JP2006325067A - Imaging apparatus and control method of imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high quality image of optimum exposure even when an object and composition are changed during consecutive photographing in a consecutive photographing mode in an imaging apparatus. <P>SOLUTION: A change in composition is detected, when the composition is the same as that of the previous photographing mode, exposure at photographing is corrected on the basis of image data photographed in the same composition, and when the composition is changed, exposure is not corrected. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an imaging apparatus and an imaging apparatus control method. More specifically, the present invention relates to an image pickup apparatus and an image pickup apparatus control method that detect exposure and correct exposure.

  In order to make it possible to reproduce an image closer to the actual subject in an imaging device such as a digital camera, the density distribution information of the live view image is analyzed, or the luminance distribution information of the subject obtained from a photometric sensor with multiple photometric areas From this it is known to set the exposure. However, since the dynamic range of the image sensor is narrower than that of a silver salt film, it is difficult to obtain an appropriate exposure when the luminance distribution of the subject is wide, such as during backlighting or flash photography.

  As a method of analyzing the captured image based on the luminance distribution of the subject and correcting exposure, the first captured image data is analyzed in auto bracket shooting in which the shooting conditions such as exposure are changed little by little. In accordance with the image data distribution obtained from the above, a method of taking an image by obtaining an exposure correction amount at the time of photographing for the second and subsequent images has been proposed (for example, see Patent Document 1).

Also, in a camera capable of split metering, when the main subject's tentative composition is determined and then the composition is changed to the desired composition, metering is performed to detect where the main subject has moved on the shooting screen. There has been proposed a method of exposing with emphasis on the photometric value of the main subject after movement. (For example, refer to Patent Document 2).
JP 2004-245923 A Japanese Patent Laid-Open No. 11-64920

  Cameras that do not perform live view, such as single-lens reflex digital cameras, use the metering sensor to set the exposure of the image sensor, so it may not be possible to shoot with optimal exposure due to the difference in photometry range and sensitivity with the image sensor. It was. Furthermore, when shooting continuously in continuous shooting mode, the photographer cannot reproduce and check the captured images during continuous shooting, so the photographer is not aware that the exposure is inappropriate until the end of shooting, and is useless. There was a problem of taking pictures.

  However, the method disclosed in Patent Document 1 is applied to auto bracket shooting in which the same subject is shot with the same composition while gradually changing shooting conditions such as exposure, and is used for shooting in single frame shooting mode or continuous shooting mode. Is not applicable. In particular, when the subject or the composition changes at the time of shooting, it is necessary to change the exposure correction amount according to the subject or the composition, so the technique described in Patent Document 1 cannot be applied.

  Also, the method of Patent Document 2 is applied when the same subject is photographed with a slightly different composition, and cannot be applied when the subject is changed or the composition is greatly changed.

  The present invention has been made in view of the above problems, and is an imaging device that detects a change in composition and corrects an exposure value based on image data captured with the same composition to obtain a high-quality image with optimum exposure. It is another object of the present invention to provide a method for controlling an imaging apparatus.

  The object of the present invention can be achieved by the following constitution.

(Claim 1)
A metering means for metering the brightness of the subject;
Exposure setting means for setting an exposure value based on photometric data of the photometric means;
An image sensor that photoelectrically converts a subject image incident from a lens barrel;
In an imaging apparatus having
Exposure correction amount calculating means for calculating an exposure correction amount for correcting the exposure value based on image data photographed at the exposure value;
Composition change detection means for detecting that the composition has been changed since the image data was shot;
An image pickup apparatus comprising: a control unit that corrects the exposure correction amount at the time of shooting according to a composition change detection result detected by the composition change detection unit.

(Claim 2)
When the composition change detecting unit detects a change in the composition, the exposure value is corrected without correcting the exposure correction amount, and the exposure correction amount calculating unit calculates the exposure correction amount based on the captured image data. The imaging device according to claim 1, wherein the imaging device is calculated.

(Claim 3)
The imaging device has angular velocity detection means for detecting an angular velocity at which the imaging device moves,
The imaging apparatus according to claim 1, wherein the composition change detection unit detects a composition change based on an angular velocity detected by the angular velocity detection unit.

(Claim 4)
The imaging apparatus has a distance measuring means for measuring a distance to a subject,
The imaging apparatus according to claim 1, wherein the composition change detection unit detects a composition change based on distance information measured by the distance measuring unit.

(Claim 5)
5. The imaging apparatus according to claim 1, wherein the composition change detection unit detects a composition change based on a photometric value measured by the photometry unit. 6.

(Claim 6)
An exposure setting step for setting an exposure value based on the photometric data of the photometric means;
An exposure correction amount calculating step of calculating an exposure correction amount for correcting the exposure value based on image data photographed at the exposure value;
A composition change detection process for detecting that the composition has been changed since the last shooting;
A control method for an imaging apparatus, wherein the exposure correction amount is corrected at the time of shooting in accordance with a detection result of the composition change detected in the composition change detection step.

