JP2006229627A - Digital camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital camera for shortening a bracket photography time. <P>SOLUTION: The digital camera includes a calculation means for reading charge data from an imaging element during exposure, integrating two or more charge data in the time direction, and generating image data; a bracket photographing means for photographing a set of two or more images as a bracket by changing the exposure time of the imaging element; and a control means for carrying out exposure processing of a sheet of image, of which exposure time becomes maximum, out of the set of two or more images, reading out charge data from the imaging element during the exposure processing by using the integrating means, generating image data with shorter exposure time, generating a set of two or more images, and completing the bracket photography. The bracket photography can be finished in a time shorter than the total exposure time of the bracket photography. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a digital camera having a bracket shooting function and shortening the bracket shooting time.

Conventionally, a camera using a silver salt film has a technique called bracket photography in which a photographing condition is changed to adjust an exposure amount to the film to obtain a plurality of photographing results with different brightness. This is often used when it is difficult to set exposure conditions, and there is a possibility that a desired result may not be obtained with a single image.
The shooting conditions for bracket shooting are the aperture amount and exposure time. In addition, in recent digital cameras, photographing with changing white balance (color temperature) and ISO sensitivity has been performed.
On the other hand, a technique for repeating the exposure for a minute time shorter than the exposure time and integrating the exposure to obtain final main image data has already been disclosed in Japanese Patent Laid-Open No. 2001-326850 (Patent Document 1). In this conventional example, the principle of extracting image data from the image sensor during shooting is used as a means for acquiring image data at an arbitrary timing.

Conventional bracket photography is one in which photographing is repeated a plurality of times while changing photographing conditions, and the photographing time is inevitably extended according to the number of times.
FIG. 9 shows the concept. FIG. 9 illustrates the case where three images are obtained by changing the photographing conditions in three stages of desensitization exposure and sensitization exposure in addition to appropriate exposure. For each shooting, it is assumed that the first shooting requires an exposure time of t seconds, the second shooting requires an exposure time of t + α seconds, and the third shooting requires an exposure time of t + β seconds. is doing. As a result, the time taken for photographing the three images can be calculated as at least t + (t + α) + (t + β) seconds. This indicates that the total shooting time is proportionally increased in accordance with the number of frames during bracket shooting, and during that time, the user is burdened. If we consider bracket shooting with a set of five frames, it will be a calculation that requires t + (t + u) + (t + v) + (t + x) + (t + y) + (t + z) seconds. Increasing the time allowed the subject to change more, and also detracted from the meaning of bracket shooting aimed at the same scene.
Japanese Patent Application Laid-Open No. 11-4380 (Patent Document 2) discloses a method of obtaining a plurality of images having different apparent exposure amounts by electrically processing from one image data for bracket shooting. However, since electrical processing is performed, there is a risk of noise being mixed in the final image.
In addition, although the concept of the conventional bracket shown in FIG. 9 is given as an example of a set of three pieces, the applicable range of the present invention is not limited to bracket photography consisting of three pieces. For example, it is effective for a combination of two or more sheets such as a set of 5 or 7 sheets. The t seconds, t + α seconds, and t + β seconds do not indicate fixed values, but are exposure time values that vary depending on the exposure conditions.
JP 2001-326850 A Japanese Patent Laid-Open No. 11-4380

  Therefore, an object of the present invention is to provide a digital camera that shortens bracket shooting time.

