JP2007282133A - Image processing apparatus, image processing program and image processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processing apparatus etc. capable of acquiring an image with desired exposure conditions on the basis of a photographed image. <P>SOLUTION: The image processing apparatus is provided with a frame memory 6 for storing a plurality of time division images acquired by executing continuous photographing; a correction level instructor 23b and an exposure correction level setter 31d for gradually correcting a previously defined reference exposure quantity; an image adder 32a for adding the plurality of time division images read from the frame memory 6, to generate an added image having the substantially the same exposure quantity as the corrected exposure quantity; and a TFT panel 10 for displaying the added image generated by the image adding section 32a. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image processing apparatus, an image processing program, and an image processing method for processing a plurality of time-division images obtained by capturing images continuously in time.

  In normal still image shooting, when performing one exposure, only shooting based on one shooting condition can be performed. For example, when exposure correction is performed before shooting, shooting is performed only once with the exposure value obtained by correcting the reference exposure value based on the photometric value. Similarly, for example, when shooting by performing spot metering, shooting is performed only once with an exposure value based on the metering value obtained by spot metering.

  On the other hand, a so-called exposure bracket photography technique is known as a technique for obtaining a plurality of images having different exposure values by a single shutter button operation. However, this exposure bracket shooting is to capture a plurality of images by repeatedly performing the exposure operation for the number of sheets set according to the bracket condition, so it can be said that the image is obtained by one exposure. Absent.

  In the conventional exposure compensation, exposure conditions that can be obtained are set before shooting, and one or more images are shot only under the set exposure conditions. It was.

  However, in such a conventional technique, when the presumed shooting condition is not a condition for obtaining an image to be shot, it is necessary to re-shoot, and there is a high possibility of missing a photo opportunity. .

  In addition, there is also known a technique for adjusting the brightness of image data shot under non-optimal exposure conditions after shooting. Images corrected with such a technique are images shot under optimal exposure conditions during shooting. Compared to the above, the S / N is low and the image quality of the image is deteriorated.

  From such a viewpoint, various techniques have been proposed for exposure correction.

  For example, Japanese Patent Laid-Open No. 2004-48421 discloses that exposure adjustment is performed by adding a number of images that are continuously captured at a constant interval (that is, a single shutter speed) according to the subject brightness. An imaging device that can be used is described.

  Japanese Patent Laid-Open No. 2004-222160 discloses a parameter calculation for determining a backlight scene using a photometric value obtained when the release button is half-pressed, and when it is determined that the scene is a backlight scene, A technique is described in which an exposure correction amount is determined based on a weighted average photometric value, a maximum photometric value, and a target value for the maximum photometric value. Further, the publication describes a technique for obtaining composite image data by performing a synthesis process of relatively high-sensitivity first image data and relatively low-sensitivity second image data. Yes.

  Further, in Japanese Patent Application Laid-Open No. 2005-197886, a main image and a sub-image having a different exposure level are stored in association with each other, and the main image and the sub-image are combined to obtain the number of gradations. A technique for generating a large digital image is described. By using such a technique, a digital image whose exposure adjustment has failed can be relieved and reproduced.

In addition, Japanese Patent Application Laid-Open No. 2006-33578 discloses that a plurality of images obtained by performing short-exposure-time shooting repeatedly and correcting a plurality of images thus obtained are combined to appear. A camera that optimizes the exposure of the camera is described.
JP 2004-48421 A JP 2004-222160 A JP 2005-197886 A JP 2006-33578 A

  However, the technique described in Japanese Patent Application Laid-Open No. 2004-48421 described above continuously captures a plurality of times with a maximum exposure time (1/125 seconds or 1/250 seconds) when the subject is darker than a predetermined value. To do. Accordingly, since the images to be added are only images taken at the same shutter speed, it is difficult to perform exposure correction at a desired exposure level on an arbitrary object only by controlling the number of added images. is there.

  In addition, what is described in Japanese Patent Application Laid-Open No. 2005-197886 described above is intended to be able to relieve a digital image whose exposure adjustment has failed, and thus can cover a wide exposure range. It is necessary to photograph the main image and the sub image so that they can be performed. Therefore, the technique described in the publication is not suitable for performing exposure correction in fine steps, and it has become possible to perform exposure correction at a desired exposure level on an arbitrary object. Absent.

  Furthermore, since the digital camera described in the above-mentioned Japanese Patent Application Laid-Open No. 2004-222160 performs photographing after setting an exposure correction amount before photographing, the exposure amount obtained by the correction is optimal. There is no guarantee that the exposure amount. When the high-sensitivity image data and the low-sensitivity image data are combined by adjusting the gain after shooting, the S / N is reduced.

  In addition, in the above-described Japanese Patent Application Laid-Open No. 2006-33578, it is described that a plurality of images are combined, but a configuration in which desired exposure correction is performed on an arbitrary object. Is not described specifically.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an image processing apparatus, an image processing program, and an image processing method capable of obtaining an image with desired exposure conditions based on an image after shooting. .

  In order to achieve the above object, an image processing apparatus according to a first invention sets a storage means for storing a plurality of time-division images obtained by continuously photographing in time, and a desired exposure amount. Exposure setting means for adding, a plurality of time-division images read from the storage means, and an image addition means for generating an addition image having an exposure amount substantially equal to the exposure amount set by the exposure setting means; and Display means for displaying the added image generated by the image adding means.

  An image processing apparatus according to a second invention is the image processing apparatus according to the first invention, wherein the exposure setting means includes an exposure correction means for correcting a predetermined reference exposure in a stepwise manner. The image addition means adds a plurality of time-division images read from the storage means, and generates an addition image having an exposure amount substantially equal to the exposure amount corrected by the exposure correction means.

  Further, an image processing apparatus according to a third invention is obtained by performing exposure with the reference exposure amount setting means for setting the reference exposure amount and the reference exposure amount in the image processing apparatus according to the second invention. Histogram calculation means for calculating the frequency distribution of the brightness of the subject based on the image, exposure condition calculation means for obtaining the exposure condition of the time-division image based on the frequency distribution, and the time-division image based on the exposure condition Imaging means for photographing the image, and the storage means stores the time-division image photographed by the imaging means.

  An image processing device according to a fourth invention is the image processing device according to the third invention, wherein the exposure condition calculation means is between the brightness of the peak of the frequency distribution and the brightness of the center of the dynamic range of the image. The exposure condition is set so that the exposure amount corresponding to the peak brightness of the frequency distribution can be corrected.

  The image processing apparatus according to a fifth aspect of the invention is the image processing apparatus according to the third aspect of the invention, wherein the exposure condition calculation means has a step width of the exposure amount that can be corrected as the difference in exposure amount from the reference exposure amount increases. The above exposure condition is set so that the

  An image processing apparatus according to a sixth aspect of the present invention is the image processing apparatus according to the third aspect of the present invention, further comprising area specifying means for specifying a partial area in the image, wherein the histogram calculation means is the brightness in the partial area. The exposure condition calculation means calculates the exposure condition of the time-division image based on the brightness frequency distribution in the partial area.