According to the first or sixth aspect of the invention, the exposure correction amount calculated from the image data at the time of the previous shooting is corrected at the time of shooting according to the detection result of the composition change. An image pickup apparatus that can obtain a high-quality image with more appropriate exposure from the second frame can be provided when shooting.
.

  According to the second aspect of the present invention, when it is detected that the composition has been changed since the last shooting, the exposure is not performed and the exposure correction amount is calculated from the captured image data. An imaging device capable of obtaining a high-quality image with more appropriate exposure can be provided from the subsequent second frame.

  According to the third aspect of the present invention, since the change of the composition is detected by the angular velocity detection means, it is possible to provide an imaging apparatus that can detect the change of the composition reliably and obtain a high-quality image with proper exposure.

  According to the fourth aspect of the invention, since the change of the composition is detected from the distance measurement information, it is possible to provide an imaging apparatus that can detect the change of the composition reliably and obtain a high-quality image with appropriate exposure.

  According to the fifth aspect of the present invention, since the change of the composition is detected from the photometric information, it is possible to provide an imaging apparatus that can detect the change of the composition reliably and obtain a high-quality image with appropriate exposure.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is an external rear view showing a schematic configuration of a digital camera 1 which is an embodiment to which an imaging apparatus according to the present invention is applied.

  A shutter button 61 and a shooting mode dial 64 are provided on the upper surface side of the camera body 2. On the back side of the camera body 2, a power switch 102, a liquid crystal monitor 81, a mode switch 62, a display switching button 63, a cross key 65, an execution button 66, a viewfinder 104, a viewfinder eyepiece 105, and a memory card lid 82 are provided. ing.

  The mode switch 62 is a switch for switching between a photographing mode, a reproduction mode, and a setup mode. The shooting mode is a mode for taking a picture, and the playback mode is a mode for playing back and displaying the shot image recorded on the memory card 25 on the liquid crystal monitor 81. The setup mode is a mode for performing various settings. In the setup mode, the recording mode is a mode in which a captured image to be recorded in the memory card 25 is compressed and recorded after image processing, a mode in which the captured image is recorded without being subjected to image processing and uncompressed, a compressed image after image processing, Either a mode for recording both uncompressed images without image processing can be set. Various settings in the setup mode are set with the cross key 65 and the execution button 66 while viewing the setting screen displayed on the liquid crystal monitor 81 after selecting the setup mode.

  The shooting mode dial 64 is a dial for switching the shooting mode. The shooting mode can be selected from a single frame shooting mode, a continuous shooting mode in which continuous shooting is performed, and a bracket shooting mode in which continuous shooting is performed by changing shooting conditions. The number of images to be continuously shot in the continuous shooting mode is set with the cross key 65 and the execution button 66 while viewing the setting screen displayed on the liquid crystal monitor 81. In the bracket shooting mode, the AE bracket shooting mode in which multiple exposures are taken by changing the exposure little by little, the aperture bracket shooting mode in which the exposure is constant and the combination of the aperture and shutter speed is changed, and the speed bracket shooting mode are the same. This can be set with the cross key 65 and the execution button 66.

  The internal configuration of the digital camera 1 shown in FIG. 1 will be described with reference to FIG. 2A and 2B are cross-sectional views as seen from the side of the digital camera 1 in FIG. FIG. 2A shows a state before photographing, and FIG. 2B shows a state during photographing.

  The digital camera 1 is a so-called digital single-lens reflex camera with interchangeable lenses, and mainly includes a camera main body 2 and a photographing lens 3 coupled to the camera main body 2.

  The photographic lens 3 mainly includes a lens barrel 31, a plurality of lens groups 32 provided in the lens barrel 31, a diaphragm 33, and the like. Most of the light incident along the optical axis L of the plurality of lens groups 32 is bent 90 degrees perpendicularly to the upper direction (upward in the drawing) by the first mirror 34 a and forms an image on the focusing screen 38. The formed optical image is reflected twice inside the pentaprism 35, and the photographer views the subject image through the eyepiece 104. The photometric sensor 41, which is the photometric means of the present invention provided on the upper part of the pentaprism 35, measures the subject image formed on the focusing screen 38 and obtains information on the luminance distribution of the subject to perform automatic exposure. Is provided.

  On the other hand, part of the light incident along the optical axis L of the plurality of lens groups 32 is transmitted through the first mirror 34a, which is a semi-transmissive mirror, and is incident on the second mirror 34b. The incident light is bent 90 degrees perpendicular to the lower direction (downward direction in the drawing) by the second mirror 34b, enters the AF sensor optical unit 36 as an optical axis L2, and forms an image on the distance measuring sensor 42.

