JP7346094B2 - Imaging device and its control method - Google Patents

Description

The present invention relates to an imaging device and a control method thereof.

2. Description of the Related Art Imaging apparatuses have been proposed that are capable of bulb photography in which a photographer arbitrarily instructs the timing of exposure start and exposure end. In bulb photography, for example, the subject is exposed only while the photographer is pressing the release button, so the subject can be photographed in any time range. Bulb photography is effective, for example, when photographing fireworks and when it is desired to adjust the ever-changing length of the tail of the fireworks.

On the other hand, an imaging apparatus has been proposed that is capable of exposure bracket photography in which a plurality of images with different exposure amounts are sequentially photographed according to a predetermined exposure amount ratio. Furthermore, an imaging device capable of HDR synthesis that expands the dynamic range by composing a plurality of obtained images has been proposed. Patent Document 1 discloses an imaging device that achieves dynamic range expansion by detecting an exposure amount ratio between a long exposure signal and a short exposure signal and performing gain adjustment based on the detected exposure amount ratio. There is. Further, Patent Document 2 discloses an image sensor having a signal holding section that holds a signal for performing focus detection.

Japanese Patent Application Publication No. 2001-339633 Japanese Patent Application Publication No. 2013-172210

In bulb photography, exposure ends in response to an instruction from the photographer to end photography, so the exposure time is uncertain before photography. Therefore, when acquiring a plurality of images at a predetermined exposure ratio, the imaging device needs to determine the exposure conditions for the second and subsequent images after the first image is captured. In addition, in bulb photography, the exposure ends when the photographer instructs the photographer to stop shooting, so compared to photography where the exposure time is set on the camera, the exposure is longer and the exposure time for the second and subsequent shots is also relatively longer. This is a long exposure. Therefore, when performing bulb photography and performing exposure bracket photography or HDR composition, a large time difference occurs between the first photograph and the second and subsequent photographs. In particular, when photographing a moving subject such as fireworks, the position of the subject may shift between multiple images, making it impossible to obtain a desired image. SUMMARY OF THE INVENTION An object of the present invention is to provide an imaging device that can reduce positional shift of a subject while maintaining the exposure ratio when capturing images with different exposure amounts in bulb photography.

An imaging device according to an embodiment of the present invention includes:
An imaging device that terminates exposure and performs charge readout processing in response to an instruction to terminate photography operated by a photographer, the imaging device comprising:
an image sensor in which pixels are two-dimensionally arranged, including a photoelectric conversion section and a plurality of signal holding sections;
Sequential accumulation in which the first accumulation of charge in the first signal holding section and the second accumulation in the second signal holding section are performed, with the accumulation time ratio of the first accumulation and the second accumulation being constant. , a control means for performing repeated control until the start of the charge readout process ,
If the number of repetitions of the sequential accumulation from the start of the repetition of the sequential accumulation until the instruction to end the imaging is greater than a predetermined number of times, the control means may control the control means to control the operation of the sequential accumulation even if the sequential accumulation has not been completed. Start the charge readout process
It is characterized by

According to the imaging device of the present invention, when capturing images with different exposure amounts in bulb photography, it is possible to reduce positional deviation of the subject while maintaining the exposure amount ratio.

1 is a diagram showing the appearance of an imaging device. 1 is an example of a functional block diagram of an imaging device. FIG. 2 is a diagram showing an example of the configuration of an image sensor. FIG. 3 is a diagram illustrating a driving sequence of an image sensor. It is a flow chart explaining control processing of an image pick-up element. FIG. 3 is a diagram showing a timing chart of a driving sequence of an image sensor. FIG. 2 is a diagram illustrating an example of an image obtained by an imaging device. FIG. 2 is a diagram showing a drive sequence of a conventional image sensor. FIG. 2 is a diagram illustrating an image obtained by a conventional imaging device. It is a flow chart explaining control processing of an image pick-up element. It is a flow chart explaining control processing of an image pick-up element. FIG. 2 is a diagram illustrating a timing chart of a driving sequence of an image sensor. It is a flow chart explaining control processing of an image pick-up element. FIG. 2 is a diagram illustrating a timing chart of a driving sequence of an image sensor. FIG. 2 is a diagram illustrating a timing chart of a driving sequence of an image sensor. FIG. 2 is a diagram illustrating an image obtained by an imaging device.

(First embodiment)
FIG. 1 is a diagram showing the appearance of an imaging device according to this embodiment.
The imaging device shown in FIG. 1 is a digital camera. FIG. 1(A) shows the front of the imaging device. FIG. 1(B) shows the back side of the imaging device. The main body section 151 is the main body of the imaging device, and houses an imaging element, a shutter device, a recording medium, etc. therein. The imaging optical system 152 has an aperture and a lens inside. The movable display unit 153 displays various information such as photographic information and images. The display unit 153 has a display brightness range that can display images with a wide dynamic range without restricting the brightness range.

The switch ST154 is an operation member mainly used to take still images. Switch MV155 is an operation member used to start and stop video shooting. The photographing mode selection lever 156 is an operation member used to select a photographing mode. The menu button 157 is an operation member used to shift to an operation mode (function setting mode) for setting the functions of the imaging device. Up/down switches 158 and 159 are operating members used to change various setting values. The dial 160 is an operating member used to change various setting values. The playback button 161 is an operation member used to shift to an operation mode (playback mode) in which video recorded on a recording medium stored in the main body 151 is played back on the display unit 153.

FIG. 2 is an example of a functional block diagram of the imaging device.
The imaging device has an imaging optical system 152 to a wireless I/F 198. The imaging optical system 152 forms an optical image of the subject on the imaging element 184. The image sensor 184 photoelectrically converts the optical image of the subject formed via the imaging optical system 152 into an electrical video signal. Optical axis 180 is the optical axis of imaging optical system 152. The aperture 181 adjusts the amount of light passing through the imaging optical system 152. Aperture control section 182 controls aperture 181. The optical filter 183 limits the wavelength of light incident on the image sensor 184 and the spatial frequency transmitted to the image sensor 184. The image sensor 184 has a sufficient number of pixels, signal readout speed, color gamut, and dynamic range to meet the Ultra High Definition Television standard. The digital signal processing unit 187 performs various corrections on the digital video data output from the image sensor 184, and then compresses the video data. The timing generator 189 outputs various timing signals to the image sensor 184 and the digital signal processor 187.

The system control CPU 178 controls various calculations and the entire imaging device. Video memory 190 temporarily stores image data (video data). Display I/F 191 is an interface for displaying video on display unit 153. The recording medium 193 is a storage means for recording video data, additional data, and the like. The recording medium 193 is, for example, a removable semiconductor memory or the like. The recording I/F 192 is an interface for recording data on the recording medium 193 or reading data from the recording medium 193. External I/F 196 is an interface for communicating with external computer 1000 and the like. Print I/F 194 is an interface for outputting video to printer 1001. Wireless I/F 198 is an interface for communicating with network 199. The switch input section 179 includes a plurality of operation members such as a switch ST154 and a switch MV155.

