JP3974799B2 - Digital camera - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  This inventionIs daThe present invention relates to a digital camera capable of selectively switching between an enlarged dynamic range shooting mode and a normal shooting mode.
[0002]
[Prior art]
  In general, a solid-state image pickup device such as a CCD image pickup device is used in a digital camera. However, there is a problem that the dynamic range of the solid-state image pickup device is extremely narrow compared to a silver salt photographic film. Thus, various techniques have been developed for expanding the dynamic range of digital cameras.
[0003]
  For example, as disclosed in Japanese Patent Laid-Open No. 2000-92378, a normal photographed image is obtained by performing a composition process by photographing a plurality of exposures with different exposure amounts, that is, long exposure and short exposure. There is a method to increase the dynamic range compared to In addition to the normal monitor gamma conversion curve, there is also known a method for expanding the dynamic range by performing adaptive gradation conversion according to the luminance distribution of the subject.
[0004]
[Problems to be solved by the invention]
  By the way, according to the above-mentioned dynamic range expansion method by multiple shooting, the dynamic range expansion effect is great, but it is not suitable for dynamic subjects and the exposure time is long, so that camera shake does not occur during shooting. There is a problem that it is necessary to pay attention to. Further, in the latter method of performing gradation conversion according to the luminance distribution to increase the dynamic range, there is no fear of camera shake or the like since the exposure is performed once, but the dynamic range is expanded by shooting the former multiple times. There is a problem that the enlargement effect cannot be obtained as much as by the method.
[0005]
  The present invention has been made to solve the above-mentioned problems in the conventional dynamic range expansion method of a digital camera, and is a digital camera capable of performing an appropriate dynamic range expansion process according to the luminance state of a subject. The purpose is to provide.
[0006]
[Means for Solving the Problems]
  In order to solve the above problems, the invention according to claim 1Taken imageDynamic range expansion means for expanding the dynamic range ofDynamic rangeA shooting mode selection unit that selects either a dynamic range expansion shooting mode for performing shooting using an expansion unit and a normal shooting mode that does not use the dynamic range expansion unit;A flash means for illuminating the subject and a backlight judgment means for judging whether or not the subject is in a backlight state, and the shooting mode selection means selects the dynamic range expansion shooting mode when the flash means is used in non-backlight. LikeIt constitutes a digital camera.
[0007]
  In the digital camera configured as described above, when the flash means is used during non-backlighting, the brightness of a part of the screen is increased by the flash, and the brightness difference in the screen is enlarged, but the dynamic range expansion shooting mode is selected. Thus, a high-quality image with an expanded dynamic range can be obtained.
[0008]
  The invention according to claim 2Luminance difference calculating means for calculating a luminance difference in the captured image, dynamic range expanding means for expanding the dynamic range of the captured image, and dynamic range expansion for performing shooting using the dynamic range expanding means based on the luminance difference A shooting mode selection unit for selecting one of a shooting mode and a normal shooting mode that does not use the dynamic range expansion unit;,Flashing means for irradiating the subject, and backlight determining means for determining whether or not the subject is in a backlight state,The shooting mode selection means includesThe above during backlightWhen using the flash means, based on the brightness difference obtained by the preliminary light emission of the flash means, the shooting modeTheChoiceTo configure the digital cameraTo do.
[0009]
  In the digital camera configured in this manner, the shooting mode is selected based on the luminance difference obtained by the preliminary light emission of the flash means, so that appropriate shooting corresponding to the subject mode at the time of actual flash light emission is performed. The photographing process can be performed by selecting the mode.
[0010]
  The invention according to claim 3 is claimed in claim2In the digital camera according to the present invention, the shooting mode selection means includesWhen the brightness difference is small,A normal shooting mode is selected.
[0011]
  When the flashing means is used during backlighting, the entire screen is properly exposed. However, in the digital camera having the above-described configuration, the normal shooting mode is selected, so that appropriate shooting processing can be performed.
[0012]
  The invention according to claim 4 is for measuring subject brightness,In the screenMetering means capable of selectively executing multi-point metering for measuring a plurality of points and one-point metering for metering one point in a screenA dynamic range expansion unit that expands a dynamic range of a captured image, a dynamic range expansion shooting mode that performs shooting using the dynamic range expansion unit when the multipoint metering is selected, and the dynamic range expansion unit. Select one of the normal shooting modes that will not be used,Select normal shooting mode when single-point metering is selectedDigital camera with shooting mode selection meansTo do.