  The angular velocity sensor 45 is an angular velocity detection means of the present invention. The angular velocity sensor 45 has a function of detecting angular velocities in the yaw direction and pitch direction illustrated in FIG. 2C and outputs a voltage corresponding to the detected angular velocity. As will be described later, the main microcomputer unit 7 converts the output voltage of the angular velocity sensor 45 into a digital value to obtain an angular velocity.

  Next, a state during photographing will be described with reference to FIG.

  During shooting, the first mirror 34a and the second mirror 34b are retracted from the optical axis L1 by a mirror driving mechanism (not shown) and stored in the upper part of the camera body 2. FIG. 2A shows a state in which the shutter 51 is completely closed so as to block the optical path before photographing. When exposure is performed during shooting, the shutter 51 opens up and down as shown in FIG. 2B to open the optical path.

  In this state, light incident from the plurality of lens groups 32 forms an image on a CCD (charge coupled device) 5 which is an example of an image sensor. In the present invention, the image sensor may be a solid-state image sensor such as a CMOS sensor or a CID sensor instead of the CCD. The video signal acquired by the CCD 5 is converted into a digital signal by a circuit board (not shown), subjected to image processing, and then recorded on the memory card 25.

  2A shows a state in which the flash 94 is housed inside the camera body 2, and FIG. 2B shows a state in which the light emitting portion is projected from the camera body 2 and can emit light toward the subject. Show.

  At the time of flash photography, prior to flash photography, the flash 94 is preliminarily emitted, the reflected light from the subject is measured, and the light quantity at the main emission is set.

  When the flash 94 emits light with a predetermined light amount while the shutter 51 is still closed, the reflected light reflected by the subject enters through the plurality of lens groups 32 and is reflected by the surface of the shutter 51, and the flash light amount photometric sensor. 43 is formed so as to form an image.

  The photographing lens 3 is configured as a zoom lens, and the focal length (imaging magnification) can be changed by changing the arrangement of the lens group 32.

  The CCD 5 is an image sensor composed of fine pixel groups each provided with a color filter, and an optical signal (subject image) of a subject formed by the photographing lens 3 is converted into an image signal having, for example, RGB color components. To photoelectric conversion. The light receiving surface of the CCD 5 is disposed so as to coincide with the imaging plane, and a partial area of the imaging plane including the image circle is acquired as image data (also simply referred to as “image” as appropriate in this specification). The Rukoto.

  FIG. 3 is a block diagram showing a main functional configuration of the digital camera 1 of FIGS. 1 and 2. The same components as those shown in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof is omitted.

  The digital camera 1 includes an A / D conversion unit 21, an image processing unit 22, an operation unit 60, a main microcomputer unit 7, a buffer memory 26, an image memory 23, a memory card 25, and the like.

  The main microcomputer 7 that functions as a control means is configured to include a microcomputer. That is, the main microcomputer unit 7 includes a CPU 70 that performs various arithmetic processing, a RAM 75 that is a work area for performing arithmetic, and a ROM 76 that stores a control program and the like, and performs operations of the respective processing units of the digital camera 1. Control all over. As the ROM 76 which is a non-volatile memory, for example, an EEPROM capable of electrically rewriting data is adopted. As a result, the ROM 76 can rewrite data and retains the contents of the data even when the power is turned off.

  The outputs of the shutter button 61, the mode switch 62, the display switching button 63, the shooting mode dial 64, the cross key 65, the execution button 66 and the power switch 102, which are a plurality of operation members provided independently of the operation unit 60, are the main microcomputer. It is input to part 7.

  An operator (user) can perform various setting operations by performing predetermined operations on the operation unit 60.

  For example, the operator can switch the mode of the digital camera 1 between the playback mode and the shooting mode by operating the mode switch 62. The power switch 102 can also be used to turn on / off the power.

  The shooting mode dial 64 is a dial for switching between a single frame shooting mode, a continuous shooting mode, and a bracket shooting mode.

  A switch that is turned on when the shutter button 61 is half-pressed (S1) and a switch that is turned on when the shutter button 61 is fully pressed (S2) are linked to each other, so that the CPU 70 can detect the timing of S1 and S2.

  In single-frame shooting mode, the shutter button 61 is fully pressed (S2), and one frame is shot. In continuous shooting mode, the shutter button 61 is fully pressed (S2). In this mode, shooting is performed.

  The bracket shooting mode automatically shoots by shifting the exposure amount gradually from the standard exposure conditions. The AE bracket shooting mode and exposure amount are constant, and priority is given to either the aperture or shutter speed, and the shooting is shifted gradually. There are aperture bracket shooting mode and speed bracket shooting mode.

  The mirror driving unit 91 drives the mirror 34 according to a command from the main microcomputer unit 7 and retracts it from the optical path of the photographing lens 3. The shutter driving unit 93 opens the shutter 51 in response to a command from the main microcomputer unit 7.

  The A / D conversion unit 21, the buffer memory 26, the image processing unit 22, and the image memory 23 are processing units that handle images acquired by the CCD 5.