In order to achieve the above object, a digital camera according to a first aspect of the present invention includes an integration unit that reads out charge data from an image sensor during exposure, integrates the plurality of charge data in the time direction, and generates image data;
Bracket photographing means for performing bracket photographing for photographing a set of a plurality of images by changing the exposure time of the image sensor;
An exposure process is performed for one image having the longest exposure time in the set of the plurality of images, and the charge data is read from the imaging element by the integrating means during the exposure process, and the exposure Control means for generating the image data with a shorter time, generating the set of the plurality of images, and ending the bracket shooting,
Bracket photography is completed in a shorter time than the total exposure time of the bracket photography.
Furthermore, the digital camera of the second aspect of the present invention determines the standard exposure time of the image sensor according to the photometric result, and the desensitization exposure time and sensitization of the image sensor according to the bracket width (exposure amount width). Predetermining exposure time,
The image data is read when the desensitized exposure time has elapsed from the start of exposure of the image sensor, the image data is subsequently read when the standard exposure time has elapsed, and the image data is read when the sensitized exposure time has elapsed, and the exposure The process ends.
Furthermore, the digital camera of the third aspect of the present invention uses a CMOS image sensor as the image sensor, reads the charge data of the pixel from the CMOS image sensor, generates the image data,
The charge data in the CMOS image sensor is returned to a clear state or is not cleared.

Furthermore, the digital camera of the fourth aspect of the present invention uses a CCD image sensor as the image sensor, arbitrarily reads the charge data, generates the image data, and the charge data in the CCD image sensor is cleared. From the state, accumulation of differential image data for bracketing is started.
Furthermore, the digital camera according to the fifth aspect of the present invention is configured such that the non-exposure time until the readout of the charge data from the image sensor and the start of re-exposure during the exposure is greater than the number of images in the set of the plurality of images. The exposure time of the long-side image is extended to secure the exposure amount.
Furthermore, the digital camera of the sixth aspect of the present invention has a display device, and indicates to the display device that reading of the plurality of image data has been completed when the bracket photographing is completed.

  According to the digital camera of the present invention, exposure processing is performed on one image having the longest exposure time among a set of a plurality of images, and charge data is acquired from the image sensor by the integrating means during the exposure processing. Reading, generating image data with a shorter exposure time, generating a set of the plurality of images, and terminating the bracket shooting, and having a shorter time than the total exposure time of the bracket shooting Ends bracket shooting and reduces shooting time.

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

Hereinafter, a simplified configuration of the digital camera according to the first embodiment of the present invention will be described with reference to FIG.
The lens device 11 is a device having a focusing function, and the diaphragm device 12 and the mirror device 13 are devices that control the path of light incident on the lens device 11.
The shutter device 14 is a shutter means, and the image sensor 15 is a device that converts an optical signal into an electric signal by a CCD, a CMOS, or the like.
The A / D device 16 is a device that converts an analog signal into a digital signal, the image processing device 17 is a device that performs video signal processing such as gamma correction, the compression processing device 18 is a device that performs compression processing of image data, and the memory device 19 is A device that temporarily stores image data and stores and holds programs and data variables, and a recording medium 20 are devices that record image data using a memory card or a hard disk.
The display device 22 is provided in the optical viewfinder 21 and / or on the outer periphery of the camera. For example, the exposure time, the aperture value, the number of shootable images, the exposure correction value, the shooting mode, the compression rate, the focus, the number of brackets, This is a device that displays the end of bracketing, completion of flash charging, busy, and various setting menu screens, playback images, and other warning texts.
The drive device 23 is a device that drives the image sensor 15 and the A / D device 16, and the shutter control device 24 is a device that controls the shutter device 14 and adjusts the exposure time.
The photographing mode changing device 25 is a device that changes the photographing mode. By this photographing mode changing device 25, for example, automatic, program, shutter speed priority, aperture priority, manual, depth of focus priority, portrait, landscape, close-up, sports It is possible to select each shooting mode such as night view, panorama, and moving image recording.
The photographing resolution changing device 26 is a device that changes the resolution of a photographed image, and the ISO value changing device 27 is a device that changes the sensitivity at the time of photographing.
The shutter switch 28 is a device for instructing imaging, and is composed of a two-stage switch SW1 and SW2. When SW1 is turned on, operations such as autofocus processing, automatic exposure processing, auto white balance processing, and flash light control processing are started. Further, when the SW 2 is turned on, the shutter device 14 is opened, and the signal output from the image sensor 15 passes through the A / D device 16, the image processing device 17, and the compression processing device 18, so that image data is generated and stored in the recording medium 20. A series of processing of saving is performed.