[0013
  In the digital camera configured as described above, when one point (spot) metering is selected and designated in advance by the metering means, the image in the designated area only needs to be optimally exposed. By selecting, it is possible to perform an appropriate photographing process corresponding to the photographer's intention.
[0014]
  The invention according to claim 5First dynamic range expansion means for generating a single captured image by combining a plurality of captured images obtained with different exposure amounts for the same subject, and second dynamic range expansion for performing gradation conversion processing on the captured image Photographing that selects at least one of a dynamic range enlarging unit that has at least two enlarging units, a dynamic range enlarging photographing mode that performs photographing using the dynamic range enlarging unit, and a normal photographing mode that does not use the dynamic range enlarging unit Comprising mode selection means and flash means for irradiating the subject;The shooting mode selection means is configured to use the normal shooting mode and the second dynamic range when the flash means is used.Configure the digital camera to select one of the dynamic range expansion shooting modes that use the enlargement methodTo do.
[0015]
  When shooting is performed with the use of flash means, it is difficult to control multiple exposures. Therefore, as described above, when the flash means is used, by selecting one of the normal shooting mode and the second dynamic range mode, an appropriate shooting mode can be selected when using the flash.
[0016]
  The invention according to claim 6 is the claim5In the digital camera according to the above aspect, the digital camera includes a backlight determination unit that determines whether or not the subject is in a backlight state, and the shooting mode selection unit includes:When it is judged as non-backlight when using the flash meansIncludes the second dynamic range.Dynamic range enlargement using magnification meansA mode is selected.
[0017
  In the digital camera configured as described above, when the flash means is used at the time of non-backlight, the brightness of a part of the screen is increased by the flash and the brightness difference in the screen is enlarged, but the second dynamic range mode is set. Since the selection is made, it is possible to obtain an image with an appropriate wide dynamic range with high image quality when the flashing means is used during non-backlighting.
[0018]
  The invention according to claim 7 provides:First dynamic range expansion means for generating a single captured image by combining a plurality of captured images obtained with different exposure amounts for the same subject, and second dynamic range expansion for performing gradation conversion processing on the captured image Photographing that selects at least one of a dynamic range enlarging unit that has at least two enlarging units, a dynamic range enlarging photographing mode that performs photographing using the dynamic range enlarging unit, and a normal photographing mode that does not use the dynamic range enlarging unit Comprising mode selection means and flash means for irradiating the subject;The shooting mode selection means includesSaidWhen using flash meansWhen the dynamic range expansion photographing mode is selected, a mode in which the second dynamic range expansion unit is used as the dynamic range expansion unit is selected.selectTo configure a digital cameraIs.
[0019
  When shooting is performed with the use of flash means, it is difficult to control multiple exposures. Therefore, as described above, when the flash means is used, by selecting one of the normal shooting mode and the second dynamic range mode, an appropriate shooting mode can be selected when using the flash.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
  Next, embodiments will be described. FIG. 1 is a block diagram showing the electrical configuration of an embodiment of a digital camera according to the present invention. The solid line portion shows the flow of image signals and data, and the dotted line portion shows the flow of control signals. In FIG. 1, 1 is a lens system, 2 is an aperture, 3 is a single-plate color CCD image sensor, and the aperture 2 and the CCD image sensor 3 are controlled by a control signal from a control unit 8 such as a CPU, and the aperture control and exposure time. Control is to be performed. Reference numeral 4 denotes an A / D converter that converts an image pickup signal, which is an analog signal from the CCD image pickup device 3, into a digital signal. Reference numerals 5 and 6 denote a first image buffer and a second image buffer. Two image data obtained when the image is taken twice while changing is held.
[0021]
  Reference numeral 9 denotes an interpolation unit for generating color image data of one pixel and three colors from single-plate color RGB image data from the CCD image pickup device 3 held in the first and second image buffers 5 and 6. Therefore, the image data interpolated by the interpolation unit 9 is held in the work buffer 9. When the normal shooting mode is selected, the image data held in the work buffer 9 is directly input to the gamma conversion unit 16, gamma-converted by the gamma conversion unit 16, and then via the data output unit 17. It is to be recorded on the memory card.