  An image processing apparatus according to a seventh aspect of the invention is the image processing apparatus according to the second aspect of the invention, further comprising area specifying means for specifying a partial area in the image, wherein the image adding means is for exposing the partial area. The added image is generated by adding a plurality of time-division images read from the storage means so that the amount is substantially equal to the exposure amount corrected by the exposure correction means.

  An image processing apparatus according to an eighth invention is the image processing apparatus according to the sixth or seventh invention, wherein the display means displays the pointer indicating the partial area so as to overlap the image. The designation means includes a pointing device that allows the pointer displayed on the display means to be moved to a desired position on the image displayed on the display means.

  An image processing apparatus according to a ninth aspect of the present invention is the image processing apparatus according to the first aspect of the present invention, further comprising a blur correction unit that corrects a mutual blur of the plurality of time-division images, and the image addition unit includes the blur By adding the time-division images whose blur has been corrected by the correcting means, an added image having an exposure amount substantially equal to the exposure amount set by the exposure setting means is generated.

  An image processing program according to a tenth aspect of the invention is a computer-added image having an exposure amount that is substantially equal to an exposure amount that is set as desired by adding a plurality of time-division images obtained by continuously capturing images to a computer. And a step of displaying the generated added image.

  In an image processing method according to an eleventh aspect of the present invention, a plurality of time-division images obtained by continuously shooting in time are added to generate an added image having an exposure amount substantially equal to a desired exposure amount. And a step of displaying the generated added image.

  According to the image processing apparatus, the image processing program, and the image processing method of the present invention, an image with a desired exposure condition can be obtained based on an image after shooting.

  Embodiments of the present invention will be described below with reference to the drawings.

[Embodiment 1]
1 to 13 show Embodiment 1 of the present invention, and FIG. 1 is a block diagram showing a configuration of an imaging apparatus.

  In the first embodiment, the image processing apparatus is applied to an imaging apparatus such as a digital camera.

  That is, as shown in FIG. 1, the imaging apparatus includes a lens 1, an imaging device 2, an imaging circuit 3, an A / D converter 4, a signal processing circuit 5, a frame memory 6, and a FIFO memory 7. An on-screen circuit 8, a TFT liquid crystal driving circuit 9, a TFT panel 10, a backlight unit 11, a video output circuit 12, a video output terminal 13, a recording buffer 14, and a recording medium interface (recording medium I). / F) 15, recording medium 16, actuator 17, actuator drive circuit 18, EEPROM 19, shake detection unit 21, external data interface (external data I / F) 22, key matrix 23, and LCD display A circuit 24, an LCD panel 25, a battery 26, a power supply circuit 27, a backup power supply 28, a battery state detection circuit 29, A CPU 31, is configured to include a first CPU 32, a.

  The lens 1 is for forming an optical subject image on the image sensor 2.

  The imaging element 2 is an imaging unit that photoelectrically converts an optical subject image formed by the lens 1 and outputs an electrical video signal. As long as the image pickup device 2 is of a type that can perform high-speed reading, any one of a CCD, a CMOS, or another type of image pickup device may be used.

  The imaging circuit 3 performs various analog signal processing on the output from the imaging device 2.

  The A / D converter 4 is for converting an analog video signal output from the imaging circuit 3 into a digital video signal.

  The signal processing circuit 5 is for performing various digital signal processings on the video signal output from the A / D converter 4.

  The frame memory 6 is a storage unit that stores various data and the like, and includes an exposure data holding unit 6a for storing a video signal (exposure data) processed by the signal processing circuit 5.

  The FIFO memory 7 is a memory for buffering when displaying or outputting a real-time video.

  The on-screen circuit 8 is a circuit for superimposing character data, photometric area mark data (see photometric area mark 42 in FIG. 7) described later, or other on-screen data on the video signal output from the FIFO memory 7. is there. The data superimposed by the on-screen circuit 8 is output from the first CPU 31.

  The TFT liquid crystal drive circuit 9 controls the TFT panel 10 based on the video signal output from the on-screen circuit 8.

  The TFT panel 10 is capable of color display, and is a display means for displaying a real-time image, various information related to the imaging device, and the like based on the control of the TFT liquid crystal driving circuit 9.

  The backlight unit 11 is provided on the back side of the TFT panel 10 and illuminates the TFT panel 10 from the back side.

  The video output circuit 12 is for outputting the video signal from the on-screen circuit 8 to the outside via the video output terminal 13.

  The video output terminal 13 is a connection terminal for connecting an external video cable or the like.

  The recording buffer 14 performs buffering when the video signal stored in the frame memory 6 is recorded on the recording medium 16. The recording buffer 14 also performs buffering of signals read from the recording medium 16.

  The recording medium interface 15 is for controlling data recording on the recording medium 16 and data reading from the recording medium 16.

  The recording medium 16 is a storage means and is a non-volatile recording medium for recording image data and other various data, and is configured to be detachable from the imaging apparatus, for example.

  The actuator 17 is a drive source for driving the lens 1 to perform autofocus, or to perform automatic zoom when an automatic zoom function is provided.

  The actuator drive circuit 18 controls and drives the actuator 17 based on the control of the first CPU 31.

  The EEPROM 19 is a non-volatile storage medium for storing various data relating to the imaging apparatus, a processing program executed by the first CPU 31 or the second CPU 32, and the like.

  The shake detection unit 21 includes, for example, a gyro sensor, detects angular velocities in the yaw direction and pitch direction generated in the imaging apparatus, and detects shakes of the imaging apparatus based on the detected angular velocities. Shake detection means.

  The external data interface 22 is configured by, for example, a USB or the like, and is an interface for transmitting / receiving data to / from an external device.

  The key matrix 23 is a general term for operation input means including various operation switches and operation buttons provided in the imaging apparatus. Specifically, the key matrix 23 includes a power switch for turning on the power of the imaging apparatus, a release button for inputting a photographing operation, a button for setting whether to perform blur correction, and a blur. It includes buttons for setting the number of correction steps when correction is performed. Further, the key matrix 23 includes an area instruction unit 23a serving as an area designating unit for inputting a region of interest when determining exposure before or after shooting, and an exposure correcting unit for inputting an exposure correction level after shooting. The exposure setting means includes a correction level instruction unit 23b. A signal generated by operating the key matrix 23 is input to the first CPU 31.

  The LCD display circuit 24 is a circuit for controlling the LCD panel 25 to perform various displays based on the control of the first CPU 31.