The main power switch 29 is a switch for controlling on / off of the power of the digital camera, and the single-shot continuous shooting switch 30 is a switch for switching between single shooting and continuous shooting. After pressing, the mode is switched between continuous shooting (continuous shooting) until SW2 is released and mode (single shooting) in which only one shooting is performed until SW1 is released.
Of course, as a general technique, the exposure time may be controlled directly by the shutter device 14, or a method of controlling by the accumulation time of the imaging device 15 called an electronic shutter is often used.
The bracket shooting instruction device 31 is a device for inputting the number of shots, exposure adjustment amount, and shooting sequence in bracket shooting and bracket shooting. The control device 32 controls the aperture device 12 to adjust the amount of light reaching the image sensor 15. The device and the focus control device 33 are devices that adjust the focal length by driving the focusing lens in the lens device 11.
The sounding body 34 is a device that emits a warning sound or a confirmation sound, the flash device 35 is a device having a function of projecting auxiliary light for autofocus and a flash light control function, the distance measuring device 36 is a device that detects in-focus, and a light measuring device 37 Is a device for detecting the brightness of a subject.
The system control device 38 controls the entire digital camera, the peripheral control device, the control according to the input from the switches, the adjustment of the focal length and the exposure amount, the writing / reading control to the memory and the recording medium, etc. It is.
Here, although distance measurement and photometry (that is, autofocus processing, automatic exposure processing, flash light control processing) are performed using the distance measurement device 36 and the photometry device 37, the image processing device 17 and the system control device are described. It is also possible to substitute by 38.
Further, instead of the optical viewfinder 21, an image entering the imaging device 15 may be displayed on the display device 22 to be a viewfinder used as a viewfinder.
FIG. 13 shows an embodiment expressing the bracket setting.
In a conventional digital camera, a number line such as -3 to +3 is simulated with reference to 0, and black dots in the line are lit to express the number of brackets and the range of sensitization / desensitization.
In addition, the black dot blinks during the bracketing process to express what kind of sensitivity is being shot.

Next, an outline of processing of the digital camera according to the first embodiment of the present invention shown in FIG. 1 will be described with reference to FIG.
First, the system control device 38 checks the state of SW1, and when SW1 is pressed, starts the following processing (S101).
Next, the system control unit 38 checks the setting state of the single-shot continuous shooting switch 30 for switching between single-shot / continuous-shooting (S102), and if the single-shot setting is set, the single-shot flag (exists in the memory device 19). Is set (S103), and if continuous shooting is set, a continuous shooting flag (existing in the memory device 19) is set (S104).
The single shooting flag and the continuous shooting flag may be recorded in a memory inside the system control device 38.
Next, the system control device 38 performs a distance measurement process (S105). The bracket shooting instruction device 31 is checked (S106) to check whether bracket shooting is instructed.
If bracket shooting is not instructed, the number of times of bracket shooting is set to 0, and a variable n for holding the number of times of bracket shooting is set to 0 (S107).
If there is a bracket shooting instruction, the variable n is set to 1 to indicate the start of bracket shooting (S108).
At the same time, the bracket shooting instruction device 31 inputs the step exposure width, the number of shots, and the shooting order in bracket shooting, and holds them in the memory device 19.
At this time, the number of shots is determined, and the available capacity of the memory 19 used for intermediate processing and the recording medium 20 to be recorded is checked (S109) to determine whether the number of shots can be taken. (S110), the process returns to S101.