  The analog signal image acquired by the CCD 5 is sequentially converted into, for example, a 14-bit digital signal by the A / D converter 21 and temporarily stored in the buffer memory 26 as digital image data. The image data is called raw data before image processing, that is, RAW data. In the continuous shooting mode and the bracket mode, the set predetermined number of RAW data is temporarily stored in the buffer memory 26.

  The image processing unit 22 has image processing functions such as WB (White Balance) correction, pixel interpolation, linear matrix, gamma correction, color difference matrix processing, contour correction, and image compression. The set values of the correction amounts for gamma correction, contour correction, and WB correction are set by commands from the main microcomputer unit 7.

  The WB correction is a function for adjusting the white balance by multiplying the coefficient set by the image processing unit 22 with the R and B image data of the RAW data obtained from the CCD 5, respectively.

  The linear matrix is a function that separates pixel data for each of R, G, and B after white balance adjustment, and performs pixel interpolation to generate frame sequential R, G, and B image data.

  The color difference matrix processing is a function of correcting the color error due to the spectral sensitivity by adding a coefficient corresponding to the spectral sensitivity by 3 × 3 matrix calculation to the R, G, B image data.

  The image processing unit 22 has a look-up table that represents gradation characteristics as input / output characteristics, and has a gamma correction function that converts and outputs a digital value corresponding to the input digital value. In other words, the R, G, B image data is subjected to gradation conversion with gradation characteristics set by the image processing unit 22 in the lookup table.

  The color difference matrix processing is a function that performs 3 × 3 matrix operation on the R, G, and B image data subjected to gradation conversion, and converts them into luminance Y, color difference Cr, and Cb signals. The contour correction is a function for correcting the contour of luminance Y.

  Image compression is a function for compressing image data after image processing into JPEG format or the like.

The distance measuring sensor 42 is used for automatic focusing control, and the photometric sensor 41 and the flash light quantity measuring sensor 43 are used for automatic exposure control. The angular velocity sensor 45 is a sensor used for detection of the rotation angle of the digital camera 1 and camera shake correction control.
The main microcomputer unit 7 includes an A / D converter (not shown) that converts the input output voltage of each sensor into a digital value and inputs the digital value to the main microcomputer unit 7.

  The main microcomputer unit 7 includes an automatic focusing control unit (hereinafter referred to as AF control unit) 71 which is a distance measuring unit of the present invention, and an automatic exposure control unit (hereinafter referred to as AE control unit) which is an exposure setting unit of the present invention. ) 72, a camera shake control unit 74, a composition change detection unit 75 which is a composition change detection unit of the present invention, and an exposure correction amount calculation unit 76 which is an exposure correction amount calculation unit of the present invention. Various functions of the main microcomputer unit 7 are realized by the CPU 70 performing arithmetic processing in accordance with a control program stored in the ROM 76 in advance.

  In addition, it has a control function for recording the compressed image in the memory card 25 and displaying it on the LCD 81 or the like. Various processes for such an image are also performed based on the control of the main microcomputer unit 7.

  The AF control unit 71 obtains an in-focus evaluation value from the luminance information obtained from the distance measuring sensor 42 and adjusts the focal position of the photographing lens 3 to realize automatic focusing control. Further, distance information from the focal position of the photographic lens 3 after adjustment to the subject can be obtained.

  The AE control unit 72 obtains an exposure value from the photometric value of the subject luminance obtained from the photometric sensor 41 which is a photometric unit of the present invention, and controls the shutter driving unit 93 and the aperture driving unit 331 to control a predetermined shutter speed and aperture. Automatic exposure control is realized by adjusting the value.

  The camera shake controller 74 obtains information on the angular velocity from the angular velocity sensor 45, calculates the amount of blur on the imaging surface (not shown) of the lens unit 32, and moves the CCD 5 in a direction to cancel out the amount of blur using an imaging element driving means (not shown). Let

  3 includes a zoom / focus drive unit 332 and an aperture drive unit 331. The zoom / focus drive unit 332 appropriately drives the lenses included in the lens group 32 in the optical axis direction so that the focal length is set by the user and is in focus (focusing).

  The aperture driving unit 331 adjusts the aperture diameter of the aperture 33 so that the aperture value set by the AE control unit 72 is obtained. The zoom / focus drive unit 332 and the aperture drive unit 331 are also electrically connected to the main microcomputer unit 7 and operate under the control of the main microcomputer unit 7.

  Similarly, in the case of shooting with flash light, the AE control unit 72 calculates the exposure value based on the representative luminance value of the photometry block obtained by the flash light quantity photometry sensor 43, and controls the light emission amount of the flash 94. Automatic exposure control.

  As an example, the composition change detection unit 75 determines that the shooting direction has changed from the change in the angular velocity of the digital camera 1 that is detected by the angular velocity sensor 45, and detects the change in the composition. The composition change detection algorithm will be described in detail later.