  The LCD panel 25 is configured to include, for example, a monochrome LCD, and the operation mode such as a shooting mode set in the imaging apparatus, the number of images that can be recorded on the recording medium 16, the shutter speed and the aperture at the time of shooting. It is a display means for displaying information such as values.

  A battery 26 is a main power source of the imaging apparatus.

  The backup power supply 28 is a power supply for supplying power for date display in this imaging apparatus.

  The power supply circuit 27 is a circuit that performs control to supply the power of the battery 26 and the backup power supply 28 to each circuit in the imaging apparatus based on a command from the first CPU 31.

  The battery state detection circuit 29 detects the voltage of the battery 26, etc., calculates the remaining battery level of the battery 26, and outputs the result to the first CPU 31.

  The first CPU 31 is a main CPU, which is a control means for comprehensively controlling each circuit of the image pickup apparatus and also serves as an exposure setting means. The first CPU 31 includes a system control unit 31a for controlling the system of the imaging apparatus. The system control unit 31a includes a divided exposure control unit 31b, a shake correction control unit 31c, and an exposure correction level setting unit. 31d, a histogram calculation unit 31e, a face detection unit 31f, and a corrected display image generation control unit 31g are provided.

  Here, the divided exposure control unit 31b determines the exposure time (shutter time) of the image based on the luminance distribution data obtained from the histogram calculation unit 31e (this exposure time is estimated to be appropriate exposure as described later). The exposure time longer than the time (exposure time for overexposure) is calculated, and the exposure time is divided into a plurality of times to expose a plurality of time-division images. In this way, both the reference exposure amount setting means and the exposure condition calculation means are used.

  Further, the blur correction control unit 31c grasps the positional relationship (blurring state) of a plurality of time-division images photographed under the control of the above-described divided exposure control unit 31b based on the output from the blur detection unit 21. This is a shake correction means for controlling a shake correction amount when image addition is performed by an image adder 32a (to be described later) of the second CPU 32.

  The exposure correction level setting unit 31d is exposure correction means for setting an exposure correction level for an image with a reference exposure amount based on an input from the correction level instruction unit 23b of the key matrix 23 after shooting.

  The histogram calculation unit 31e analyzes the appearance frequency of the pixels for each brightness in the image based on the histogram analysis image (for example, a through image obtained based on the photometric value) acquired before the main photographing, This is a histogram calculation means for outputting the result to the above-described divided exposure control unit 31b.

  The face detection unit 31f detects whether or not an area determined to be a human face is included in the histogram analysis image based on the histogram analysis image acquired before the main photographing.

  Based on the exposure correction level set by the exposure correction level setting unit 31d, the post-correction display image generation control unit 31g generates an image after exposure correction that is displayed on the TFT panel 10. The second CPU 32 is controlled.

  Thus, the first CPU 31 mainly performs control, and the second CPU 32 mainly performs processing for handling image data.

  That is, the second CPU 32 processes the image data stored in the frame memory 6. The second CPU 32 includes an image adding unit 32a, a recorded image generating unit 32b, an image compression / decompression unit 32c, and a recording medium access unit 32d.

  The image addition unit 32a aligns each time-division image based on the control of the shake correction control unit 31c, and then adds each time-division image based on the control of the division exposure control unit 31b, thereby obtaining an exposure correction level setting unit. An exposure image having an exposure level set by 31d is generated, and serves as both an image addition unit and a shake correction unit.

  The recorded image generating unit 32b generates a recorded image for recording on the recording medium 16 based on the exposure image added by the image adding unit 32a.

  The image compression / decompression unit 32 c compresses the recorded image data generated by the recorded image generation unit 32 b and stored in the frame memory 6, for example, JPEG compression, or is compressed image data read from the recording medium 16. Is performed.

  The recording medium access unit 32 d is for controlling access to the recording medium 16 by the recording medium interface 15.

  Next, FIG. 2 is a diagram illustrating a first example of a histogram calculated by the histogram calculation unit 31e.

  The subject in the example shown in FIG. 2 has a relatively high frequency of appearance of intermediate level luminance, a low frequency of appearance of high luminance and low luminance, and a luminance distribution having only one appearance frequency peak for luminance. It has become.

  At this time, the divided exposure control unit 31b determines the shutter speed for each time-division exposure based on the following algorithm.

  First, a reference exposure value α (EV) obtained based on photometry before actual photographing is calculated. In calculating the reference exposure value α (EV), when a photometry method is designated in advance, a value calculated based on the designated photometry method becomes the reference exposure value α. Examples of photometric methods include spot photometry, center-weighted photometry, multi-photometry, and the like. The histogram analysis image shown in FIG. 2 is taken based on the reference exposure value α.

  Next, in the histogram analysis image shown in FIG. 2, the exposure value ε (EV) corresponding to the center of brightness (the median value of the dynamic range) and the exposure value β (EV corresponding to the brightness of the peak of the appearance frequency) ) And.

Subsequently, the absolute value δ of the difference between the exposure value ε (EV) and the exposure value β (EV) is calculated as follows.
δ = ABS (β−ε)
Here, ABS () means taking the absolute value of the value in ().

  Thereafter, the shutter speed of each time-division exposure at the time of actual photographing is calculated as shown in the following equation. Here, it is assumed that the number of time-division exposures is set to nine.

First, for the first time-division exposure,
α-2 × δ (EV)
The shutter speed is set so as to obtain the above exposure. This corresponds to setting a shutter speed at which an image having an exposure distribution as shown by the dotted line in FIG. 2 can be taken.

Subsequent time-division exposure up to n (n = 2 to 9) sheets is the average brightness of the image when the n-th time-division image is added to the first time-division image (photometric method). Is specified, the brightness calculated based on the metering method, and so on)
α− (2 × δ) + (δ / 4) × (n−1) (EV)
The shutter speed is calculated so as to obtain a brightness corresponding to the exposure value, and the difference from the shutter speed similarly calculated for the time-division images up to the (n-1) th image is obtained. The difference shutter speed obtained in this way is set as the shutter speed for the n-th time-division exposure.

  When the shutter speed of each time-division exposure is calculated in this way, thereafter, the control is actually performed to take each time-division image.

  Then, at a desired time point after photographing, at an interval of δ / 4 (EV) from the image of the exposure distribution as shown by the dotted line in FIG. 2 to the image of the exposure distribution as shown by the solid line in FIG. An image having a desired exposure value can be obtained by exposure correction.

  In the above description, since an example of performing nine time-division exposures has been described, the exposure value step is δ / 4 (EV), but in general, m (m is an integer of 2 or more) time-division exposures. In the case of performing, the exposure value step may be set to 2 × δ / (m−1). Also in the other histogram examples described below, the number of images taken by time-division exposure can be changed as appropriate.

  Thus, in the example shown in FIG. 2, the curve shown by the solid line is shifted so that the peak position is symmetrical to the curve shown by the solid line in FIG. 2 across the center (ε) of the dynamic range (FIG. 2). The curve shown by the dotted line) is configured so that exposure correction after photographing can be performed between the peak positions of these two curves.