FIG. 3 is a diagram showing an example of the configuration of an image sensor.
The image sensor 184 includes a plurality of pixels (unit pixels) including a photoelectric conversion section (photodiode) and a plurality of signal holding sections. The plurality of pixels are arranged two-dimensionally in the image sensor 184. In FIG. 3, among the plurality of pixels included in the image sensor 184, a pixel in the first row and first column (1,1) and a pixel in the last row, the mth row and first column (m, 1), are shown. Since the pixel in the 1st row and 1st column (1,1) and the pixel in the m row and 1st column (m, 1) have the same configuration, the constituent elements are numbered with the same number.

One pixel includes a photodiode 500, a first transfer transistor 501A, a first signal holding section 507A, a second transfer transistor 502A, a third transfer transistor 501B, a second signal holding section 507B, and a fourth transfer transistor. It has a transistor 502B. That is, in the example shown in FIG. 3, the pixel has a plurality of (for example, two) signal holding sections 507A and 507B for one photodiode 500. Therefore, according to the image sensor 184 of this embodiment, it is possible to simultaneously obtain the first image A and the second image B with different exposure times.

The pixel also includes a fifth transfer transistor 503, a floating diffusion region 508, a reset transistor 504, an amplification transistor 505, and a selection transistor 506. The basic structure of the image sensor 184 having a signal holding section is disclosed in Patent Document 2, so a description thereof will be omitted.

The first transfer transistor 501A is controlled by a transfer pulse φTX1A. The second transfer transistor 502A is controlled by a transfer pulse φTX2A. The third transfer transistor 501B is controlled by a transfer pulse φTX1B. Further, the fourth transfer transistor 502B is controlled by a transfer pulse φTX2B. Further, the reset transistor 504 is controlled by a reset pulse φRES. Selection transistor 506 is controlled by selection pulse φSEL. Further, the fifth transfer transistor 503 is controlled by a transfer pulse φTX3. Each control pulse is sent out from a vertical scanning circuit (not shown). Further, 520 and 521 indicate power supply lines, and 523 indicates a signal output line.

FIG. 4 is a timing chart illustrating the driving sequence of the image sensor in the first embodiment.
The system control CPU 178 repeats sequential exposure in which a plurality of exposure times with different exposure times are accumulated in the signal holding section of the image sensor 184 while the photographer performs one bulb photography. A first image A and a second image B are obtained. In this embodiment, photography in which exposure is ended and charge readout processing is performed in response to an instruction to end photography by a photographer's operation is described as bulb photography. In bulb photography, the timing at which the instruction to end photography is issued is not determined at the time when the instruction to start photography is given.

At time t1, the photographer operates the switch 154, and the switch input section 179 instructs the system control CPU 178 to start bulb photography. At time t3(1)a, accumulation of signal charges is started. After T_REL seconds have elapsed from time t1, at time t1e, the photographer operates the switch 154, and the switch input section 179 instructs the system control CPU 178 to end bulb photography. Then, at time t6, the image signal is read out. One photographing operation is performed through the series of operations described above.

The instruction to end the photographing is given by an operation by the photographer during the photographing. Therefore, at time t1 when the photographer issues an instruction to start imaging, time t1e at which the photographer issues an instruction to end imaging and time t6 at which the charge is read from the signal holding unit in response to the instruction to end imaging are not determined.

The image sensor 184 has many rows of pixel columns in the vertical direction. FIG. 4 illustrates drive timing for pixels in the first row. The control described with reference to FIG. 4 is performed by vertically scanning the horizontal synchronizing signal φH, thereby performing the accumulation operation of all pixels of the image sensor 184.

At time t1, the release signal REL becomes high level. Since bulb photography is performed, the photographer continues to press the switch 154 for a certain period of time, and REL also remains at a high level for a certain period of time. At time t2, when the transfer pulses φTX2A(1) and φTX2B(1) in the first row become high level, the first transfer transistor 502A and the second transfer transistor 502B in the first row are turned on. At this time, the reset pulse φRES(1) of all rows has already become high level and the reset transistor 504 is in the on state, so the floating diffusion region 508 of the first row, the first signal holding section 507A, and the second The signal holding unit 507B is reset. When the reset is completed, the first row transfer pulses φTX2A(1) and φTX2B(1) become low level. Note that at time t2, the selection pulse φSEL(1) in the first row is at a low level, and the transfer pulse φTX3(1) is at a high level.

At time t3(1)a, accumulation of signal charges (first accumulation) for obtaining the first image A is started. The first accumulation is accumulation of signal charges in the first signal holding section 507A. At time t3(1)a, when the transfer pulse φTX3(1) in the first row becomes low level, the fifth transfer transistor 503 is turned off, the reset of the photodiode 500 in the first row is released, and the photodiode 500 Accumulation of signal charges starts at . At time t4(1)a, when the first row transfer pulse φTX1A(1) becomes high level, the first transfer transistor 501A is turned on. Then, the signal charges accumulated in the photodiode 500 are transferred to the first signal holding section 507A that holds the charges in the first row.

At time t5(1)a, when the first row transfer pulse φTX1A(1) becomes low level, the first transfer transistor 501A is turned off, and the signal charges accumulated in the photodiode 500 are transferred to the first signal holding section. The transfer to 507A ends. At the same time, the transfer pulse φTX3(1) in the first row becomes high level, the fifth transfer transistor 503 is turned on, the photodiode 500 in the first row is reset, and the signal charge accumulation in the photodiode 500 ends. do.

The period from time t3 (1) a to time t5 (1) a corresponds to the first accumulation time Ta = 1/480 seconds related to the first accumulation to obtain the first image A, and the period increases to the right. This is illustrated as the accumulation A(1) in the shaded area.

At time t3(1)b, accumulation of signal charges (second accumulation) for obtaining the second image B is started. The second accumulation is accumulation of signal charges in the second signal holding section 507B. At time t3(1)b, when the transfer pulse φTX3(1) in the first row becomes low level, the fifth transfer transistor 503 is turned off, the reset of the photodiode 500 in the first row is released, and the photodiode 500 Accumulation of signal charges starts at . At time t4(1)b, when the transfer pulse φTX1B(1) in the first row becomes high level, the third transfer transistor 501B is turned on, and the signal charges accumulated in the photodiode 500 are transferred to the charges in the first row. The signal is transferred to the second signal holding unit 507B that holds the signal.

At time t5(1)a, when the first row transfer pulse φTX1B(1) becomes low level, the third transfer transistor 501B is turned off, and the signal charges accumulated in the photodiode 500 are transferred to the second signal holding section. The transfer to 507B ends. At the same time, the transfer pulse φTX3(1) in the first row becomes high level, the fifth transfer transistor 503 is turned on, the photodiode 500 in the first row is reset, and the signal charge accumulation in the photodiode 500 ends. do.