Next, photometric processing is performed (S111), and the process waits until SW2 is pressed (S112).
If SW2 is not pressed, the state of SW1 is checked (S113). If SW1 is released, the process returns to S101 and enters a standby state.
If SW1 is pressed (S113), the process returns to the photometry process (S111).
If SW2 is pressed (S112), a photographing process is performed (S114), and then a developing process is performed (S115).
The developed image data is temporarily stored in the memory device 19 and then subjected to image compression processing according to the set mode (S116), and the storage processing is performed on the recording medium device 20 such as a hard disk or a memory card. Start (S117).
After the recording is started, it is determined whether or not a plurality of shooting processes as a set of bracket shooting has been completed (S118), and if not completed or originally not bracket shooting, it is determined whether SW2 is ON / OFF ( S121).
If SW2 is pressed, it is determined whether the continuous shooting flag is set (S122), and if it is continuous shooting, the process returns to S106 to return to the determination of whether continuous shooting during bracket shooting or continuous shooting without bracket shooting.
In the case of single shooting, the process returns to the determination of whether or not SW2 is released again (S121).
If SW2 is released (S121), the state of SW1 is checked (S123), and if it is kept pressed, it is checked whether SW2 is pressed again (S121).
If SW1 is released, the process returns to S101 and waits until SW1 is pressed.
In the development process (S115), necessary WB (white balance) integration calculation and OB (optical black) integration calculation are performed, and the calculation result is stored in an internal memory (not shown) of the system control unit 38 or the memory unit 19.
Then, the system control device 38 reads out the captured image data written in a predetermined area of the memory device 19 using the image processing device 17 and uses the calculation result stored in the system control device internal memory 38 or the memory device 19. Then, various development processes including an AWB (auto white balance) process, a gamma conversion process, and a color conversion process are performed (S115).

Next, the ranging process (S105) shown in FIG. 2 will be described with reference to FIG.
First, focus driving of the lens device 11 is performed using the system control device 38, the image sensor 15, the distance measuring device 36, and the focus control device 33, and focusing processing is performed (S201).
Next, a light beam (not shown) incident on the lens device 11 is incident on the distance measuring device 36 by the mirror device 13, and the in-focus state is determined by determining the in-focus state of the image formed as an optical image.
The system control device 38 and the focus control device 33 move the focusing lens in the lens device 11 (S201), and the system control device 38 makes a determination based on the state of the image captured by the distance measuring device 36 (S202).
When the in-focus state is obtained, the lens position is determined, and distance data, lens data, and the like are stored in the internal memory of the system control device 38 or the memory device 19.

Next, the photometric process (S111) shown in FIG. 2 will be described with reference to FIG.
The system control device 38 performs automatic exposure processing using the photometry device 37.
By exposing a light beam (not shown) incident on the lens device 11 to the photometric device 37, the exposure state of the image formed as an optical image is measured (S301), and an optimum exposure (AE) can be obtained during actual photographing. The operation is repeated (S302).
When the set value that can obtain the appropriate exposure is determined (S303), the system control circuit 38 stores the photometric data including the photometric value and / or the set parameter in the internal memory or the memory device 19 of the system control unit 38, and S304. Proceed to
The system controller 38 determines the aperture value (Av value) and the shutter time value (Tv value) according to the exposure amount determined in the photometric process (S303) and the shooting mode set by the mode dial. .
In accordance with this value, the shutter control device 24 and the aperture control device 32 are controlled during the shooting sequence shown in FIG.
There are one or more combinations of the aperture value and shutter time value for one exposure amount. This is because, in order to obtain the same exposure amount, if the aperture is reduced, the exposure time may be extended, and if the exposure time is shortened, the aperture may be opened. In order to select one set value from the combination, the priority order is determined by the setting of the photographing mode changing device 25, and a specific value can be selected.

表１には測光結果によって選択されるシャッター秒時の一例が示され、この
表１から選択される。
ブラケット撮影の場合、測定した測光値に対する標準露光量から、使用者がブラケット撮影指示装置３１で指示した増減感度幅に応じて、まず減感露光時間を算出する（Ｓ３０８）。続いて増感露光時間を算出する（Ｓ３０９）。
露光時間は通常、露光時間テーブルをメモリ装置１９に持ち、露光量±１段の整数倍、加えて±１／２段の整数倍、さらに±１／３の整数倍でのブラケット増減量に対応して、増感／減感の露光時間を選択することが可能である。

Table 1 shows an example of the shutter time selected based on the photometry result.
In the case of bracket photography, first, the desensitization exposure time is calculated from the standard exposure amount with respect to the measured photometric value according to the increase / decrease sensitivity range designated by the user with the bracket photography instruction device 31 (S308). Subsequently, the sensitized exposure time is calculated (S309).
The exposure time usually has an exposure time table in the memory device 19 and corresponds to an increase / decrease amount of the bracket in an integer multiple of ± 1 step of exposure amount, an integer multiple of ± 1/2 step, and an integer multiple of ± 1/3. Thus, it is possible to select the exposure time for sensitization / desensitization.