  The exposure correction amount calculation unit 76 analyzes the image data captured with the exposure value calculated by the AE control unit 72, and calculates an exposure correction amount for correcting the exposure value from the result. The algorithm for calculating the exposure correction amount will be described in detail later.

  FIG. 4 is a flowchart for explaining a schematic procedure at the time of shooting performed by the imaging apparatus according to the first embodiment of the present invention. In FIG. 4, the processing after the digital camera 1 is turned on, the continuous shooting mode is selected as the shooting mode, and the shooting standby state is entered will be described.

  When the shutter button 61 is half-pressed (S1) (step S101), the AF control unit 71 performs automatic focus control according to the output of the distance measuring sensor. Information on the distance X1 to the subject is recorded in the RAM 75 after the focus adjustment (step S102).

  The AE control unit 72 obtains the exposure value EV1 (EV) from the photometric value B1 output from the photometric sensor 41, and records the photometric value B1 and the exposure value EV1 (EV) in the RAM 75 (step S103).

  Next, it is determined whether or not the shutter button 61 is fully pressed (SW2 ON) (step S104). When the shutter button 61 is not fully depressed (S2) (step S109; No), the process returns to step S102, and automatic focus control is performed again. When the shutter button 61 is fully pressed (S2) (step S109; Yes), the main microcomputer unit 7 starts a shooting sequence, sends a command to the mirror driving unit 91 at a predetermined timing, and moves the mirror 34 to the shooting lens 3. Retreat from the optical path (step S105).

  Next, the main microcomputer unit 7 initializes the rotation angle θx in the yaw direction and the rotation angle θy in the pitch direction of the digital camera 1 recorded in the RAM 75 to zero. Integration of the voltage according to the angular velocity output from the angular velocity sensor 45 is started, and the obtained voltage is recorded in the RAM 75 as rotation angles θx and θy at predetermined time intervals (step S106). More specifically, the integral value of the voltage according to the angular velocity in the yaw direction of the angular velocity sensor 45 is the rotation angle θx in the yaw direction, and the integral value of the voltage according to the angular velocity in the pitch direction of the angular velocity sensor 45 is the rotation angle θy in the pitch direction. Recorded in the RAM 75. θx and θy are angles at which the digital camera 1 has rotated in the yaw direction and the pitch direction, respectively, from the time of step S106.

  The AE control unit 72 obtains a combination of the aperture value and the shutter speed from the exposure value EV1 (EV) recorded in the RAM 75, and instructs the aperture drive unit 331 to set the aperture 33 to the aperture value (step S107). During the exposure time determined by the shutter speed obtained in step S107, the AE control unit 72 instructs the shutter drive unit 93 to open the shutter 51 and expose the CCD 5. When a predetermined exposure time has elapsed, the AE control unit 71 sends a command to the shutter drive unit 93 to close the shutter 51. The main microcomputer unit 7 temporarily stores the image data read from the CCD 5 together with the frame number in the buffer memory 26 (step S108). The main microcomputer unit 7 sends a command to the mirror drive unit 91 at a predetermined timing to return the mirror 34 to a predetermined position (step S109).

Next, the exposure correction amount calculation unit 76 counts the number of pixels having the same numerical data from the image data of one frame most recently temporarily stored in the buffer memory 26 in step S108. (Step S110)
FIG. 7 is a graph showing the results counted in step S110. Here, it is assumed that each pixel has numerical data of 14 bits, that is, a maximum of 16384. FIG. 7A shows an example of the numerical data distribution obtained in the case of underexposure, and FIG. RX is an appropriate exposure level. If the average value of all the pixels is RX, the exposure is appropriate. In the case of FIG. 7A, the average value of all the pixels is A1, which is a value lower than the appropriate exposure level RX. Similarly, the average value of all the pixels in the case of FIG. 7B is A2, which is higher than the appropriate exposure level RX.

  Here, all pixels of the image data are counted, but a specific area may be counted, the area may be divided and weighted, or thinned out at an appropriate interval.

  Next, the exposure correction amount calculation unit 76 calculates the exposure correction amount ΔEV according to the numerical data distribution of the image data captured most recently obtained in step S110, and stores it in the RAM 45 (step S111). The exposure correction amount ΔEV is obtained by, for example, equation (1). However, A is the average value of the numerical data of the most recently imaged frames, and RX is the appropriate exposure level.

ΔEV = Log (A / RX) (1)
In Expression (1), the exposure correction amount ΔEV is obtained from the average level of all the pixels. Alternatively, for example, paying attention to the number of pixels in the dark portion and the highlight portion, if any of them is a predetermined number or more, the pixel The exposure correction amount can also be obtained according to the number of. Taking the case of FIG. 7A as an example, the exposure correction amount calculator 76 counts the number of pixels of the numerical data 0, and calculates the exposure correction amount ΔEV from the table set in the ROM 76. In the case of FIG. 7A, since the exposure is insufficient, an exposure correction amount ΔEV that gives more exposure is calculated.