The period from time t3(1)b to time t5(1)b corresponds to the first accumulation time Tb (1/1920 seconds) to obtain the second image B, and the accumulation in the diagonally shaded area upward to the right Illustrated as B(1). The accumulation time Tb of accumulation B(1) for obtaining the second image B is shorter than the accumulation time Ta of accumulation A(1) for obtaining the first image A. That is, the storage times for the first signal holding section 507A and the second signal holding section 507B are different.

In this embodiment, accumulation in the first signal holding unit 507A for obtaining the first image A and accumulation in the second signal holding unit 507B for obtaining the second image B are performed sequentially. , described as an accumulation set or sequential accumulation.

As described above, the first accumulation set is completed by accumulation A(1) for obtaining the first image A and accumulation B(1) for obtaining the second image B. Thereafter, the second accumulation set A(2), B(2), the third accumulation set A(3), B(3), ..., the nth accumulation set A( n) and B(n) are performed sequentially. The drive sequence for each of these accumulations is the same as the drive sequence explained for accumulations A(1) and B(1), and at the time indicating the drive sequence for each accumulation, (2), (3), . . . The subscript (n) is added and the explanation is omitted.

In this embodiment, the accumulation times of accumulation A(1) to A(n) are the same, Ta=1/480 seconds. Furthermore, the accumulation times of accumulation B(1) to B(n) are the same, Tb=1/1920 seconds. The time from the start of a certain accumulation set until the next accumulation set is started or an image signal is read out is defined as an accumulation set period dT. That is, the accumulation set cycle dT is a cycle in which accumulation sets (sequential accumulation) are repeated. The accumulation set period dT is equal for each accumulation set during one imaging session. Further, the accumulation set period dT is predetermined before the first accumulation of one shooting (accumulation A(1) in the example shown in FIG. 4) is started.

The ratio of the accumulation time of accumulation B(1) to the accumulation time of accumulation A(1) is defined as accumulation time ratio R(1). As mentioned above, the accumulation times of accumulations A(1) to A(n) are equal, Ta=1/480, and the accumulation times of accumulations B(1) to B(n) are equal, Tb=1/1920. . Therefore, the accumulation time ratio R is constant during one shooting, and is expressed as the following equation (1).
R=R(1)=R(2)=...=R(n)=Tb/Ta=(1/1920)/(1/480)=1/4...Formula (1)
That is, in this embodiment, the system control CPU 178 performs charge readout processing for the first signal holding section 507A and the second signal holding section 507B, which are the plurality of signal holding sections, while keeping the accumulation time ratio R constant. The accumulation is repeated in sequence until the start of the process.

FIG. 5 is a flowchart illustrating an example of an image sensor control process.
With reference to FIG. 5, control regarding charge accumulation and readout during bulb photography will be described. In S101, the system control CPU 178 starts control processing. In S102, system control CPU 178 detects release signal REL. Subsequently, in S103, the system control CPU 178 determines whether the release signal REL is at a high level. If the release signal REL is at a high level, the system control CPU 178 determines that an instruction to start bulb photography has been given. The process then proceeds to S104. If the release signal REL is not at high level, the process returns to S102.

Next, in S104, the system control CPU 178 performs a reset process and an accumulation start process. The reset process is a process of resetting the first row floating diffusion region 508, first signal holding section 507A, and second signal holding section 507B. Furthermore, the accumulation start process is a process for starting accumulation of pixels in the first row. The reset processing and accumulation start processing for the first row and subsequent rows are sequentially performed in parallel with the steps after S104.

In S105, the system control CPU 178 detects the release signal REL again. Subsequently, in S106, the system control CPU 178 determines whether the release signal REL is at a low level. If the release signal REL is at a low level, the system control CPU 178 determines that an instruction to end bulb photography has been given, and the process proceeds to S107. If the release signal REL is not at low level, the process returns to S105.

Next, in S107, the system control CPU 178 obtains the total number n of accumulated sets including those currently in execution. Then, in S108, the system control CPU 178 determines whether the accumulation B(n) has ended. If the accumulation B(n) has not been completed, the process returns to S108. If the accumulation B(n) is completed, the process advances to S109. Then, in S119, the system control CPU 178 executes a read process. The readout process is to output the charges accumulated in the signal holding section to the outside as an image signal. After the read process, the control process ends in S110.

According to the operation described above, when the release signal REL becomes low level due to the photographer's operation during the n-th accumulation set, the system control CPU 178 performs accumulation A(n) and accumulation B(n). The read process is executed after the data has been read. That is, after receiving an instruction to end imaging, the readout process is performed after sequential accumulation in the first signal holding unit 507A and the second signal holding unit 507B is completed. According to the operation described with reference to FIG. 5, the number of times of accumulation in the first signal holding section 507A and the second signal holding section 507B is the same.

Returning to FIG. 4, the explanation of the drive sequence will be continued. At time t3(n)a, the system control CPU 178 starts accumulation A(n), and then at time t1e, the photographer operates the switch 154, and the release signal REL becomes low level. Thereafter, according to the flowchart shown in FIG. 5, accumulation A(n) is completed at time t5(n)a. Further, at time t3(n)b, accumulation B(n) starts, and at time t5(n)b, accumulation B(n) is completed.

Next, at time t6, when the reset pulse φRES(1) in the first row becomes a low level, the reset transistor 504 in the first row is turned off, and the reset state of the floating diffusion region 508 is released. At the same time, when the first row selection pulse φSEL(1) becomes high level, the first row selection transistor 506 is turned on, making it possible to read out the image signal of the first row. Furthermore, when the transfer pulse φTX2A(1) in the first row becomes high level, the first transfer transistor 502A in the first row is turned on. An output signal corresponding to a change in the potential of the floating diffusion region 508 is read out to the signal output line 523 via the amplification transistor 505 and the selection transistor 506. The read signal is supplied to a readout circuit (not shown), and is outputted to the outside as an image signal of the first row corresponding to the first image A. That is, the charges in the first signal holding section 507A are read out. When the output is completed, the first row transfer pulse φTX2A(1) becomes low level.

At time t7, when the transfer pulse φTX2B(1) in the first row becomes high level, the second transfer transistor 502B in the first row is turned on. Then, the image signal of the first row corresponding to the second image B is outputted to the outside. That is, the charges in the second signal holding section 507B are read out. When the output is completed, the second row transfer pulse φTX2B(1) becomes low level. At time t8, the selection pulse φSEL(1) of the first row becomes low level, and the reset pulse φRES(1) of the first row becomes high level, completing the read processing of the first row.