表１のシャッター秒時に対する±１段幅でブラケット撮影を指示した場合に選択されるシャッター秒時は表２から選択される。
ここで「２」秒が「１」秒に対する増感用に、「１／４０００」秒が「１／２０００」秒に対する減感用に追加されている。また、±１／２、±１／３のブラケット幅に対するシャッター秒時は、基準となるシャッター秒時をＡとすると、

−１／２段 ＝ ２の二乗根 × Ａ
＋１／２段 ＝ Ａ÷ ２の二乗根

−２／３段 ＝ ｛(２の三乗根)の二乗｝× Ａ
−１／３段 ＝ ２の三乗根 × Ａ
＋１／３段 ＝ Ａ÷ ２の三乗根
＋２／３段 ＝ Ａ÷｛（２の三乗根）の二乗｝

−ｎ／２段 ＝ ２の二乗根のｎ乗 × Ａ
＋ｎ／２段 ＝ Ａ÷ ２の二乗根のｎ乗

−ｎ／３段 ＝ ２の三乗根のｎ乗 × Ａ
＋ｎ／３段 ＝ Ａ÷ ２の三乗根のｎ乗

と表現される。
この理論値からシャッター秒時を計算してもよいし、これに近く計算負荷の軽い値をあらかじめメモリ装置１９に保持しておき、計算を簡略化してもよい。

The shutter time selected when the bracket shooting is instructed with a ± 1 step width relative to the shutter time in Table 1 is selected from Table 2.
Here, “2” seconds are added for sensitization for “1” seconds, and “1/4000” seconds are added for desensitization for “1/2000” seconds. In addition, when the shutter time for the bracket widths of ± 1/2 and ± 1/3 is A, the standard shutter time is

-1/2 stage = 2 square root x A
+1/2 stage = A ÷ 2 square root

-2/3 stage = {(square of 2)} × A
-1/3 stage = the cube root of 2 x A
+1/3 stage = A ÷ 2 cube root + 2/3 stage = A ÷ {(square root of 2)}

-N / 2 stage = 2 square root of n 2 × A
+ N / 2 stage = A ÷ n squared root of 2

-N / 3 stage = n-th power of cube of 2 × A
+ N / 3 stage = A ÷ nth power of the cube root of 2

It is expressed.
The shutter time may be calculated from this theoretical value, or a value close to this may be stored in the memory device 19 in advance to simplify the calculation.

ここで、表３は±１／２段単位幅でブラケット撮影を指示した場合に選択されるシャッター秒時の一例が示される。

Here, Table 3 shows an example of the shutter time selected when bracket shooting is instructed with a unit width of ± 1/2 step.

表４は±１／３段単位幅でブラケット撮影を指示した場合に選択されるシャッター秒時の一例が示される。
表３および表４で上記理論式は±１の範囲で示したが、ブラケット範囲を±１段幅に収めるものではなく、この整数倍のブラケット幅が可能であり、理論的には上限下限に制限はなく、限度はカメラ性能に依存する。決定した露光時間はメモリ装置１９または制御装置３８の内部メモリに保持される。
また、従来、ブラケット撮影の増減単位は１／２または１／３と独立して扱われていたが、本実施例ではこれらを混在させることが可能である。
表２、表３、表４から撮像時間を選択し組み合わせ、短時間側から時間に応じて撮像素子１５から電荷データを読み出せばよい。
さらにシステム制御装置３８は、フラッシュが必要か否かを判断し（Ｓ３０５）、フラッシュが必要ならばフラッシュフラグをセットし、フラッシュ３６の充電が完了するまで（Ｓ３０７）充電を行う（Ｓ３０６）。