  Next, the main microcomputer unit 7 determines whether or not the shutter button 61 is fully pressed (SW2 ON) (step S112). When the shutter button 61 is fully pressed (S2) (step S112; Yes), the main microcomputer unit 7 performs automatic focus control according to the output of the distance measuring sensor 42. Information about the distance X2 to the subject is recorded in the RAM 75 after the focus adjustment (step S115).

  The AE control unit 72 obtains the exposure value EV2 (EV) from the photometric value B2 output from the photometric sensor 41, and records the exposure value EV2 (EV) in the RAM 75 (step S116).

  The composition change detection unit 75 calculates the rotation angle θ, which is the vector sum of the rotation angles in the yaw direction and the pitch direction, from the square root of the square sum of θx and θy stored in the RAM 75 (step S117), and sets the threshold δ. It is determined whether or not it exceeds (step S118). The rotation angle θ obtained in step S117 is the angle that the digital camera 1 has rotated since the previous frame was shot. If the rotation angle θ exceeds the threshold δ, it is determined that the composition has been changed.

  If the rotation angle θ does not exceed the threshold δ (step S118; No), it is determined that the image is shot with the same composition, and the process proceeds to step S119. The main microcomputer unit 7 sends a command to the mirror drive unit 91 to retract the mirror 34 from the optical path of the photographic lens 3 (step S119).

  The AE control unit 71 adds the exposure correction amount ΔEV calculated by the main microcomputer unit 7 in step S111 to the exposure value EV2 obtained in step S116 to obtain an exposure value (step S120).

  Next, as in step S106, the main microcomputer unit 7 initializes the yaw direction rotation angle θx and the pitch direction rotation angle θy of the digital camera 1 recorded in the RAM 75 to zero. Integration of the voltage according to the angular velocity output from the angular velocity sensor 45 is started, and the obtained voltage is recorded in the RAM 75 as rotation angles θx and θy at predetermined time intervals (step S121).

  The AE control unit 71 exposes the CCD 5 with the exposure value obtained in step S120, and the main microcomputer unit 7 temporarily stores the image data read from the CCD 5 together with the frame number in the buffer memory 26 after the exposure is completed (step S122). .

  Next, proceeding to step S123, the main microcomputer unit 7 sends a command to the mirror drive unit 91, returns the mirror 34 to a predetermined state, and returns to step S112 (step S123).

  When the rotation angle θ exceeds the threshold δ (step S118; Yes), it is determined that the composition has been changed, and the process proceeds to step S124. The main microcomputer unit 7 sends a command to the mirror driving unit 91 to retract the mirror 34 from the optical path of the photographic lens 3 (step S124). The AE control unit 71 sets the exposure value EV2 obtained in step S116 as the exposure value (step S125).

  Next, as in step S106, the main microcomputer unit 7 initializes the yaw direction rotation angle θx and the pitch direction rotation angle θy of the digital camera 1 recorded in the RAM 75 to zero. Integration of the voltage according to the angular velocity output from the angular velocity sensor 45 is started, and the obtained voltage is recorded in the RAM 75 as rotation angles θx and θy at predetermined time intervals (step S126).

  The AE control unit 71 exposes the CCD 5 with the exposure value obtained in step S120, and the main microcomputer unit 7 temporarily stores the image data read from the CCD 5 together with the frame number in the buffer memory 26 after the exposure is completed (step S127). .

  Proceeding to step S128, the main microcomputer section 7 sends a command to the mirror driving section 91 to return the mirror 34 to a predetermined state, and returns to step S110 (step S128).

  Returning to the description of step S112. When the shutter button 61 is not fully pressed (SW2 ON) (step S112; No), the main microcomputer unit 7 proceeds to step S113, and the image processing unit 22 performs pixel interpolation on the image data temporarily stored in the buffer memory 26. Image processing such as matrix processing, WB correction, gamma correction, and contour correction is performed (step S113). Next, the image processing unit 22 compresses the image data that has undergone image processing in step S <b> 113, and temporarily stores the compressed image data in the image memory 23. Thereafter, the main microcomputer unit 7 sequentially records the image data on the memory card 25 (step S130). This is the end of shooting.

  A second embodiment of the present invention will be described with reference to a flowchart for explaining a schematic procedure at the time of photographing performed by the imaging apparatus of FIG. The second embodiment is an example in which composition change detection is obtained from the distance to the subject. Also in FIG. 5, the processing after the digital camera 1 is turned on, the continuous shooting mode is selected as the shooting mode, and the shooting standby state is set will be described.

  The processing from step S101 to step S111 until the first frame is imaged is the same as in FIG. 4 except that the processing of step 106 is not performed. The case of Yes will be described. In the following description, the same processes as those in FIG. 4 are denoted by the same reference numerals, and the description is simplified.