  Next, FIG. 3 is a diagram illustrating a second example of the histogram calculated by the histogram calculation unit 31e.

  The subject in the example shown in FIG. 3 has a relatively low frequency of appearance of intermediate level luminance, and has a higher frequency of appearance of high luminance and low luminance, and the maximum peak of the appearance frequency is on the high luminance side. In addition, there is a luminance distribution in which the second peak of the appearance frequency exists on the low luminance side, and there are two appearance frequency peaks for the luminance. Such a histogram is seen, for example, when the main subject is in the background of backlight, the background is overexposure, and the main subject is dark and sinking.

  At this time, the divided exposure control unit 31b determines the shutter speed for each time-division exposure based on the following algorithm.

  First, a reference exposure value α (EV) obtained based on photometry before actual photographing is calculated. The histogram analysis image shown in FIG. 3 is taken based on the reference exposure value α.

  Next, in the histogram analysis image shown in FIG. 3, an exposure value ε (EV) corresponding to the center of brightness (median value of the dynamic range) and an exposure value β1 (corresponding to the brightness of the maximum peak of appearance frequency) EV) and an exposure value β2 (EV) corresponding to the brightness of the second peak of the appearance frequency are calculated.

Subsequently, the absolute value δ1 of the difference between the exposure value ε (EV) and the exposure value β1 (EV) and the absolute value δ2 of the difference between the exposure value ε (EV) and the exposure value β2 (EV) are Calculate as follows.
δ1 = ABS (β1-ε)
δ2 = ABS (β2-ε)
The meaning of ABS () is the same as described above.

  Thereafter, the shutter speed of each time-division exposure at the time of actual photographing is calculated as shown in the following equation. It is assumed here that the number of time-division exposures is set to nine.

First, for the first time-division exposure,
α-δ1 (EV)
The shutter speed is set so as to obtain the above exposure. This is equivalent to setting the shutter speed so that an image subjected to exposure correction can be taken so that the maximum peak of the appearance frequency is located at the center of the dynamic range shown in FIG.

In the subsequent time-division exposure up to n (n = 2 to 5) sheets, the average brightness of the image when the time-division image up to the n-th sheet is added to the first time-division image,
α−δ1 + (δ1 / 4) × (n−1) (EV)
The shutter speed is calculated so as to obtain a brightness corresponding to the exposure value, and the difference from the shutter speed similarly calculated for the time-division images up to the (n-1) th image is obtained. The difference shutter speed obtained in this way is set as the shutter speed for the n-th time-division exposure.

In the subsequent time-division exposure up to n (n = 6 to 9) sheets, the average brightness of the image when the n-th time-division image is added to the first time-division image is
α−δ2 + (δ2 / 4) × (n−1) (EV)
The shutter speed is calculated so as to obtain a brightness corresponding to the exposure value, and the difference from the shutter speed calculated as described above with respect to the (n−1) th time-division image is obtained. The difference shutter speed obtained in this way is set as the shutter speed for the n-th time-division exposure.

  When the shutter speed of each time-division exposure is calculated in this way, thereafter, the control is actually performed to take each time-division image.

  Then, from an image in which the maximum peak of the appearance frequency is located at the center of the dynamic range at a desired time after shooting, an image having an exposure distribution as shown by the solid line in FIG. 3 is δ1 / 4 (EV). Δ2 / 4 from the image of the exposure distribution with the desired exposure value in the interval of δ and the image of the exposure distribution as shown by the solid line in FIG. 3 to the image in which the second peak of the appearance frequency is located in the center of the dynamic range. It is possible to obtain an exposure correction with a desired exposure value at an interval of (EV).

  In this way, in the example shown in FIG. 3, when there are a plurality of appearance frequency peaks across the center (ε) of the dynamic range, exposure correction emphasizing any peak is performed as desired after shooting. Is possible.

  Next, FIG. 4 is a diagram illustrating a third example of the histogram calculated by the histogram calculation unit 31e.

  The subject in the example shown in FIG. 4 is basically the same as the subject in the example shown in FIG. However, in the example described with reference to FIG. 4, exposure correction cannot be performed using an interval with the median of the dynamic range, but before and after the reference exposure value by photometry before photographing. The exposure correction can be performed after photographing in a predetermined step.

  That is, the division exposure control unit 31b determines the shutter speed for each time division exposure based on the following algorithm.

  First, a reference exposure value α (EV) obtained based on photometry before actual photographing is calculated. The histogram analysis image shown in FIG. 3 is taken based on the reference exposure value α.

  Next, the range of 1 (EV) before and after this reference exposure value α (EV) is 1/3 (EV) step, and outside this, the range of 2 (EV) before and after reference exposure value α (EV). For the range, the shutter speed for time-division exposure is calculated so that exposure correction can be performed after shooting in steps of 1/2 (EV).

In other words, the number of time-division exposures is 11 here, and for the first time-division exposure,
1st sheet: α-2 (EV)
The shutter speed is set so as to obtain the above exposure.

In the subsequent time-division exposure up to n (n = 2 to 11) sheets, the average brightness of the image when the n-th time division image is added to the first time-division image is The shutter speed is calculated so that the brightness corresponding to the exposure value shown in FIG.
2nd sheet: α−2 + (1/2) = α− (3/2) (EV)
3rd sheet: α-2 + {(1/2) × 2} = α-1 (EV)
4th sheet: α-1 + (1/3) = α− (2/3) (EV)
5th sheet: α-1 + {(1/3) × 2} = α− (1/3) (EV)
6th sheet: α-1 + {(1/3) × 3} = α (EV)
7th sheet: α + (1/3) (EV)
Eighth sheet: α + {(1/3) × 2} = α + (2/3) (EV)
9th sheet: α + {(1/3) × 3} = α + 1 (EV)
10th sheet: α + 1 + (1/2) = α + (3/2) (EV)
11th sheet: α + 1 + {(1/2) × 2} = α + 2 (EV)
Thereafter, the difference between the shutter speed calculated for the n-th time-division image and the shutter speed similarly calculated for the (n−1) -th time-division image is taken. The difference shutter speed obtained in this way is set as the shutter speed for the n-th time-division exposure.

  When the shutter speed of each time-division exposure is calculated in this way, thereafter, the control is actually performed to take each time-division image.

  Then, at a desired time after shooting, the range of 1 (EV) before and after the exposure value α is 1/3 (EV) step, and the outside is 2 (EV) before and after the reference exposure value α (EV). In the range of), exposure correction can be performed in steps of 1/2 (EV).

  Thus, in the example shown in FIG. 4, before and after the reference exposure value based on the photometric result, if it is close to this reference exposure value, it is a fine step, and if it is far from the reference exposure value, it is a slightly rough step, Exposure correction can be performed as desired.