Note that the timing chart regarding the pixels in the second row is executed in synchronization with the horizontal synchronization signal φH immediately after time t1. That is, the timing charts for all rows are started between time t1 and time t6. For example, it is assumed that the timing chart of the m-th row is started by the horizontal synchronization signal φH at time t0. The switch signals in this timing chart can be expressed as φSEL(m), φRES(m), φTX3(m), φTX1A(m), φTX1B(m), φTX2A(m), and φTX2B(m). The timing chart for each row is similar to the timing chart for the first row, and the readout process is performed after the storage is completed.

The total sum of accumulation time to obtain the first image A is the first exposure time Ta_all. Further, the total sum of accumulation time to obtain the second image B is defined as the second exposure time Tb_all. When the ratio of the second exposure time Tb_all to the first exposure time Ta_all is defined as the exposure time ratio R_all, the exposure time ratio R_all is equal to the accumulation time ratio R and is 1/4. That is, the exposure amount for obtaining the first image A and the exposure amount for obtaining the second image B are determined according to a predetermined accumulation time ratio R. For example, in the drive sequence described with reference to FIG. 4, the ratio of the exposure amount for obtaining the second image B to the exposure amount for obtaining the first image A is 1/4. The drive sequence described above makes it possible to maintain the exposure amount ratio when obtaining images with different exposure amounts during bulb photography.

FIG. 6 is a diagram illustrating a timing chart corresponding to a driving sequence of an image sensor by the image pickup apparatus of the first embodiment. FIG. 6 shows only the timing of accumulation, release signal, and readout. Although FIG. 6 illustrates a case where the number n of accumulated sets is, for example, 4 or 3, the number n of accumulated sets is not limited to the example shown in FIG. 6.

With reference to FIG. 6, the effects achieved by the imaging device of the first embodiment will be described.
FIG. 6A shows a driving sequence of the image sensor 184 when n=4. After T_REL seconds have elapsed from time t1, the release signal REL becomes low level at time t1e during accumulation A(4). According to the flowchart of FIG. 5, reading becomes possible at time t6 after accumulation B(4) is completed. That is, the read process is performed after the accumulation set consisting of accumulation A(n) and accumulation B(n) is completed.

FIG. 6(B) shows another example of the driving sequence of the image sensor. In FIG. 6(B), unlike FIG. 6(A), after T_REL2 seconds have elapsed from time t1, the release signal REL becomes low level at time t1e2 immediately before the end of accumulation B(4). In this way, even if the release signal REL becomes low level during accumulation B(n), readout is performed after the accumulation set consisting of accumulation A(n) and accumulation B(n) is completed according to the flowchart in FIG. Processing takes place.

FIG. 6C shows another example of the driving sequence of the image sensor. In FIG. 6C, unlike FIG. 6A, the release signal REL becomes low level at time t1e3, immediately after accumulation A(4) is started, after T_REL3 seconds have elapsed from time t1. Even in such a case, the reading process is performed after the accumulation set consisting of accumulation A(n) and accumulation B(n) is completed according to the flowchart of FIG.

In this embodiment, the accumulation time ratio R is constant for the first signal holding section 507A and the second signal holding section 507B, which are a plurality of signal holding sections, and the accumulation is repeated sequentially until the start of the read process. It will be done. Then, after the sequential accumulation in the first signal holding section 507A and the second signal holding section 507B is completed, the charges in the first signal holding section 507A and the second signal holding section 507B are read out. As explained with reference to FIGS. 6(A) to 6(C), in bulb photography, the exposure amount corresponding to the first image A and the exposure amount corresponding to the second image B are determined regardless of the timing of the release signal REL. The ratio to the exposure amount (exposure amount ratio) is constant.

FIG. 6(D) shows another example of the driving sequence of the image sensor. In FIG. 6(D), the accumulation set period dT and accumulation times Ta and Tb of FIG. 6(A) are changed. In the first accumulation set consisting of accumulations A(1) and B(1), the accumulation set period dT and accumulation times Ta and Tb are dT1, Ta1, and Tb1, respectively. In the second accumulation set and subsequent accumulation sets consisting of accumulation A(2) and B(2), the accumulation set period dT and accumulation times Ta and Tb are dT2, Ta2, and Tb2, respectively, and the first accumulation Different from the set. However, the accumulation set period dT corresponding to the number n of accumulation sets is determined in advance before photographing. dT1, Ta1, and Tb1 are each set longer than dT2, Ta2, and Tb2.

In the example shown in FIG. 6(D), the accumulation time ratio R is expressed as in the following equation (2).
R=Tb1/Ta1=Tb2/Ta2...Formula (2)
The accumulation set period dT and the accumulation times Ta and Tb may be constant during one imaging session, or may be variable during one imaging session. Even if the accumulation set period dT and the accumulation times Ta and Tb are variable, the first image A and the second image B are With this, the exposure amount ratio can be maintained at a predetermined value. According to instructions from the photographer or the camera, the accumulation time ratio R in the accumulation set may be kept constant within a specific period of one shooting, and the exposure amount ratio within the specific period may be kept constant. That is, according to the imaging device of the present embodiment, when capturing images with different exposure amounts in bulb photography, it is possible to maintain the exposure amount ratio at a predetermined value.

FIG. 7 is a diagram illustrating an example of an image obtained by the imaging device of this embodiment.
In FIG. 7(A), a subject O is shown. The subject O is moving at a constant velocity V in the X direction indicated by the arrow in the field of view Fi corresponding to the frame Fr of the image obtained by the imaging device. Movement of the subject O within the field of view Fi occurs due to a change in the relative position of the subject O and the imaging device. Therefore, the movement of the object O in the field of view Fi may be caused by the movement of the object O as shown in FIG. 7(A), or may be caused by the movement of the imaging device, It may be caused by both. When the subject O is exposed according to the timing chart shown in FIG. 6(A) or FIG. 6(B), a first image A and a second image B as described below are obtained.

FIG. 7(B) is a diagram showing the first image A obtained by the imaging device of this embodiment. The imaging device sequentially accumulates signals in a plurality of signal holding units while performing one shooting. Therefore, the images obtained in each accumulation to obtain the first image A are recorded in a superimposed manner. Furthermore, since the subject O is moving, each image is recorded with a slight shift in the moving direction. Therefore, regarding the first image A, within the frame Fr, images A1 to A4 of the subject O obtained by accumulations A(1) to A(4) are shifted little by little in the X direction, which is the moving direction of the subject O. are recorded overlappingly.

FIG. 7C is a diagram showing a second image B obtained by the imaging device of this embodiment. Similar to the first image A, for the second image B, images B1 to B4 of the subject O obtained by accumulation B(1) to B(4) are in the frame Fr in the moving direction of the subject O. The images are recorded in an overlapping manner with slight shifts in a certain X direction.

In the example shown in FIG. 7, the second exposure time Tb_all is shorter than the first exposure time Ta_all, so the second image B is captured darker than the first image A. As described above, the ratio of exposure amounts between the first image A and the second image B is determined according to the predetermined accumulation time ratio R. Therefore, by storing the first image A and the second image B separately, the imaging device can obtain an image equivalent to exposure bracket photography. Further, the system control CPU 178 included in the imaging device may combine the first image A and the second image B to obtain an image with an expanded dynamic range. Details of HDR synthesis are disclosed in Patent Document 1.