[0022]
  On the other hand, when a wide dynamic range (hereinafter abbreviated as SL: Super Latitude) shooting mode is selected, the two image data held in the work buffer 9 are input to the Y / C separation unit 11 and the luminance Signal Y and color difference signal C_R, C_BSeparated. The luminance signal Y is input to the luminance correction unit 12, and luminance correction is performed. On the other hand, the color difference signal C_R, C_BIs input to the color difference correction unit 13, and color difference correction is performed. The corrected luminance signal and color difference signal are input to the Y / C synthesis unit 14 and synthesized again. The two pieces of image data that have been subjected to the above processes are input to the image composition unit 15, and a wide dynamic range composite image is generated. The SL composite image generated by the image composition unit 15 is subjected to gamma conversion processing by the gamma conversion unit 16 as in the normal photographing mode, and is recorded on the memory card via the data output unit 17.
[0023]
  In FIG. 1, reference numeral 10 denotes a photometric evaluation unit for controlling AE and selecting a shooting mode for performing normal shooting or SL shooting. That is, the CCD image pickup device 3 performs preliminary shooting for exposure control before the main shooting, obtains the luminance distribution of the subject using the image data, generates the AE control signal from the luminance distribution state, and selects the shooting mode. Is supposed to do. In FIG. 1, reference numeral 18 denotes an operation unit for performing various input operations on the control unit 8.
[0024]
  Next, the basic operation of the photographing process of the digital camera having the above configuration will be described based on the flowchart of FIG. As a photographing processing operation, first, it waits for the release of the camera to be turned on (step S1), and when the relays are turned on, an SL mode determination process is performed (step S2). Here, it is determined in which shooting mode shooting should be performed. Next, imaging processing is performed in the photographing mode set in the SL mode determination processing step (step S3). In the SL photographing mode, SL processing such as composition processing is performed (step S4), and then gamma is performed. After the conversion process is performed (step S5), the image data is output (step S6).
[0025]
  Next, the SL mode determination process will be described in detail based on the flowchart of FIG. First, photometric data is evaluated (step S11). In this photometric data evaluation step, first, as shown in FIG. 4, the image data for one screen obtained by the preliminary photographing is divided into a plurality of areas n, in this example, nine areas a1 to a9 of 3 × 3. The brightness value BVarea is calculated from the digital value of the image data for each area. Next, using these luminance values BVarea, an average value BVave = (ΣBVarea) / n is obtained, and a difference ΔBV between the maximum luminance value BVmax and the minimum luminance value BVmin is obtained.
[0026]
  In the photometric data evaluation step S11, a normal AE process is performed to calculate the combination of the aperture and shutter speed for the photographic subject, and based on this, it is determined whether or not the strobe needs to emit light (step S12). If the strobe light emission is not necessary, it is next determined whether or not the luminance difference ΔBV is larger than the first threshold Thresh1 (step S13). Here, when the luminance difference ΔBV is larger than the first threshold Thresh1, that is, when the luminance difference is large, photographing is performed in an SL photographing mode called SL2 (step S14). This SL shooting mode SL2 is a shooting mode in which exposure is performed twice and two shot images are combined.
[0027]
  In the determination step 13 for determining whether or not the luminance difference ΔBV is larger than the first threshold Thresh1, if the luminance difference ΔBV is smaller than the first threshold Thresh1, then whether or not the luminance difference ΔBV is larger than the second threshold Thresh2 Is determined (step S15). Here, the first threshold Thresh1> the second threshold Thresh2. In this determination step S15, when the luminance difference ΔBV is larger than the second threshold value Thresh2, shooting is performed in the SL shooting mode SL1 (step S16). This SL shooting mode SL1 is a shooting mode in which tone conversion processing is performed with an adaptive tone curve in accordance with the luminance distribution state of the subject after one exposure, although the exposure itself is once. The SL shooting mode SL1 will be described in detail later. Next, in step S15 for determining whether or not the luminance difference ΔBV is greater than the second threshold Thresh2, if the luminance difference ΔBV is smaller than the second threshold Thresh2, it is determined that the luminance difference is small, and the SL shooting mode is set. Is set to OFF, and the shooting process is executed in the normal shooting mode (step S17).