  Next, FIG. 5 is a diagram illustrating a fourth example of the histogram calculated by the histogram calculation unit 31e.

  A curve indicated by a solid line in FIG. 5 indicates a histogram of the entire screen, and is similar to the example indicated by the solid line in FIG. In addition, a curved line indicated by a dotted line in FIG. 5 indicates a histogram of a specific partial area in the entire screen.

  Here, the specific partial area is a predetermined range area in the center of the screen, a partial area designated by a user operation as described later with reference to FIG. 7, or a face detection unit 31f of the first CPU 31. Therefore, the face area specified as described later with reference to FIG.

  In the example shown in FIG. 5, the peak of the histogram of the entire screen is slightly higher than the exposure value ε (EV) corresponding to the brightness at the center of the dynamic range, and the exposure value β (EV). It corresponds.

  In addition, the peak of the histogram in the specific partial area is slightly lower in luminance than the above-described exposure value ε (EV) and corresponds to the exposure value γ (EV).

  At this time, the division exposure control unit 31b determines the shutter speed for each time division exposure based on the algorithm described above with reference to FIG. In other words, the maximum peak of the appearance frequency in FIG. 3 corresponds to the peak of the curve of the entire screen of FIG. 5, and the second peak of the appearance frequency in FIG. 3 corresponds to the peak of the curve of the specific partial region of FIG. For example, the description in FIG. 3 can be applied as it is.

  In this way, the example shown in FIG. 5 can be performed as desired after shooting, regardless of whether the exposure correction is focused on either the entire screen or a specific partial area.

  Next, FIG. 6 is a diagram illustrating a fifth example of the histogram calculated by the histogram calculation unit 31e.

  In FIG. 6, the curve indicated by the solid line and the curve indicated by the dotted line are the same as the curve indicated by the solid line and the curve indicated by the dotted line in FIG.

  In the example shown in FIG. 6, exposure correction can be performed after shooting in a predetermined step before and after the exposure value γ at which a specific partial area is a reference exposure amount. ing.

  That is, the divided exposure control unit 31b determines the shutter speed for each time-division exposure based on the algorithm described above with reference to FIG.

  Thus, in the example shown in FIG. 6, before and after the exposure value γ with a specific partial area as the reference exposure amount, a fine step is obtained when this reference exposure value is close, and a slightly rough step when it is far from the reference exposure value. Thus, exposure correction after shooting can be performed as desired. This makes it possible to finely correct the brightness of the subject at the designated photometric point that the photographer is most interested in.

  In the above description, some examples of how to analyze the histogram and determine the shutter speed for time-division exposure according to the histogram have been described. Can be adopted.

  For example, in the luminance distribution as shown in FIG. 2, the exposure value step between the peak of the appearance frequency and the center of the brightness (the median value of the dynamic range) is finely divided, and the exposure value slightly coarse around the periphery. You may make it time-division exposure in this step. This also has the advantage that when the exposure correction is performed later, it is easy to obtain an image with a more appropriate brightness on the entire screen.

  Further, in the luminance distribution as shown in FIG. 5 or FIG. 6, the exposure value step between the peak of the appearance frequency in a specific partial region and the center of brightness (the median value of the dynamic range) is made finer. The surroundings may be subjected to time division exposure in steps with slightly coarse exposure values. This makes it possible to preferentially finely correct a specific partial area that the photographer wants to photograph most beautifully.

  Further, as will be described later with reference to FIG. 10, the face detection function is used on the histogram analysis image acquired before the main photographing, and the brightness of the area detected as a face is used as a base. Thus, it is conceivable to perform time-division exposure by finely adjusting the step of the exposure value with the brightness before and after that. This makes it possible to perform exposure correction more finely than the other portions of the face portion of a person considered to be the main subject among all subjects.

  When strobe photography is performed, it is conceivable to perform time-division exposure at the shortest time interval immediately after the strobe light is emitted. As a result, it becomes possible to perform exposure correction with finer accuracy after shooting the portion exposed by strobe light, which is often the most dominant illumination when performing flash shooting.

  In addition, when performing time-division exposure, it may be possible to change the light emission method of the strobe. That is, when performing time-division exposure by causing the strobe to emit light, the strobe emits a plurality of times with a minute amount of light in accordance with the timing of time-division exposure, so that one time-division period includes one minute emission period. It is conceivable to perform a plurality of time-division exposures. And, when generating a recorded image, it is possible to variably adjust the influence level of strobe light within the illumination range by adjusting how many time-division images where the strobe emits a small amount of light is added It becomes.

  Note that since the actual luminance distribution of the subject varies, it is preferable to apply an algorithm considered to be most suitable from among a plurality of algorithms as described above based on the result of the histogram analysis.

  Further, when the frame memory 6 or the recording medium 16 has a large capacity, the shutter speed corresponding to the exposure amount obtained by adding the exposure amount having a sufficient margin to the reference exposure amount is finely time-divided so that the short shutter speed is obtained. If a large number of time-division images are taken, an image with a desired exposure amount can be freely obtained thereafter.

  Next, FIG. 7 is a diagram illustrating a display example of the TFT panel 10 when a specific partial region is changed.

  A specific partial area can be changed by operating the area instruction section 23a of the key matrix 23. That is, when the operation of the area instruction unit 23a is performed, the photometry area mark data is output from the first CPU 31 to the on-screen circuit 8, and the photometry area mark 42 as a pointer is displayed on the display screen 41 of the TFT panel 10 (before shooting). In this case, for example, it is displayed so as to be superimposed on a monitor image).

  Then, the photometering area mark 42 can be moved to a desired position in the display screen 41 by operating the area indicating unit 23a including a pointing device such as a cross key. Then, when the photometry area mark 42 has moved to a desired position, the area where the photometry area mark 42 is located is a specific part where spot photometry is performed by operating a confirmation button or the like included in the area instruction section 23a. Determined as an area. When a specific partial area is designated in this way, the above-described photometry method is applied with the specific partial area as the center. That is, for example, spot photometry based only on a specific partial area, center-weighted photometry centered on a specific partial area, multi-photometry centered on a specific partial area, and the like.

  The area instruction unit 23a is not only used when a specific partial area is designated before shooting in order to execute the algorithm of FIGS. 5 and 6, but also described later with reference to FIG. It is also used when a specific partial area is designated in order to perform exposure correction after shooting. The photometry area mark 42 as shown in FIG. 7 is displayed both when a specific partial area is designated before photographing and when a specific partial area is designated after photographing. Yes. Thus, since the partial area can be designated by the same operation using the same operation means while viewing the same display, unified operability without a sense of incongruity can be realized.

  Here, an example in which the photometric area mark 42 is moved within the display screen 41 has been described, but the present invention is not limited to this, and the size of the photometric area mark 42 may be changed. Alternatively, not only one photometric area mark 42 but also a plurality of photometric area marks 42 may be displayed. At this time, a plurality of partial areas become specific partial areas.

