing and displaying the difference in color temperature between the images. Characteristic white balance bracketing shooting program. The white balance bracketing shooting program according to claim 9,
The display procedure is from the left to the right of the screen in the order from the smallest white balance gain gb value to the largest, and from the top to the bottom of the screen from the smallest white balance gain gr value. A white balance bracketing photographing program, wherein the plurality of bracket images are displayed side by side in the order of the objects, thereby comparing and displaying the difference in color temperature between the images.

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