[0028]
  In step S12 for determining whether or not strobe light is required, if strobe light is required, it is next determined whether or not the subject is in a backlight state (step S18). If it is not backlit, shooting is performed in the SL shooting mode SL1 (step S19). If it is determined in step S18 whether or not the backlight is in the backlit state, the flash is Is preliminarily emitted (step S20), the luminance value of the subject is measured in advance from the return data at the time of flash emission, and the luminance difference ΔBVst at the time of flash emission is calculated (step S21).
[0029]
  Next, based on the calculated luminance difference ΔBVst at the time of flash emission, it is determined whether or not the following determination formulas (1) to (4) are satisfied (step S22). In addition, any of (1)-(4) can be used as a judgment formula.
        Judgment formula (1) ΔBVst <Thresh2
        Determination formula (2) ΔBV−ΔBVst <Thresh3
        Judgment formula (3) Judgment formula (1) or judgment formula (2)
        Judgment Formula (4) Judgment Formula (1) and Judgment Formula (2)
        However, Thresh2> Thresh3
[0030]
  Then, in the determination step S22 for determining whether or not the above-described determination formula is satisfied, if the determination formula is satisfied, it is determined that the luminance difference ΔBVst is small, and shooting is performed in the normal shooting mode without using the SL shooting mode ( In step S23), if the determination formula is not satisfied, the photographing process is performed in the SL photographing mode SL1 (step S19). As described above, when shooting with a strobe, it is difficult to control the double exposure, and at least the main subject is set to a proper exposure when using the strobe. Further, for the reason of power saving, the SL shooting mode SL2 is not used, and shooting is executed in either the SL shooting mode SL1 or the normal shooting mode in which the SL shooting mode is OFF.
[0031]
  Next, imaging process step S3 of the basic imaging process flow shown in FIG. 2 will be described in detail with reference to the flowchart of FIG. In this imaging processing step, it is first determined whether or not the SL shooting mode is the SL shooting mode SL2 (step S31). If it is the SL shooting mode SL2, based on the maximum luminance value BVmax and the luminance difference ΔBV. Thus, the short exposure time Tse is determined so as not to cause overexposure, and the long exposure time Tle is determined so as not to cause blackout (step S32). Then, two imaging operations of the determined short exposure time Tse and long exposure time Tle are executed (step S33).
[0032]
  In the determination step S31 of whether or not the SL shooting mode is the SL shooting mode SL2, if it is not the mode SL2, it is subsequently determined whether or not it is the SL shooting mode SL1 (step S34). In the case of the SL shooting mode SL1, the short exposure time Tse is determined based on the maximum luminance BVmax (step S35), and one imaging is performed with the short exposure time Tse (step S36). In step S34 for determining whether or not the SL shooting mode is the SL shooting mode SL1, if it is not the SL shooting mode SL1, the short exposure time Tse is determined using the average luminance BVave (step S37), and the short exposure time. One shooting is performed at Tse (step S36).
[0033]
  Next, the SL processing step S4 of the basic photographing processing flow shown in FIG. 2 will be described in detail based on the flowchart of FIG. Note that the flowchart of FIG. 6 shows the SL processing steps when the SL shooting mode SL2 is accompanied by the gradation conversion processing in the SL shooting mode SL1. In the SL processing operation in this case, it is first determined whether or not the SL shooting mode is OFF (step S41), and if the SL shooting mode is OFF, the process ends without doing anything. When the SL shooting mode is not OFF and the SL shooting mode is the mode SL1 or the mode SL2 accompanied by the mode SL1, first, the Y / C separation unit 11 converts the image data held in the work buffer 9 into a luminance signal. The color difference signal is separated (step S42).
[0034]
  Next, based on the separated luminance signal, as shown in FIG. 7, a histogram of pixel values indicating the relationship between the pixel value for one screen and the output frequency of the pixel value is generated (step S43). The histogram shown in FIG. 7 is an example on the assumption that a 10-bit A / D converter is used. Next, based on this histogram, a cumulative histogram as shown in FIG. 8 is generated (step S44). Then, a gradation conversion curve as shown in FIG. 9 is calculated based on the cumulative histogram (step S45), and the luminance correction unit 12 performs luminance conversion based on the gradation conversion curve (step S46).