  Next, FIG. 8 is a flowchart showing a process of photographing operation by the imaging apparatus.

  When a release button included in the key matrix 23 is operated, this photographing operation is started.

  When this process is started, first, an AE operation is performed to calculate a reference exposure time (step S1).

  Next, an image for histogram analysis is acquired based on the reference exposure time, and the analysis is performed to calculate the number of time division exposures and the exposure time (shutter speed) of each time division exposure (step S2). ).

  Subsequently, time-division exposure conditions (that is, time-division exposure time, etc.) calculated for each time-division exposure are set (step S3), and time-division exposure is performed under the set time-division exposure conditions (step S4). .

  Whenever one time-division exposure is completed, time-division exposure data is read (step S5), and the read time-division exposure data is written to the exposure data holding unit 6a of the frame memory 6 (step S6).

  Thereafter, it is determined whether or not the time-division exposure of the number of times calculated in step S2 is completed (step S7).

  If the predetermined number of time-division exposures have not yet been completed, the process returns to step S3 and the above-described processing is repeated.

  On the other hand, if it is determined that the predetermined number of time-division exposures have been completed, an appropriate number of time-division exposure data is added based on the exposure correction value input from the correction level instruction unit 23b of the key matrix 23. Then, a recorded image is generated (step S8), the generated recorded image is recorded on the recording medium 16 via the recording medium interface 15 (step S9), and this series of photographing operations is finished.

  Next, FIG. 9 is a flowchart illustrating an example of a calculation process of the time-division exposure count and the exposure time of each time-division exposure in step S2 of FIG.

  When this process is started, a histogram analysis image is acquired based on the reference exposure time calculated in step S1 (step S11).

  Next, the brightness with the highest appearance frequency is calculated by performing histogram analysis of the image for histogram analysis (step S12).

  Subsequently, based on the brightness of the reference exposure and the brightness obtained from the histogram analysis in step S12, the shutter speed of each time-division exposure is calculated using the algorithm described above with reference to FIG. Then, the process returns to the process shown in FIG.

  Next, FIG. 10 is a flowchart showing another example of a calculation process of the number of time-division exposures and the exposure time of each time-division exposure in step S2 of FIG.

  When this process is started, a histogram analysis image is acquired based on the reference exposure time calculated in step S1 as in step S11 described above (step S21).

  Then, the face detection unit 31f of the first CPU 31 specifies whether or not a human face exists in the histogram analysis image, and if so, in what position and in what range (if any). Step S22).

  Subsequently, the brightness of the partial region corresponding to the face is calculated by performing histogram analysis of the partial region specified as the face (step S23).

  Thereafter, based on the brightness of the reference exposure and the brightness obtained from the histogram analysis in step S23, the shutter speed of each time-division exposure is used using the algorithm described above with reference to FIG. 5 or FIG. Is calculated (step S24), and the process returns to the process shown in FIG.

  Next, FIG. 11 is a flowchart showing an example of a recorded image generation process in step S8 of FIG.

  When this process is started, a reference exposure value image is first generated by adding time-division images (step S31). The reference exposure image generated here is displayed on the TFT panel 10.

  Next, it waits for the exposure correction correction level to be input from the correction level instruction section 23b (step S32). The correction level instruction unit 23b can be used to perform exposure correction before shooting, but as described here, it is also used to perform exposure correction after shooting. In this way, since the operation means for performing exposure correction is common before and after photographing, unified operability can be realized.

  Subsequently, it is determined whether or not the input correction level exceeds a limit for exposure correction (step S33).

  Here, when it is determined that the input correction level is within a range in which exposure correction is possible, it is determined whether or not the correction is correction for brightening the image (step S34).

  Here, when it is determined that the correction is to brighten the image, a recording image is generated by adding the time-division image by increasing the number of additions according to the correction amount and displayed on the TFT panel 10 ( In step S35), when it is determined that the correction is not to brighten the image, a recording image is generated by adding the time-division image by decreasing the addition number according to the correction amount and displayed on the TFT panel 10 (step S35). Step S36).

  On the other hand, if it is determined in step S33 that the input correction level exceeds the limit for exposure correction, the TFT panel 10 displays that correction cannot be performed (step S37).

  In this way, it is determined whether or not the correction process has been completed when any of the processes of step S35, step S36, or step S37 is performed (step S38). For example, when the user who has observed the corrected image through the TFT panel 10 performs an operation to determine the image as a recorded image, it is determined that the correction process is finished. On the other hand, when the user who has observed the corrected image through the TFT panel 10 performs correction at a different correction level, the process proceeds to step S32 and the above-described processing is performed.

  When it is determined in step S38 that the correction has been completed, the recorded image generation process is terminated.

  Next, FIG. 12 is a flowchart showing another example of the recorded image generation process in step S8 of FIG.

  When this process starts, first, an image based on the brightness at the center of the image is generated by adding the time-division images (step S41). Here, an example of generating an image based on the brightness at the center of the image is given, but a specific partial region is designated before shooting and the algorithm described with reference to FIGS. 5 and 6 is used. When time-division exposure is performed, an image based on the brightness of a specific partial area designated before photographing may be generated. The image generated here is displayed on the TFT panel 10. In addition, a pointer indicating a specific partial area is displayed at the center of the screen or at a designated position so as to be superimposed on this image.

  Next, it waits for the position (target position) of a specific partial area to be input from the area instruction section 23a (step S42). As described above, the area instruction unit 23a is an operation unit that is also used to designate a specific partial area on the monitor screen before the image is captured.

  Subsequently, the brightness of the input specific partial area is calculated (step S43).

  Then, an image addition number is calculated so that the calculated specific partial region has the optimum brightness (step S44).

  Based on the calculated image addition number, it is determined whether or not the exposure correction limit is exceeded (step S45).

Here, when it is determined that the exposure correction is within the range where the exposure can be corrected, a time division image having the calculated addition number is added to generate a recorded image and display it on the TFT panel 10 (step S46).
On the other hand, if it is determined in step S45 that the exposure correction limit has been exceeded, the TFT panel 10 displays that correction cannot be performed (step S47).

  Thus, when the process of step S46 or step S47 is performed, it is determined whether or not the correction process is completed (step S48). For example, when the user who has observed the corrected image through the TFT panel 10 performs an operation to determine the image as a recorded image, it is determined that the correction process is finished. On the other hand, when the user who has observed the corrected image through the TFT panel 10 inputs a different target position, the process proceeds to step S42 and the above-described processing is performed.

  Since such processing is performed, every time the target position (photometry area mark 42) as shown in FIG. 7 moves, an image with an exposure level (addition number of divided images) corresponding to that position is displayed on the TFT panel. 10 is displayed in real time. In this way, it is possible to select an optimum condition while viewing the same image as the finally obtained image.