FIG. 8 is a timing chart corresponding to a drive sequence of a conventional image sensor.
Symbols similar to those in this embodiment are distinguished by a comma ('). As shown in FIG. 8, the release signal REL becomes low level at time t1e after T_REL seconds have elapsed from time t1.

The first accumulation A'(1) starts from time t1. In the example shown in FIG. 8, the accumulation set consisting of accumulation A and accumulation B is not repeated. When the release signal REL becomes low level at time t1e, the accumulation A'(1) ends and the accumulation time Ta' is determined. Accumulation B'(1) for an accumulation time Tb' determined according to a predetermined accumulation time ratio R is executed, and a read process is performed at time t6'. In the above drive sequence, the first image A and the second image B, which have a predetermined exposure amount ratio, are acquired. The accumulation time ratio R is expressed as in the following equation (3).
R=Tb'/Ta'...Formula (3)

FIG. 9 is a diagram illustrating an image obtained by a conventional imaging device.
The subject is the same as the subject O shown in FIG. 7(A), so illustration is omitted. FIG. 9A shows a first image A' obtained by a conventional imaging device. Unlike this embodiment, accumulation is not repeated sequentially in a plurality of signal holding sections during one photographing period, so a single image corresponding to the first image A' is recorded. Furthermore, since the subject O is moving, each image is stretched in the moving direction and recorded. Therefore, regarding the first image A', the image A1' of the subject O obtained in the storage A'(1) is stretched and recorded in the X direction, which is the moving direction of the subject O, within the frame Fr.

FIG. 9(B) shows a second image B' obtained by the conventional imaging device. Similar to the first image A', for the second image B', the image B1' of the subject O obtained in the accumulation B'(1) is in the X direction, which is the moving direction of the subject O, in the frame Fr. It is enlarged and recorded. Since the accumulation time Tb' is shorter than the accumulation time Ta', the second image B' is captured darker than the first image A'.

The effects of the imaging device of this embodiment will be described in comparison with the conventional example described with reference to FIGS. 8 and 9.
As shown in FIG. 7(B), the center of the images A1 to A4 recorded in the first image A in the X direction is defined as the center Ca. Further, as shown in FIG. 7(C), the center of the images B1 to B4 recorded in the second image B in the X direction is defined as the center Cb. As shown in FIG. 6(A), time tca is the temporal center of gravity of accumulation A(1) to accumulation A(4), and time tca is the temporal center of gravity of accumulation B(1) to accumulation B(4). The time between time tcb and time tcb is assumed to be α seconds. α is the time between the center times of adjacent accumulations A and B (A(3) and B(2)). If the switching time required when switching storage is Tsw, α is expressed as in the following equation (4).
α=Ta/2+Tb/2+Tsw...Formula (4)
Further, the difference dx in the X direction between the center Ca and the center Cb in the frame Fr, that is, the positional shift of the subject, is expressed as in the following equation (5).
dx=V×α=V×(Ta/2+Tb/2+Tsw) ...Formula (5)

On the other hand, in the conventional example, as shown in FIGS. 9A and 9B, the center of the image A1' recorded in the first image A' in the X direction is the center Ca', and the second The center of image B1' recorded in image B' in the X direction is represented by center Cb'.

In addition, as shown in FIG. 8, the time between time tca', which is the temporal center of gravity of accumulation A'(1), and time tcb', which is the temporal center of gravity of accumulation B'(1), is α' seconds. shall be. α is the time between the center times of adjacent accumulations A'(1) and B'(1). Assuming that the switching time required when switching storage is Tsw, which is the same as in this embodiment, α' is expressed as in the following equation (6).
α'=Ta'/2+Tb'/2+Tsw...Formula (6)

Further, in the conventional example, the difference dx' in the X direction between the center Ca' and the center Cb' in the frame Fr, that is, the positional shift of the subject, is expressed as in the following equation (7).
dx'=V×α'=V×(Ta'/2+Tb'/2+Tsw)...Formula (7)

As described above, in this embodiment, the accumulation is sequentially repeated in a plurality of signal holding units during one imaging session, so the accumulation time Ta for one time is different from the accumulation time Ta' of the conventional example. It's small compared to The same applies to the accumulation for obtaining the second image B, and the accumulation time Tb is smaller than the accumulation time Tb' of the conventional example. Therefore, from equations (6) and (7), dx in this embodiment is smaller than dx' in the conventional example. That is, according to the imaging device of this embodiment, it is possible to reduce the positional deviation of the subject between the first image A and the second image B.

Further, as shown in FIG. 7(B), the length of the images A1 to A4 recorded in the first image A in the X direction is represented by La. Further, as shown in FIG. 7(C), the length of the images B1 to B4 recorded in the second image B in the X direction is represented by Lb. La is determined by the distance that the subject O moves during the time βa from the start of accumulation A(1) to the end of accumulation A(4). Further, Lb is determined by the distance that the subject O moves during the time βb from the start of accumulation B(1) to the end of accumulation B(4). βa and βb are shown in FIG. 6(A).

βa, βb, and the difference between them, dβ, are expressed as in the following equations (8) to (10).
βa=(Ta+Tb+Tsw×2)×(n-1)+Ta...Formula (8)
βb=(Ta+Tb+Tsw×2)×(n-1)+Tb...Formula (9)
dβ=βa-βb=Ta-Tb=(1-R)×Ta...Formula (10)

On the other hand, in the conventional example, as shown in FIG. 9A, the length of the image A1' recorded in the first image A' in the X direction is represented by La'. Further, as shown in FIG. 9(B), the length of the image B1' recorded in the second image B' in the X direction is represented by Lb'. La' is determined by the distance that the subject O moves during the time βa'=Ta' from the start to the end of the accumulation A'(1). Further, Lb' is determined by the distance that the subject O moves during the time βb'=Tb' from the start to the end of the accumulation B'(1).

In the conventional example, βa', βb', and dβ', which is the difference between them, are expressed as in the following equation (11).
dβ'=βa'-βb'=Ta'-Tb'=(1-R)×Ta'...Formula (11)
As described above, in this embodiment, the accumulation is sequentially repeated in a plurality of signal holding units during one imaging session, so the accumulation time Ta for one time is different from the accumulation time Ta' of the conventional example. It's small compared to From equations (10) and (11), dβ of this embodiment is smaller than dβ′ of the conventional example. That is, in this embodiment, the difference in length between the image recorded in the first image A and the image recorded in the second image B is smaller than that in the conventional case. Therefore, according to the imaging device of this embodiment, it is possible to reduce the positional deviation of the subject between the first image A and the second image B. As described above, according to the imaging device of this embodiment, when images with different exposure amounts are taken in bulb photography, it is possible to reduce the positional shift of the subject while maintaining the exposure amount ratio.