[0035]
  Here, the example of the pixel value histogram shown in FIG. 7 is a histogram of an image with a large luminance difference and poor appearance in a backlight state or the like. By converting the gradation of such a histogram so that the peaks and valleys thereof are flattened, the dynamic range of the camera can be expanded as a result. In order to calculate a gradation conversion curve for performing such a histogram flattening process, a cumulative histogram is created as described above. Then, a gradation conversion curve corresponding to the cumulative histogram is calculated, and gradation conversion processing is performed based on the calculated gradation conversion curve, whereby the image is converted into an image that provides a flattened histogram.
[0036]
  Next, a color difference correction coefficient is calculated for the color difference signal separated by the Y / C separation unit 11 (step S47), and color difference correction is performed by the color difference correction unit 13 based on the color difference correction coefficient (step S48). ). The color difference correction coefficient has various expression formats, and is generally expressed by (luminance value Yproc after conversion) / (luminance value Yorg before conversion). Therefore, the color difference value Cprocess after color difference correction is expressed as follows, where Corg is the color difference value before correction.
        Cprocess = Corg × (Yproc / Yorg)
[0037]
  After performing the color difference correction process, the Y / C synthesis unit 14 again performs the synthesis process of the luminance signal and the color difference signal (step S49), and then determines whether or not the SL shooting mode is mode SL2. (Step S50) In the case of the SL shooting mode SL2, a composite process is performed after the same processing is performed on the image captured twice (step S51). On the other hand, in the case of the SL shooting mode SL1, the SL process is terminated after the process based on the gradation conversion is performed.
[0038]
  Next, in the SL processing, the operation when the SL shooting mode SL2 is only the double exposure composition processing and is not accompanied by the adaptive gradation conversion processing of the SL shooting mode SL1 will be described based on the flowchart shown in FIG. In this case, in step S41 for determining whether or not the SL shooting mode is OFF, if the SL shooting mode is not OFF and this SL shooting mode is selected, then the selected SL shooting mode is selected. A step S52 for determining whether or not the mode is the SL shooting mode SL1 is added. If the SL shooting mode SL1 is selected in this determination step S52, the adaptive gradation conversion processing operation from step S42 to step S49 is performed as in the processing shown in FIG. Exit. On the other hand, when the SL shooting mode is not the SL shooting mode SL1 but the SL shooting mode SL2 in the determination step S52, the adaptive gradation conversion process is not performed and the double exposure image combining process is directly performed ( Step S51), the SL process is terminated.
[0039]
  Next, the gamma conversion process of the basic imaging process flow shown in FIG. 2 will be described. This gamma conversion process is performed to correct the non-linear characteristics of the monitor display unit, and the conversion process is performed using a gamma conversion curve as shown in FIG.
[0040]
  Next, photographing processing when spot metering is performed will be described. There are two types of spot metering, multi-point spot metering and one-point spot metering. Then, the scanning unit 18 can select which of the spot metering types is used at the time of photographing.
[0041]
  First, photographing processing when multipoint spot metering is performed will be described. Some current cameras have a function in which a user designates a plurality of points of brightness of a subject and performs photometry, and determines an imaging condition based on an average value thereof. In the present invention, when such multi-point spot metering is performed, the photographing mode is adaptively applied so that the aspect of the subject including all the metering points is reproduced as much as possible.
[0042]
  FIG. 12A is a diagram showing a multi-point spot metering mode on the monitor screen 21. FIG. ●, ▲, ★ marks are photometry points designated by the user, and are displayed so that they can be confirmed on the monitor. Further, [] indicates an area for instructing spot metering on the monitor screen, and in the illustrated example, a mode for metering a person's face is shown. In addition, an exposure indicator 22 is displayed on the lower edge of the monitor screen 21 so as to display the luminance at the designated photometric position, etc. (B), (C), (D ) Shows the enlarged view. As shown in (B), (C), and (D) of FIG. 12, the exposure indicator 22 is graduated, and the central thick line 23 indicates the central value of the luminance of the designated multipoint spot measurement point. The positions indicated by ●, ▲, and ★ indicate the luminance values at the photometric positions, and the areas indicated by halftone dots indicate the imageable luminance ranges 24 in the respective photographing modes.