Table 4 shows an example of the shutter time selected when bracket shooting is instructed with a unit width of ± 1/3 step.
In Tables 3 and 4, the above theoretical formula is shown in a range of ± 1, but the bracket range is not limited to ± 1 step width, and an integral multiple of the bracket width is possible. There is no limit and the limit depends on the camera performance. The determined exposure time is held in the memory device 19 or the internal memory of the control device 38.
Conventionally, the increment / decrement unit of bracket shooting has been handled independently as 1/2 or 1/3, but in the present embodiment, these can be mixed.
It is only necessary to select and combine the imaging times from Tables 2, 3 and 4 and read out the charge data from the imaging device 15 according to the time from the short time side.
Further, the system controller 38 determines whether or not a flash is necessary (S305), sets a flash flag if a flash is necessary, and performs charging until the flash 36 is completely charged (S307) (S306).

Next, the photographing process (S114) shown in FIG. 2 will be described with reference to FIG.
First, the system control device 38 moves the mirror 13 to the mirror-up position by a mirror driving means (not shown) (S401), determines by photometry processing, and is stored in the internal memory or the memory device 19 of the system control device 38. In accordance with the photometric data, the diaphragm control device 32 drives the diaphragm device 12 to a predetermined diaphragm amount (S402).
Next, the system control device 38 clears the charge of the image sensor 15 (S403), starts the charge accumulation of the image sensor 15 (S404), opens the shutter 14 by the shutter control device 24 (S405), and Exposure is started (S406).
If bracket shooting is instructed and the bracket shooting frequency variable n shown in FIG. 2 is set to a value other than 0 (S108), the process proceeds to a bracket shooting sequence (S407).
If bracketing photography is not instructed, the system control device 38 waits for the exposure time to elapse according to the photometric data (S408).
If the exposure time ends, the system control circuit 38 reads out the electric charge from the image sensor 15 (S409), converts it into a digital signal by the A / D device 16, performs development processing by the image processing device 17, and stores it in the memory device 19. (S410).
After the exposure is completed, the system controller 38 closes the shutter 14 by the shutter controller 24 (S412), drives the diaphragm device 12 to the open aperture value by the diaphragm controller 32 (S413), and moves the mirror 13 to the mirror down position. (S414).

Next, bracket shooting according to the first embodiment of the present invention will be described with reference to FIG. 6. At this time, there are parts of image data serving as bracket shooting output in the memory 1, the memory 2, and the memory 3, respectively. Thereafter, the image data is completed in combination.
The image data generated in the shortest time exists in the memory 1, and the second image data is generated by adding the data in the memory 1 and the memory 2 and stored in the memory 2 (S416). Further, the image data in the memory 2 and the memory 3 are added together and stored in the memory 3 as third image data (S417).
Finally, the bracket frequency variable n is set to 3 to indicate that bracket shooting has been completed. Of course, n is set to 3 when the number of brackets is 3, and the determination value of n for the end determination changes according to the number of brackets instructed from the bracket photographing instruction device 31.
For this reason, it is possible to confirm the completion of bracket photographing that has been completed in a shorter time than in the past.