(Second embodiment)
A second embodiment of the present invention will be described. The same parts as those in the first embodiment are given the same numbers and the explanation will be omitted. The main difference between the second embodiment and the first embodiment is that the accumulation set period is set based on subject information.

FIG. 10 is a flowchart illustrating control processing of the image sensor in the second embodiment.
The steps different from the flowchart shown in FIG. 5 will be mainly explained. If it is determined in the determination process of S103 that the release signal REL is at a high level, the system control CPU 178 determines that an instruction to start bulb photography has been given, and the process proceeds to S121. In S121, the system control CPU 178 acquires subject information. The subject information is subject brightness information used for automatic exposure control (AE) and the like. Subsequently, in S122, an accumulation set cycle dT is set based on the subject information. The process then proceeds to S105.

The processing in S121 and S122 will be specifically explained. The system control CPU 178 acquires brightness information using a predetermined program diagram, lookup table, etc., based on the F value of the aperture 181 and information on the ISO sensitivity set in the image sensor 184 and the like. That is, the system control CPU 178 obtains object information by back calculating the brightness information of the object based on the signal amount obtained from the live view image or the like and the shooting conditions. Then, the system control CPU 178 sets the accumulation set period dT based on a table or the like in which the acquired subject information and the accumulation set period dT are linked in advance. Note that the accumulation set period dT may be determined by calculation. For example, the accumulation set period dT may be obtained by predicting the accumulation time Ta based on the subject information and dividing the predicted accumulation time Ta by a predetermined number. Note that the program diagram and lookup table may be stored in memory in advance, or may be obtained via the external I/F 196.

Additionally, the scenes targeted by bulb photography are often very low-light, but point light sources such as stars and outdoor lights are relatively bright. If such a point light source exists, you may choose to selectively determine the subject by limiting the area for acquiring luminance information, or adjust the luminance so that it is underexposed compared to normal shooting. Information may also be obtained. That is, the imaging device of the present embodiment sets a cycle in which accumulation is repeated sequentially in a plurality of signal holding units according to subject information before the accumulation in the signal holding unit is started.

The time from time t1e when the release signal REL becomes low level to the time when two image readout processes are performed in this embodiment will be described. As shown in FIG. 6A, the time from time t1e when the release signal REL becomes low level to time t6 when the two image readout processes are performed is assumed to be γ. The shorter γ is, the shorter the time from when the photographer issues an instruction to end photography to when an image is actually acquired, which is desirable. As shown in FIG. 6(B), γ becomes the minimum at time γ2 from the end of storage B(4) until reading becomes possible. Furthermore, as shown in FIG. 6C, γ becomes maximum at time γ3 from the start of accumulation A(4) until readout becomes possible. Therefore, the range of γ is expressed as in equation (12) below.
γ2≦γ≦γ3=Ta+Tsw+Tb+γ2=(1+R)×Ta+Tsw+γ2
...Formula (12)

On the other hand, in the conventional example, as shown in FIG. 8, if γ' is the time from time t1e when the release signal REL becomes low level to time t6' when the two images are read out, γ' is , is expressed as the following equation (13).
γ'=Tsw+Tb'+γ2=R×Ta'+Tsw+γ2...Formula (13)

The condition that γ3 of this embodiment is smaller than γ' of the conventional example is expressed as in the following equation (14).
(1+R)×Ta<R×Ta'...Formula (14)
That is, Ta<R/(1+R)×Ta'. Therefore, by making the accumulation time Ta sufficiently small, γ becomes smaller than γ' in the conventional example, regardless of the timing of the release signal.

The system control CPU 178 may predict the time when the photographer will instruct the end of bulb photography based on the subject information, and set the accumulation set period dT. From the brightness information of the subject, it is possible to predict the total exposure time that the photographer would consider appropriate for the exposure conditions of the image to be captured. That is, a time corresponding to the accumulation time Ta' of the conventional example is predicted. Based on this accumulation time Ta', the accumulation time Ta can be determined from equation (14) and the accumulation set period dT can be set so that γ is within a predetermined allowable time. According to the imaging device of this embodiment, an effect can be obtained in that the time from when the photographer issues an instruction to end photography to when an image is actually acquired is shortened.

On the other hand, when the accumulation time Ta is reduced, the number n of accumulation sets repeated during the predicted total exposure time increases. As the number n of accumulation sets increases, the number of times the accumulation is switched between the plurality of signal holding sections increases, and the influence of noise due to switching increases. For example, if the same amount of switching noise is applied to accumulation A and accumulation B that have the same number of accumulations but different exposure amounts, there is a risk that an error will occur in the exposure amount ratio between the first image A and the second image B. be. Therefore, it is desirable to reduce the influence of noise by setting a lower limit to the accumulation time Ta or the accumulation set period dT according to the predicted total exposure time. The system control CPU 178 may estimate the subject information from the shooting mode set in advance by the photographer. Further, the system control CPU 178 may use scene information as object information, or may determine brightness information as object information based on the results of multiple shots.

(Third embodiment)
FIG. 11 is a flowchart illustrating control processing of the image sensor in the third embodiment.
The steps different from the flowchart shown in FIG. 5 will be mainly explained. If it is determined in the determination process of S108 that the accumulation B(n) has not been completed, the process proceeds to S131. In S131, the system control CPU 178 determines whether the absolute value of the difference between the current accumulation time ratio Rn and the predetermined accumulation time ratio R is smaller than a threshold value (tolerance value E). The current accumulation time ratio Rn is the ratio between the total accumulation time to obtain the first image A at the current time and the total accumulation time to obtain the second image B at the current time. If the absolute value of the difference between the current accumulation time ratio Rn and the accumulation time ratio R is not smaller than the allowable value E, the process returns to S108. If the absolute value of the difference between the current accumulation time ratio Rn and the accumulation time ratio R is smaller than the allowable value E, the system control CPU 178 will cause the first image A and the second image B to It is determined that the exposure amount ratio is within a predetermined range. The process then advances to S109. That is, even if the accumulation set is not completed and the accumulation A and accumulation B are not the same number of times, the accumulation is immediately ended and the read processing is performed.

FIG. 12 is a diagram illustrating a timing chart corresponding to the driving sequence of the image sensor by the image pickup apparatus of the third embodiment.
FIG. 12A particularly illustrates a driving sequence of the image sensor 184 when n=i. After T_REL4 seconds have elapsed from time t1, the release signal REL becomes low level at time t1e4 during accumulation A(i), which is Tr seconds after the start of accumulation A(i). The current accumulation time ratio Rn is expressed as the following equation (15).
Rn=Tb×(i-1)/(Ta×(i-1)+Tr)...Formula (15)

T_REL4 is sufficiently smaller than T_REL5 shown in FIG. 12(B) when n=j. That is, i is sufficiently smaller than j, and the absolute value of the difference between the current accumulation time ratio Rn and the accumulation time ratio R is greater than the allowable value E. Therefore, accumulation A(i) and accumulation B2(i) are performed according to the flowchart of FIG. 11, and reading becomes possible at time t6. In accumulation B2(i), accumulation ends when the absolute value of the difference between the current accumulation time ratio Rn and the accumulation time ratio R becomes smaller than the allowable value E.