[0043]
  (B) in FIG. 12 shows a photographic possible luminance range in the normal photographing mode, and shows that this is applied when the widths of the luminances (BVmin, BVmax) at the measurement points ★ and ▲ are not wide. . (C) in FIG. 12 shows a photographic possible luminance range in the SL photographing mode SL1, and indicates that the present invention is applied when the luminance range of ★ and ▲ is slightly wide. (D) of FIG. 12 shows the photographic possible luminance range in the SL photographing mode SL2, and shows that the present invention is applied when the luminance range of ★ and ▲ is considerably wide. The selection criteria for each shooting mode is the same as the operation criteria in the SL mode determination process shown in FIG.
[0044]
  Next, the photographing processing operation at the time of multipoint spot metering will be described based on the flowchart shown in FIG. The photographing process at the time of multi-point spot metering is that the user designates multi-point spot metering and performs metering before the release is turned on, and performs SL mode determination processing. That is, the camera is provided with a spot metering button in addition to the release button, and the spot metering button is used to instruct and set the metering position desired by the user (step S61). Immediately based on the photometric result, SL mode determination processing is executed in the same steps as shown in FIG. 3 (step S62). In addition, what is calculated | required by following Formula is used as (DELTA) BV value here.
        ΔBV ＝ BVmax −BVmin
        ΔBV = (BVmax−BVave) × 2
        ΔBV = (BVave−BVmin) × 2
        However, BVave = (ΣBVspot) / n
[0045]
  Then, an exposure indicator corresponding to the selected photographing mode is displayed (step S63), and the process waits for the release to be turned on (step S64). As described above, when the release is turned off, the shooting mode has already been determined. When the release is turned on, the imaging process is performed in the same steps as shown in FIG. 5 (step S65), and then FIG. Alternatively, SL processing is performed in the same steps as shown in FIG. 10 (step S66), and image data is output (step S67).
[0046]
  Next, imaging processing when one-point spot metering is selected will be described. In the one-point spot metering, only the area indicated by [] in FIG. 12 is metered, and the luminance value is calculated. As described above, when the one-point spot metering is selected by the operation unit 18, the normal shooting mode is automatically selected as the shooting mode. In other words, one-point spot metering is performed so that the exposure condition is optimized in a specific area in the screen, so that the normal shooting mode is set in accordance with the photographer's intention to give priority to the specific area. To.
[0047]
  Next, the photographing processing operation at the time of one-point spot metering will be described based on the flowchart shown in FIG. At the time of this one-point spot metering, the user designates and sets only one point of the desired metering position with the button for spot metering (step S71), and when the metering is performed, the normal shooting mode is set based on the metering result. It waits for exposure conditions to be set and for the release to be turned on (step S72). When the release is turned on, normal shooting processing based on the normal shooting mode is performed (step S73), and image data is output (step S74).
[0048]
  In the description of the above embodiment, the control unit automatically selects and sets each shooting mode in accordance with the luminance difference of the subject. It can also be configured so that it can be set as appropriate by input from.
[0049]
【The invention's effect】
  As described above based on the embodiment,BookAccording to the invention,It is possible to provide a digital camera in which switching between the dynamic range expansion shooting mode and the normal shooting mode is appropriately performed.
[Brief description of the drawings]
FIG. 1 is a block configuration diagram showing an electrical configuration of an embodiment of a digital camera according to the present invention.
FIG. 2 is a flowchart for explaining a basic operation of shooting processing of the digital camera according to the embodiment shown in FIG. 1;
3 is a flowchart for explaining an operation of an SL mode determination process in the photographing processing operation shown in FIG.
FIG. 4 is a diagram illustrating a division mode of image data for one screen for calculating a luminance value in a photometric evaluation unit.
FIG. 5 is a flowchart for explaining an operation of an imaging process in the imaging process operation shown in FIG. 2;
6 is a flowchart for explaining an operation of SL processing in the photographing processing operation shown in FIG.
FIG. 7 is a diagram illustrating an example of a histogram representing a relationship between a pixel value for one screen and its output frequency.
8 is a diagram showing a cumulative histogram created from the histogram of FIG.
9 is a diagram showing a gradation conversion curve calculated based on the cumulative histogram shown in FIG. 8. FIG.