Next, bracket photography (S411) shown in FIG. 5 will be described with reference to the flowchart of FIG.
In FIG. 6, the passage of three exposure times is included, each of which is taken with a standard exposure amount determined by the photometric sequence shown in FIG. 4, with a lower exposure amount, and with increased sensitivity. This is a determination of the passage of exposure time such that shooting is performed with a certain exposure amount.
After the exposure shown in FIG. 5 is started (S406), if bracket shooting is instructed, the elapse of the first exposure time is determined (S501).
If the first exposure time has elapsed, the charge accumulated from the image sensor 15 is read out, and after A / D and development processes are performed, the image data is stored in a first area “ Save to "Memory 1". At this time, the charge in the image sensor 15 is cleared and re-exposure is started.
Next, it is determined whether or not the second exposure time has elapsed (S504). If the second exposure time has elapsed, the accumulated charge is read from the image sensor 15, and each of the A / D and development processes is performed. The data is stored in the second area “memory 2” provided in the memory device 19. Here again, the charge in the image sensor 15 is cleared and re-exposure is started.
Further, it is determined whether or not the third exposure time has elapsed (S507). If the third exposure time has elapsed, the accumulated charge is read from the image sensor 15, and after A / D and development processing, the image data is stored in the memory. The data is stored in a third area “memory 3” provided in the device 19.
Subsequently, the shutter 14 is closed by the shutter control device 24 shown in FIG. 5 (S412), the data in the memory 1 is changed to the first image data, the data in the memory 1 + memory 2 is changed to the second image data, and the memory 1+. By taking the data in the memory 2 + memory 3 as the third image data, the three bracket photographing is finished.
As described above, by extracting the charge data during the longest exposure process shown in FIG. 10 and generating the image data, it is possible to obtain the image data generated by the low-time exposure, thereby greatly reducing the processing time. Can be achieved.
Further, by setting a plurality of extraction timings, extracting charge data as appropriate, and adding them as image data, it is possible to obtain an imaging result with midway sensitivity.

Next, Embodiment 2 of the present invention in which the charge in the image sensor is not cleared after the charge is read from the image sensor will be described with reference to FIG.
In accordance with the flowcharts shown in FIGS. 2 and 5 of the first embodiment of the present invention, the bracket photographing process shown in FIG. 7 is started in the state where the bracket photographing is started.
First, it is determined whether the first exposure time has elapsed from the start of exposure (S601), and if it has elapsed, charge data is read from the image sensor (S602). A / D and development processing are performed and stored in the memory 1 (S603).
Subsequently, it is determined whether the second exposure time has elapsed (S604), and if it has elapsed, the charge data is read from the image sensor (S605). A / D and development processing are performed and stored in the memory 2 (S606).
Further, it is determined whether the third exposure time has elapsed (S607). If it has elapsed, the charge data is read from the image sensor (S608). A / D and development processing are performed and stored in the memory 3 (S609).
In the second embodiment of the present invention, since the charge data in the image sensor 15 is not cleared, the read data becomes the image data of the bracket photographing without being added.
Therefore, in the second embodiment of the present invention, the memory summing process (S416, S417) in FIG. 5 is not necessary.
As described above, as shown in FIG. 11, during the longest exposure process, by extracting the halfway charge data and using it as image data, it is possible to obtain image data generated by low-time exposure. It is possible to greatly reduce the time.
In addition, by setting a plurality of extraction timings and extracting charge data as appropriate to obtain image data, it is possible to arbitrarily obtain a mid-sensitivity imaging result.

Next, Embodiment 3 of the present invention in which the time for reading out the charge data from the image sensor and the time for clearing the charge in the image sensor must be considered will be described with reference to FIG.
In accordance with the flowcharts of FIGS. 2 and 5 of the first embodiment, the bracket photographing process shown in FIG. 8 is started in a state where bracket photographing is started.
It is determined whether the first exposure time has elapsed from the start of exposure (S701), and if it has elapsed, charge data is read from the image sensor (S702). A / D and development processing are performed and stored in the memory 1 (S703).
Subsequently, the second exposure time is determined. If the exposure time calculated by the normal photometry process requires d seconds for reading the charge data and clearing the charge data, the second exposure time is determined. In order to make a determination as a time, an elapse determination is performed with a time obtained by adding d seconds to the original exposure time (S704). If it has elapsed, the charge data is read from the image sensor (S705). A / D and development processing are performed and stored in the memory 2 (S706).
Further, the third exposure time is determined. Similarly to the determination of the second exposure time, when d seconds are required for reading and clearing the charge data, the second exposure time is determined by d seconds. Since it is used, the progress determination is performed with the third exposure time as a time obtained by adding 2d seconds to the original exposure time (S707). If it has elapsed, the charge data is read from the image sensor (S708). A / D and development processing are performed and stored in the memory 3 (S709).
The above shows an example of a set of three sheets. However, in the case of n bracket shooting, when it is determined to finish the m-th image (2 ≦ m ≦ n), it is necessary to read out the charge and clear the charge in the image sensor. When the time is expressed as d seconds, the determination may be made with the time calculated as {original exposure time + (m−1) d} seconds.
As described above, as shown in FIG. 12, by extracting the charge data during the longest exposure process and converting it into image data, it is possible to obtain image data generated by low-time exposure, which greatly increases the processing time. Shortening can be achieved.
In addition, by setting a plurality of extraction timings and extracting charge data as appropriate to obtain image data, it is possible to obtain a mid-sensitivity imaging result.