FIG. 12B particularly illustrates a driving sequence of the image sensor 184 when n=j. After T_REL5 seconds have elapsed from time t1, the release signal REL becomes low level at time t1e5 during accumulation A(j), which is Tr seconds after the start of accumulation A(j). The current accumulation time ratio Rn is expressed as the following equation (18).
Rn=Tb×(j-1)/(Ta×(j-1)+Tr)...Formula (16)

T_REL5 is sufficiently larger than T_REL4 shown in FIG. 12(A). That is, j is sufficiently larger than i, and the absolute value of the difference between the current accumulation time ratio Rn and the accumulation time ratio R is smaller than the allowable value E. Accordingly, according to the flowchart of FIG. 11, the accumulation A(j) ends at time t1e4 and can be read at time t6.

As described with reference to FIG. 12, the imaging device of the third embodiment performs the read process in a state where the absolute value of the difference between the current accumulation time ratio Rn and the accumulation time ratio R is smaller than the allowable value E. According to the third embodiment, as in the first embodiment, compared to the case where accumulation A(n) and accumulation B(n) are performed, the image is actually displayed after the photographer issues an instruction to end shooting. This has the effect of shortening the time it takes to obtain the information.

(Fourth embodiment)
FIG. 13 is a flowchart illustrating control processing of the image sensor in the fourth embodiment.
The steps different from the flowchart shown in FIG. 5 will be mainly explained. If it is determined in the determination process of S108 that the accumulation B(n) has not been completed, the process proceeds to S141. In S141, the system control CPU 178 determines whether the number n of accumulated sets is greater than a predetermined threshold N. In FIG. 4, the number of accumulation sets n is the number of times the accumulation set is repeated from time t3(1)a when repetition of the accumulation set (sequential accumulation) starts to time t1e when the photographer gives an instruction to end the shooting. . Therefore, the determination process in S141 corresponds to determining whether the number of repetitions of sequential accumulation is greater than a predetermined number of times. If the number of accumulated sets n is not greater than the threshold N, the process returns to S108. If the number of accumulation sets n is greater than the threshold N, that is, if the number of repetitions of sequential accumulation is greater than a predetermined number, the system control CPU 178 controls the exposure of the first image A and the second image B even if the accumulation is immediately terminated. It is determined that the quantity ratio is within a predetermined range. The process then advances to S109. That is, even if the accumulation set is not completed and the accumulation A and accumulation B are not the same number of times, the accumulation is immediately ended and the read processing is performed.

FIG. 14 is a diagram illustrating a timing chart corresponding to the driving sequence of the image sensor by the image pickup apparatus of the fourth embodiment.
FIG. 14A particularly illustrates a driving sequence of the image sensor 184 when n=i. Further, FIG. 14B particularly illustrates a driving sequence of the image sensor 184 when n=j. In the example shown in FIG. 14, the accumulation time Ta is shorter than the accumulation time Tb. That is, the system control CPU 178 starts the accumulation set, which is sequential accumulation, with accumulation in the first signal holding unit 507A, which has a short accumulation time.

In the example shown in FIG. 14A, after T_REL6 seconds have passed since time t1, the release signal REL becomes low level at time t1e6, which is Tr seconds after the start of accumulation A(i). In this example, since i is less than or equal to N, accumulation A(i) and accumulation B(i) are performed according to the flowchart of FIG. 13, and reading becomes possible at time t6.

Further, in the example shown in FIG. 14B, after T_REL7 seconds have elapsed from time t1, the release signal REL becomes low level at time t1e7, which is Tr seconds after the start of accumulation A(j). In this example, j is greater than N, so according to the flowchart of FIG. 13, the accumulation A(j) ends at time t1e7 and can be read at time t6.

As in the example in FIG. 14(B), even if the accumulation set is not completed, when the charge in the signal holding section is read out, an error in the exposure amount ratio between the first image A and the second image B may occur. The maximum is the case where it is read immediately after the accumulation A(n). In this case, Tr becomes equal to the accumulation time Ta, and the maximum error Emax is expressed as in the following equation (17).
Emax=|Tb×(j-1)/(Ta×(j-1)+Tr)-R|
= |Tb×(j-1)/(Ta×j)-R| ...Formula (17)

In the fourth embodiment, unlike the first embodiment, Ta is shorter than the accumulation time Tb. Therefore, it is possible to obtain the effect that the maximum error Emax can be reduced.
Note that if the time from the start of the accumulation set, that is, the repetition of sequential accumulation until the end of imaging is instructed, is longer than a predetermined time, the system control CPU 178 reads out the charges even if the sequential accumulation has not been completed. Alternatively, the process may be started.

(Fifth embodiment)
FIG. 15 is a diagram illustrating a timing chart corresponding to the driving sequence of the image sensor by the image capturing apparatus of the fifth embodiment.
The same parts as those in the first embodiment are given the same numbers and the explanation will be omitted. In the fifth embodiment, the accumulation time Ta and the accumulation time Tb are equal. That is, the accumulation time for the first signal holding section 507A and the accumulation time for the second signal holding section 507B are equal. Further, the system control CPU 178 combines the first image A and the second image B, which have the same accumulation time.

After T_REL8 seconds have elapsed from time t1, the release signal REL becomes low level at time t1e8 during accumulation A(n). As in the first embodiment, accumulation A(n) and accumulation B(n) are performed according to the flowchart in FIG. 5, and reading becomes possible at time t6.

FIG. 16 is a diagram illustrating an image obtained by the imaging device of the fifth embodiment.
The subject is the same as the subject shown in FIG. 7(A). Similarly to FIG. 7, the case where n=4 is illustrated. FIG. 16(A) shows a first image A obtained by the imaging device of the fifth embodiment. In the frame Fr, images A1 to A4 of the subject O obtained in the accumulations A(1) to A(4) are recorded in an overlapping manner with slight shifts in the X direction, which is the moving direction of the subject O.

Moreover, FIG. 16(B) shows a second image B obtained by the imaging device of the fifth embodiment. In the second image B, images B1 to B4 of the subject O obtained in the accumulations B(1) to B(4) are overlapped in the frame Fr with slight shifts in the X direction, which is the moving direction of the subject O. recorded. Since the accumulation time Ta and the accumulation time Tb are equal, the first image A and the second image B have the same brightness.