10 is a flowchart for explaining another example of the SL processing in the photographing processing operation shown in FIG. 2;
11 is a diagram illustrating a gamma conversion curve used in gamma conversion processing in the photographing processing operation illustrated in FIG. 2;
FIG. 12 is a diagram showing a monitor screen displaying a multi-point spot metering mode.
FIG. 13 is a flowchart for explaining a photographing processing operation at the time of multi-point spot metering.
FIG. 14 is a flowchart for explaining a photographing processing operation at the time of one-point spot metering.
[Explanation of symbols]
  1 Lens system
  2 Aperture
  3 CCD image sensor
  4 A / D converter
  5 First image buffer
  6 Second image buffer
  7 Interpolator
  8 Control unit
  9 Work buffer
  10 Photometric evaluation section
  11 Y / C separator
  12 Brightness correction section
  13 Color difference correction unit
  14 Y / C synthesis part
  15 Image composition part
  16 Gamma converter
  17 Data output section
  18 Operation unit
  21 Monitor screen
  22 Exposure indicator
  23 Brightness center value
  24 Captureable brightness range

Claims (7)

Dynamic range expansion means for expanding the dynamic range of the captured image ;
A photographing mode selecting means for selecting either the normal mode that does not use dynamic range widening photography mode and the dynamic range expansion means for performing photographing by using the dynamic range expansion means,
A flashing means for illuminating the subject;
A backlight determining means for determining whether or not the subject is backlit,
The digital camera according to claim 1, wherein the photographing mode selection means selects the dynamic range expansion photographing mode when the flash means is used during non-backlighting . A luminance difference calculating means for calculating a luminance difference in the captured image;
Dynamic range expansion means for expanding the dynamic range of the captured image;
Based on the brightness difference, a dynamic range expansion shooting mode for performing shooting using the dynamic range expansion unit, and a shooting mode selection unit for selecting either a normal shooting mode without using the dynamic range expansion unit ,
A flashing means for illuminating the subject;
A backlight determining means for determining whether or not the subject is backlit,
The photographing mode selection means when said flash unit used when backlit, on the basis of the brightness difference obtained by the preliminary light emission of the flash unit, features and to Lud digital camera to select the imaging mode. 3. The digital camera according to claim 2 , wherein the shooting mode selection unit selects a normal shooting mode when the brightness difference is small . A measures the subject brightness, the multi-point light measuring for metering a plurality of points of the screen, and capable of selectively executing photometry means a point and metering for metering a point in the screen,
Dynamic range expansion means for expanding the dynamic range of the captured image;
When the multi-point metering is selected, a dynamic range expansion photographing mode for performing photographing using the dynamic range expanding unit and a normal photographing mode not using the dynamic range expanding unit are selected, and the one-point metering is performed. A digital camera comprising shooting mode selection means for selecting a normal shooting mode when is selected. First dynamic range expansion means for generating a single captured image by combining a plurality of captured images obtained with different exposure amounts for the same subject, and second dynamic range expansion for performing gradation conversion processing on the captured image Dynamic range expansion means having at least two expansion means of the means;
A shooting mode selection unit that selects either a dynamic range expansion shooting mode for performing shooting using the dynamic range expansion unit and a normal shooting mode that does not use the dynamic range expansion unit;
A flash means for illuminating the subject,
The photographing mode selection means, when the flash unit used, the normal shooting mode and the second feature and to Lud digital camera to select one of the dynamic range widening photography mode using the dynamic range expansion means. A backlight determining unit configured to determine whether or not the subject is in a backlight state, and the shooting mode selection unit is configured to dynamically use the second dynamic range expansion unit when it is determined that the backlight is not backlit when the flash unit is used; 6. The digital camera according to claim 5 , wherein a range expansion photographing mode is selected. First dynamic range expansion means for generating a single captured image by combining a plurality of captured images obtained with different exposure amounts for the same subject, and second dynamic range expansion for performing gradation conversion processing on the captured image Dynamic range expansion means having at least two expansion means of the means;
A shooting mode selection unit that selects either a dynamic range expansion shooting mode for performing shooting using the dynamic range expansion unit and a normal shooting mode that does not use the dynamic range expansion unit;
A flash means for illuminating the subject,
The photographing mode selection means, when selecting the dynamic range widening photography mode when the flash unit used, and characterized by selecting a mode using the second dynamic range expansion means as the dynamic range expansion means Lud digital camera.

Images