  The main microcomputer unit 7 determines whether or not the shutter button 61 is fully pressed (SW2 ON) (step S112). When the shutter button 61 is fully pressed (S2) (step S112; Yes), the main microcomputer unit 7 performs automatic focus control according to the output of the distance measuring sensor 42. Information about the distance X2 to the subject is recorded in the RAM 75 after the focus adjustment (step S115).

  The AE control unit 72 obtains the exposure value EV2 (EV) from the photometric value B2 output from the photometric sensor 41, and records the photometric value B2 and the exposure value EV2 (EV) in the RAM 75 (step S116).

  The composition change detection unit 75 calculates a change TX = X1-X2 in the distance to the subject (step S201), and determines whether or not a predetermined threshold ΔX is exceeded (step S202). Here, as an example, if the change TX of the distance to the subject exceeds the threshold value ΔX, it is determined that the composition has been changed.

  If the distance X to the subject does not exceed the threshold value ΔX (step S202; No), it is determined that shooting is performed with the same composition, and the process proceeds to step S119. The main microcomputer unit 7 sends a command to the mirror drive unit 91 to retract the mirror 34 from the optical path of the photographic lens 3 (step S119).

  The AE control unit 71 adds the exposure correction amount ΔEV calculated by the main microcomputer unit 7 in step S111 to the exposure value EV2 obtained in step S116 to obtain an exposure value (step S120).

  Next, the distance to the subject X1 is updated to X2 and recorded in the RAM 75 (step S221).

  The AE control unit 71 exposes the CCD 5 with the exposure value obtained in step S120, and the main microcomputer unit 7 temporarily stores the image data read from the CCD 5 together with the frame number in the buffer memory 26 after the exposure is completed (step S122). .

  Proceeding to step S123, the main microcomputer unit 7 sends a command to the mirror drive unit 91 to return the mirror 34 to a predetermined state, and returns to step S112 (step S123).

  When the change TX of the distance to the subject exceeds the threshold value ΔX (step S202; Yes), it is determined that the composition has been changed, and the process proceeds to step S124. The main microcomputer unit 7 sends a command to the mirror driving unit 91 to retract the mirror 34 from the optical path of the photographic lens 3 (step S124).

  The AE control unit 71 sets the exposure value EV2 obtained in step S116 as the exposure value (step S125).

  Next, the distance to the subject X1 is updated to X2 and recorded in the RAM 75 (step S226).

  The AE control unit 71 exposes the CCD 5 with the exposure value obtained in step S120, and the main microcomputer unit 7 temporarily stores the image data read from the CCD 5 together with the frame number in the buffer memory 26 after the exposure is completed (step S127). . Next, the main microcomputer unit 7 sends a command to the mirror drive unit 91 to return the mirror 34 to a predetermined state, and returns to step S110 (step S128).

  If step S112 is No, the process is the same as that in FIG. 4, and image data is recorded in step S114, and shooting is completed.

  A third embodiment of the present invention will be described with reference to a flowchart for explaining a schematic procedure at the time of photographing performed by the imaging apparatus of FIG. The third embodiment is an example in which composition change detection is obtained from a photometric value. Also in FIG. 5, the processing after the digital camera 1 is turned on, the continuous shooting mode is selected as the shooting mode, and the shooting standby state is set will be described.

  The processing from step S101 to step S111 until the first frame is imaged is the same as in FIG. 4 except that the processing of step 106 is not performed. The case of Yes will be described. In the following description, the same processes as those in FIG.

  The main microcomputer unit 7 determines whether or not the shutter button 61 is fully pressed (SW2 ON) (step S112). When the shutter button 61 is fully pressed (S2) (step S112; Yes), the main microcomputer unit 7 performs automatic focus control according to the output of the distance measuring sensor 42. Information about the distance X2 to the subject is recorded in the RAM 75 after the focus adjustment (step S115).

  The AE control unit 72 obtains the exposure value EV2 (EV) from the photometric value B2 output from the photometric sensor 41, and records the photometric value B2 and the exposure value EV2 (EV) in the RAM 75 (step S116).

  The composition change detection unit 75 calculates a photometric value change TB = B1−B2 (step S301), and determines whether or not a predetermined threshold ΔB is exceeded (step S302). Here, as an example, when the photometric value change TB exceeds the threshold value ΔB, it is determined that the composition has been changed.

  When the photometric value B does not exceed the threshold ΔB (step S302; No), it is determined that the same composition is being shot, and the process proceeds to step S119. The main microcomputer unit 7 sends a command to the mirror drive unit 91 to retract the mirror 34 from the optical path of the photographic lens 3 (step S119).

  The AE control unit 71 adds the exposure correction amount ΔEV calculated by the main microcomputer unit 7 in step S111 to the exposure value EV2 obtained in step S116 to obtain an exposure value (step S120). Next, the brightness B1 = B2 is updated and recorded in the RAM 75 (step S221).