It is a block diagram of the digital camera of the Example of this invention. It is the flowchart which showed the process of the whole imaging | photography. It is the flowchart which showed the ranging process. It is the flowchart which showed the photometry process. It is the flowchart which showed the imaging | photography process. It is the flowchart which showed the bracket imaging | photography process. It is the flowchart which showed another bracket imaging | photography process. It is the flowchart which showed another bracket imaging | photography process. It is a conceptual diagram of the conventional bracket photography. It is a conceptual diagram of bracket photography of the present invention. It is a conceptual diagram of another bracket imaging | photography of this invention. It is a conceptual diagram of another bracket imaging | photography of this invention. It is explanatory drawing of the display apparatus at the time of bracket display input.

Explanation of symbols

11: Lens device, 12: Aperture device, 13: Mirror device, 14: Shutter device, 15: Image sensor, 16: A / D device, 17: Image processing device, 18: Compression processing device, 19: Memory device, 20 : Recording medium, 21: Optical finder device, 22: Display device, 23: Drive device, 24: Shutter control device, 25: Mode change device, 26: Imaging resolution change device, 27: ISO value change device, 28: Shutter switch Device: 29: Main power switch, 30: Single shooting continuous shooting switch, 31: Bracket shooting instruction device, 32: Aperture control device, 33: Focus control device, 34: Sound generator, 35: Flash device, 36: Distance measuring device 37: photometric device, 38: system control device.

Claims (6)

Accumulating means for reading out charge data from the image sensor during exposure, integrating the plurality of charge data in the time direction, and generating image data;
Bracket photographing means for performing bracket photographing for photographing a set of a plurality of images by changing the exposure time of the image sensor;
An exposure process is performed for one image having the longest exposure time in the set of the plurality of images, and the charge data is read from the imaging element by the integrating means during the exposure process, and the exposure Control means for generating the image data with a shorter time, generating the set of the plurality of images, and ending the bracket shooting,
A digital camera characterized in that bracket photography is completed in a shorter time than the total exposure time of the bracket photography. The standard exposure time of the image sensor is determined according to the photometric result, and the desensitization exposure time and the sensitization exposure time of the image sensor are determined in advance according to the bracket width (exposure amount width),
The image data is read when the desensitized exposure time has elapsed from the start of exposure of the image sensor, the image data is subsequently read when the standard exposure time has elapsed, and the image data is read when the sensitized exposure time has elapsed, and the exposure The digital camera according to claim 1, wherein the processing is terminated. Using a CMOS image sensor as the image sensor, reading the charge data of the pixels from the CMOS image sensor to generate the image data,
The digital camera according to claim 1, wherein the charge data in the CMOS image sensor is returned to a clear state or is not cleared. Using a CCD image pickup device as the image pickup device, arbitrarily reading out the charge data to generate the image data, and storing the difference image data of bracket photography from the state where the charge data in the CCD image pickup device is cleared. The digital camera according to claim 1, which starts.   The exposure time of the longer-side image in the set of the plurality of images is ensured by the presence of the non-exposure time until reading of the charge data from the image sensor and re-exposure start during the exposure. 2. The digital camera according to claim 1, wherein the digital camera is extended for a long time. 6. The digital camera according to claim 1, further comprising: a display device that indicates to the display device that reading of the plurality of image data is completed when the bracket photographing is completed.

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