  Then, when it is determined in step S48 that the correction has been completed, the recorded image generation process is terminated.

  Next, FIG. 13 is a flowchart showing processing for changing the calculation method (photometry method) to a desired value when calculating the brightness of a specific partial area in step S43 of FIG.

  When this process is started, first, the process waits for the photometric method to be input by the key matrix 23 (step S51). The metering method input here is the same as described above, for example, spot metering based only on a specific partial area, center-weighted metering centering on a specific partial area, multi-metering centering on a specific partial area, etc. It is.

  Subsequently, the brightness relating to the specific partial area is calculated by the photometric method input in step S51 (step S52). The brightness calculated here is the brightness in step S43 in FIG.

  Then, when the process of step S52 is performed, the process shown in FIG. 13 is terminated.

  Of course, it is also possible to generate a bracketing-captured image using a plurality of time-division images photographed using the technique described with reference to FIGS. In this case, there is an advantage that bracket shooting can be easily performed by performing only one shooting. That is, in this case, since it is not necessary to perform continuous shooting, it is possible to reduce the shooting time until the bracket shooting is finished and reduce the consumption of the battery and the like. Furthermore, there is almost no difference in shooting time between a plurality of bracket images having different exposure values obtained by generation, so that the image obtained by bracket shooting differs depending on the movement of the subject. Thus, there is no problem with conventional bracket shooting. After shooting, since the bracket shooting variable range, variable number of steps (number of sheets), variable step width, etc. can be adjusted, the most suitable exposure image is obtained after shooting without missing a photo opportunity. It can be easily selected and generated.

  According to the first embodiment, by performing time-division exposure, it is possible to perform exposure correction after shooting. This exposure correction has an advantage that noise and the like are hardly increased unlike the case where image sensitization is simply performed.

  Then, when performing time-division exposure, it is possible to perform positive exposure correction by a predetermined amount after shooting by shooting so that the total exposure amount is larger than the reference exposure amount.

  Further, when the algorithm described with reference to FIG. 2 is used, exposure correction for shifting the peak of the histogram around the center of the dynamic range can be performed.

  On the other hand, when the algorithm described with reference to FIG. 3 is used, it is possible to perform exposure correction that places emphasis on, for example, an overexposed background and a darkly sinking subject.

  Furthermore, when the algorithm as described with reference to FIG. 4 is used, it is possible to finely perform exposure correction for an area close to the reference exposure value, and it is possible to perform exposure correction with higher accuracy.

  When the algorithm described with reference to FIGS. 5 and 6 is used, exposure correction emphasizing a specific partial area can be performed after shooting. At this time, it is possible to set a desired region as a specific partial region by inputting using the region instruction unit 23a.

  Furthermore, since photometric conditions (spot metering such as spot photometry / center-weighted photometry / multi-photometry, or photometry points) can be changed, a reference exposure value image utilizing each photometry condition can be acquired.

  In addition, when a photometric condition centered on a specific partial area is set for the image after shooting, the brightness utilizing each photometric condition can be calculated for this specific partial area.

  At this time, the operation means for designating a specific partial area and the display (GUI: graphic user interface) on the TFT panel 10 at the time of operation are made common before and after photographing, so that they are unified. Operability can be realized.

  In addition, since the operation means for performing exposure correction is common between before and after photographing, more unified operability can be realized.

  Furthermore, if the exposure compensation range is widened and the exposure compensation step is set to be small, it is possible to eliminate the need for exposure compensation work before shooting, which is optimal without missing a photo opportunity. An imaging apparatus capable of obtaining an exposure amount image is obtained.

  Thus, based on a plurality of time-division images obtained by one shooting, an image having a desired exposure level can be obtained with good image quality after shooting. Therefore, shooting failure can be prevented and shooting with a high degree of freedom is possible.

[Embodiment 2]
FIG. 14 to FIG. 16 show Embodiment 2 of the present invention, and FIG. 14 is a flowchart showing processing of photographing operation by the imaging apparatus. In the second embodiment, parts that are the same as those in the first embodiment are given the same reference numerals and description thereof is omitted, and only differences are mainly described.

  In the present embodiment, shake correction can be further performed.

  When the photographing operation shown in FIG. 14 is started, the shake detection unit 21 is initialized after first performing the processing of step S1 and step S2 (step S61).

  Then, after setting the time-division exposure conditions in step S3, the shake correction control unit 31c of the first CPU 31 acquires and holds the shake data from the shake detection unit 21 (step S62).

  Thereafter, the processing of steps S4 to S9 is performed in the same manner as the processing shown in FIG.

  Next, FIG. 15 is a flowchart showing the recorded image generation processing in step S8 of FIG.

  When this process is started, the processes of steps S31 to S34 are performed in the same manner as the process shown in FIG.

  If it is determined in step S34 that the correction is to brighten the image, the relative position of the image to be added is identified based on the blur data (step S71), and the blur correction is performed based on the identified position. Then, the current image is added to the added image (step S72).

  If it is determined in step S34 that the correction is not to brighten the image, an image having the designated brightness is newly added and generated (step S73). This is because the correction for brightening can be generated simply by adding the next time-division image to the image that has already been added, while the correction for darkening can be performed by the same means. This is because it was not possible to create a new one.

  Thus, when any one of step S72, step S73, or step S37 described above is performed, it is determined in step S38 whether or not the correction process has been completed, and when it is determined that the correction has been completed, this recording is performed. The image generation process ends.

  Next, FIG. 16 is a flowchart showing a process for generating an image with the specified brightness by newly performing an addition process in step S73 of FIG.

  When this process is started, first, an image blur amount is calculated based on the blur data (step S81).

  Next, the relative position of the image is specified based on the calculated blur amount (step S82).

  Then, based on the specified position, an image addition process is performed so as to add the pixel values of the pixels at the same position (step S83).

  Thereafter, it is determined whether or not the required number of time-division images have been added (step S84). If the required number of images has not been reached, the process returns to step S81 and the above-described processing is repeated.

  If it is determined in step S84 that the required number of time-division images have been added, this process ends and the process returns to the process shown in FIG.

  According to the second embodiment, the same effects as those of the first embodiment described above can be obtained, and the shake correction is performed after adding the shake correction when adding the time-division images. A recorded image can be generated.

  Although the image processing apparatus applied to the imaging apparatus has been described above, the present invention is not limited to this and can be widely applied to apparatuses that can perform image processing. Alternatively, the time-division image and its exposure condition may be recorded on the recording medium 16, the computer may execute an image processing program, and the recording medium 16 may be read to perform the processing described above. Furthermore, an image processing method may be applied to an existing apparatus or the like to perform the processing as described above.

  In addition, the present invention is not limited to the above-described embodiments, and various modifications and applications can be made without departing from the spirit of the invention.