  The AE control unit 71 exposes the CCD 5 with the exposure value obtained in step S120, and the main microcomputer unit 7 temporarily stores the image data read from the CCD 5 together with the frame number in the buffer memory 26 after the exposure is completed (step S122). .

  Proceeding to step S123, the main microcomputer unit 7 sends a command to the mirror drive unit 91 to return the mirror 34 to a predetermined state, and returns to step S112 (step S123).

  If the photometric value change TB exceeds the threshold ΔB (step S302; Yes), it is determined that the composition has been changed, and the process proceeds to step S124. The main microcomputer unit 7 sends a command to the mirror driving unit 91 to retract the mirror 34 from the optical path of the photographic lens 3 (step S124).

  The AE control unit 71 sets the exposure value EV2 obtained in step S116 as the exposure value (step S125).

  Next, the brightness B1 = B2 is updated and recorded in the RAM 75 (step S326).

  The AE control unit 71 exposes the CCD 5 with the exposure value obtained in step S120, and the main microcomputer unit 7 temporarily stores the image data read from the CCD 5 together with the frame number in the buffer memory 26 after the exposure is completed (step S127). . Proceeding to step S128, the main microcomputer section 7 sends a command to the mirror driving section 91 to return the mirror 34 to a predetermined state, and returns to step S110 (step S128).

  If step S112 is No, the process is the same as that in FIG. 4, and image data is recorded in step S114, and shooting is completed.

  As described above, according to the present embodiment, a change in composition is detected, and exposure correction at the time of shooting is performed based on image data previously shot with the same composition. It is possible to provide an imaging device capable of obtaining a high-quality image that can be photographed with an optimal exposure even when the temperature changes.

  In addition, if such an imaging apparatus is used, a high-quality digital camera can be provided.

  In addition, although the digital single-lens reflex camera was illustrated as this Embodiment, it is applicable also to digital cameras other than a single-lens reflex system, a mobile phone with a camera, etc. In the present embodiment, the composition change detection is detected based on the single information of the angular velocity, the distance information, and the photometric value at which the imaging apparatus moves. However, the composition detection may be performed from a plurality of pieces of information.

1 is an external view of a digital camera 1 according to the present invention. It is sectional drawing which shows the structure of the digital camera 1 which concerns on this invention. 1 is a functional block diagram of a digital camera 1 according to the present invention. It is a flowchart explaining the 1st Embodiment of this invention. It is a flowchart explaining the 2nd Embodiment of this invention. It is a flowchart explaining the 3rd Embodiment of this invention. It is explanatory drawing explaining the example of distribution of the numerical data obtained from the image | photographed image data.

Explanation of symbols

1 Digital Camera 2 Camera Body 3 Shooting Lens 5 CCD
22 Image processing unit 41 Photometric sensor 42 Distance sensor 45 Angular velocity sensor 70 CPU
73 WB control unit 75 Composition change detection unit 76 Exposure correction amount calculation unit L Optical axis of the taking lens

Claims (6)

A metering means for metering the brightness of the subject;
Exposure setting means for setting an exposure value based on photometric data of the photometric means;
An image sensor that photoelectrically converts a subject image incident from a lens barrel;
In an imaging apparatus having
Exposure correction amount calculating means for calculating an exposure correction amount for correcting the exposure value based on image data photographed with the exposure value;
Composition change detection means for detecting that the composition has been changed since the image data was shot;
An image pickup apparatus comprising: a control unit that corrects the exposure correction amount at the time of shooting according to a composition change detection result detected by the composition change detection unit. When the composition change detecting unit detects a change in the composition, the exposure value is corrected without correcting the exposure correction amount, and the exposure correction amount calculating unit calculates the exposure correction amount based on the captured image data. The imaging device according to claim 1, wherein the imaging device is calculated. The imaging device has angular velocity detection means for detecting an angular velocity at which the imaging device moves,
The imaging apparatus according to claim 1, wherein the composition change detection unit detects a composition change based on an angular velocity detected by the angular velocity detection unit. The imaging apparatus has a distance measuring means for measuring a distance to a subject,
The imaging apparatus according to claim 1, wherein the composition change detection unit detects a composition change based on distance information measured by the distance measuring unit. 5. The imaging apparatus according to claim 1, wherein the composition change detection unit detects a composition change based on a photometric value measured by the photometry unit. 6. An exposure setting step for setting an exposure value based on the photometric data of the photometric means;
An exposure correction amount calculating step of calculating an exposure correction amount for correcting the exposure value based on image data photographed at the exposure value;
A composition change detection process for detecting that the composition has been changed since the last shooting;
A control method for an imaging apparatus, wherein the exposure correction amount is corrected at the time of shooting in accordance with a detection result of the composition change detected in the composition change detection step.

Images