  The present invention can be suitably used for an image processing apparatus, an image processing program, and an image processing method for processing a plurality of time-division images obtained by capturing images continuously in time.

1 is a block diagram illustrating a configuration of an imaging apparatus according to Embodiment 1 of the present invention. The figure which shows the 1st example of the histogram calculated in the said Embodiment 1 by the histogram calculating part. The figure which shows the 2nd example of the histogram calculated in the said Embodiment 1 by the histogram calculating part. The figure which shows the 3rd example of the histogram calculated in the said Embodiment 1 by the histogram calculating part. The figure which shows the 4th example of the histogram calculated in the said Embodiment 1 by the histogram calculating part. The figure which shows the 5th example of the histogram calculated in the said Embodiment 1 by the histogram calculating part. FIG. 3 is a diagram showing a display example of a TFT panel when changing a specific partial region in the first embodiment. 5 is a flowchart illustrating processing of a shooting operation performed by the imaging apparatus according to the first embodiment. 9 is a flowchart illustrating an example of a calculation process for the number of time division exposures and the exposure time for each time division exposure in step S2 of FIG. 8 in the first embodiment. 9 is a flowchart showing another example of calculation processing for the number of time division exposures and the exposure time of each time division exposure in step S2 of FIG. 8 in the first embodiment. 9 is a flowchart showing an example of a recorded image generation process in step S8 of FIG. 8 in the first embodiment. 9 is a flowchart showing another example of the recorded image generation process in step S8 of FIG. 8 in the first embodiment. 12 is a flowchart showing processing for changing the calculation method (photometry method) to a desired value when calculating the brightness of a specific partial region in step S43 of FIG. 12 in the first embodiment. 7 is a flowchart illustrating processing of a shooting operation performed by the imaging apparatus according to the second embodiment of the present invention. 15 is a flowchart showing recorded image generation processing in step S8 in FIG. 14 in the second embodiment. In the said Embodiment 2, the flowchart which shows the process which performs the addition process newly and produces | generates the image of the designated brightness in step S73 of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Lens 2 ... Image sensor (imaging means)
DESCRIPTION OF SYMBOLS 3 ... Imaging circuit 4 ... A / D converter 5 ... Signal processing circuit 6 ... Frame memory (memory | storage means)
6a ... exposure data holding unit 7 ... FIFO memory 8 ... on-screen circuit 9 ... TFT liquid crystal drive circuit 10 ... TFT panel (display means)
DESCRIPTION OF SYMBOLS 11 ... Backlight unit 12 ... Video output circuit 13 ... Video output terminal 14 ... Recording buffer 15 ... Recording medium interface (recording medium I / F)
16. Recording medium (storage means)
17 ... Actuator 18 ... Actuator drive circuit 19 ... EEPROM
21 ... blur detection unit 22 ... external data interface (external data I / F)
23 ... Key matrix (exposure setting means)
23a ... area designating part (area designating means)
23b... Correction level instruction section (exposure correction means)
DESCRIPTION OF SYMBOLS 24 ... LCD display circuit 25 ... LCD panel 26 ... Battery 27 ... Power supply circuit 28 ... Backup power supply 29 ... Battery state detection circuit 31 ... 1st CPU (exposure setting means)
31a: System control unit 31b: Divided exposure control unit (reference exposure amount setting means, exposure condition calculation means)
31c: Shake correction controller (blur correction means)
31d: Exposure compensation level setting section (exposure compensation means)
31e ... Histogram calculation section (histogram calculation means)
31f: Face detection unit 31g: Image display control unit for post-correction display 32 ... Second CPU
32a ... Image addition unit (image addition means, blur correction means)
32b ... Recorded image generating unit 32c ... Image compression / decompression unit 32d ... Recording medium access unit 41 ... Display screen 42 ... Photometric area mark

Claims (11)

Storage means for storing a plurality of time-division images obtained by continuously shooting in time;
Exposure setting means for setting a desired exposure amount;
Image adding means for adding a plurality of time-division images read from the storage means to generate an added image having an exposure amount substantially equal to the exposure amount set by the exposure setting means;
Display means for displaying the added image generated by the image adding means;
An image processing apparatus comprising: The exposure setting means includes exposure correction means for correcting a predetermined reference exposure in stages.
The image addition means adds a plurality of time-division images read from the storage means to generate an addition image having an exposure amount substantially equal to the exposure amount corrected by the exposure correction means. The image processing apparatus according to claim 1. Reference exposure amount setting means for setting the reference exposure amount;
Histogram calculation means for calculating the frequency distribution of the brightness of the subject based on the image obtained by exposure with the reference exposure amount;
An exposure condition calculation means for obtaining an exposure condition of the time-division image based on the frequency distribution;
An imaging means for capturing the time-division image based on the exposure condition;
Further comprising
The image processing apparatus according to claim 2, wherein the storage unit stores a time-division image captured by the imaging unit.   The exposure condition calculation means can correct an exposure amount corresponding to the peak brightness of the frequency distribution between the brightness of the peak of the frequency distribution and the brightness of the center of the dynamic range of the image. The image processing apparatus according to claim 3, wherein the exposure condition is set.   The exposure condition calculation means sets the exposure condition such that the step width of the exposure amount that can be corrected increases as the difference in exposure amount from the reference exposure amount increases. The image processing apparatus according to 3. It further comprises an area designating means for designating a partial area in the image,
The histogram calculation means calculates a brightness frequency distribution in the partial area,
The image processing apparatus according to claim 3, wherein the exposure condition calculation unit calculates an exposure condition of the time-division image based on a brightness frequency distribution in the partial area. It further comprises an area designating means for designating a partial area in the image,
The image adding means adds a plurality of time-division images read from the storage means so that the exposure amount of the partial area is substantially equal to the exposure amount corrected by the exposure correction means. The image processing apparatus according to claim 2, wherein the image processing apparatus generates the image processing apparatus. The display means displays a pointer indicating the partial area so as to overlap the image.
7. The region specifying means includes a pointing device that allows a pointer displayed on the display means to be moved to a desired position on an image displayed on the display means. The image processing apparatus according to claim 7. Further comprising shake correction means for correcting the shake of the plurality of time-division images,
The image adding means generates an added image having an exposure amount substantially equal to the exposure amount set by the exposure setting means by adding the time-division images whose shakes have been corrected by the shake correction means. The image processing apparatus according to claim 1. On the computer,
Adding a plurality of time-division images obtained by continuously photographing in time to generate an added image having an exposure amount substantially equal to an exposure amount set as desired;
Displaying the generated added image;
An image processing program for executing Adding a plurality of time-division images obtained by continuously photographing in time to generate an added image having an exposure amount substantially equal to an exposure amount set as desired;
Displaying the generated added image;
An image processing method comprising:

Images