FIG. 16(C) shows a third image C obtained by combining the first image A and the second image B. By combining, the third image C becomes an image brighter than the first image A and the second image B. That is, the system control CPU 178 can obtain images with different exposure amounts by combining the images obtained from the first signal holding section 507A and the second signal holding section 507B. By saving the first image A or the second image B and the third image C separately, it is possible to obtain images with different exposure amounts, and it is possible to obtain images equivalent to exposure bracket shooting. It becomes possible. Further, by combining the first image A or the second image B and the third image C, it becomes possible to perform HDR combining to obtain an image with an expanded dynamic range.

The plurality of signal holding units applied in this embodiment is not limited to two signal holding units. In the fifth embodiment, for example, an arbitrary number of three or more signal holding units may be used, depending on the number of images with different exposure amounts used for HDR composition. When an image sensor with three signal holding sections is used, three images with the same exposure amount are obtained, so exposure can be done in three stages: an image without combining, an image with two images, and an image with three images combined. Images with different amounts are obtained. The present invention is not limited to the first to fifth embodiments described above. Any one of the first embodiment to the fifth embodiment may be combined arbitrarily.

(Other embodiments)
The present invention provides a system or device with a program that implements one or more of the functions of the embodiments described above via a network or a storage medium, and one or more processors in the computer of the system or device reads and executes the program. This can also be achieved by processing. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

178 System control CPU
189 Timing generation section

Claims (12)

An imaging device that terminates exposure and performs charge readout processing in response to an instruction to terminate photography operated by a photographer, the imaging device comprising:
an image sensor in which pixels are two-dimensionally arranged, including a photoelectric conversion section and a plurality of signal holding sections;
Sequential accumulation in which the first accumulation of charge in the first signal holding section and the second accumulation in the second signal holding section are performed, with the accumulation time ratio of the first accumulation and the second accumulation being constant. , a control means for performing repeated control until the start of the charge readout process ,
If the number of repetitions of the sequential accumulation from the start of the repetition of the sequential accumulation until the instruction to end the imaging is greater than a predetermined number of times, the control means may control the control means to control the operation of the sequential accumulation even if the sequential accumulation has not been completed. Start the charge readout process
An imaging device characterized by: The imaging apparatus according to claim 1, wherein the control means starts the readout process of the charge after the sequential accumulation is completed when there is an instruction to end the imaging. An imaging device that terminates exposure and performs charge readout processing in response to an instruction to terminate photography operated by a photographer, the imaging device comprising:
an image sensor in which pixels are two-dimensionally arranged, including a photoelectric conversion section and a plurality of signal holding sections;
Sequential accumulation in which the first accumulation of charge in the first signal holding section and the second accumulation in the second signal holding section are performed, with the accumulation time ratio of the first accumulation and the second accumulation being constant. , a control means for performing repeated control until the start of the charge readout process,
The control means performs sequential accumulation in which the first accumulation and the second accumulation are performed sequentially, and maintains a constant accumulation time ratio between the first accumulation and the second accumulation until an instruction to end the photographing is given. If the instruction to end the shooting is repeatedly given , and the ratio of the sum of the accumulation times related to the first accumulation and the sum of the accumulation times related to the second accumulation is smaller than the threshold, the sequential accumulation is performed. An imaging apparatus characterized in that the charge readout process is started even if the charge reading process is not completed. An imaging device that terminates exposure and performs charge readout processing in response to an instruction to terminate photography operated by a photographer, the imaging device comprising:
an image sensor in which pixels are two-dimensionally arranged, including a photoelectric conversion section and a plurality of signal holding sections;
Sequential accumulation in which the first accumulation of charge in the first signal holding section and the second accumulation in the second signal holding section are performed, with the accumulation time ratio of the first accumulation and the second accumulation being constant. , a control means for performing repeated control until the start of the charge readout process,
If the time from the start of the repetition of the sequential accumulation until the instruction to end the imaging is longer than a predetermined time, the control means may perform the charge readout process even if the sequential accumulation has not been completed. An imaging device characterized by starting. The imaging device according to any one of claims 1 to 4 , wherein the control unit sets a cycle for repeating the sequential accumulation based on subject information. The imaging device according to any one of claims 1 to 4 , wherein the set period is constant. The imaging device according to claim 5 , wherein the set period is variable. The control means starts the sequential accumulation from the first accumulation,
The imaging device according to any one of claims 1 to 7 , wherein the first accumulation has a shorter accumulation time than the second accumulation. The first accumulation and the second accumulation have equal accumulation times;
8. The image forming apparatus according to any one of claims 1 to 7 , further comprising a synthesizing means for synthesizing a first image obtained by the first accumulation and a second image obtained by the second accumulation. The imaging device described. An imaging device that has an image sensor in which pixels each including a photoelectric conversion section and a plurality of signal holding sections are arranged in a two-dimensional manner, and that finishes exposure and performs charge readout processing in response to an instruction to end shooting by a photographer's operation. A method for controlling a device, the method comprising:
Sequential accumulation in which the first accumulation of charge in the first signal holding section and the second accumulation in the second signal holding section are performed, with the accumulation time ratio of the first accumulation and the second accumulation being constant. , a step of performing repeated control before the start of the charge readout process ,
In the step, if the number of repetitions of the sequential accumulation from the start of the repetition of the sequential accumulation until the instruction to end the photographing is greater than a predetermined number of times, the process may be performed even if the sequential accumulation has not been completed. Start charge readout process
A control method characterized by: An imaging device that has an image sensor in which pixels each including a photoelectric conversion section and a plurality of signal holding sections are arranged in a two-dimensional manner, and that finishes exposure and performs charge readout processing in response to an instruction to end shooting by a photographer's operation. A method for controlling a device, the method comprising:
Sequential accumulation in which the first accumulation of charge in the first signal holding section and the second accumulation in the second signal holding section are performed, with the accumulation time ratio of the first accumulation and the second accumulation being constant. , a step of performing repeated control before the start of the charge readout process,
In the step, the first accumulation and the second accumulation are carried out sequentially, with the accumulation time ratio of the first accumulation and the second accumulation being constant until an instruction to end the imaging is given. , when the instruction to end the shooting is repeatedly given and the ratio of the sum of the accumulation times related to the first accumulation and the sum of the accumulation times related to the second accumulation is smaller than the threshold, the sequential accumulation is performed. A control method characterized in that the charge readout process is started even if it has not been completed. An imaging device that has an image sensor in which pixels each including a photoelectric conversion section and a plurality of signal holding sections are arranged in a two-dimensional manner, and that finishes exposure and performs charge readout processing in response to an instruction to end shooting by a photographer's operation. A method for controlling a device, the method comprising:
Sequential accumulation in which the first accumulation of charge in the first signal holding section and the second accumulation in the second signal holding section are performed, with the accumulation time ratio of the first accumulation and the second accumulation being constant. , comprising a step of performing repeated control before the start of the charge readout process.
In the step, if the time from the start of the repetition of the sequential accumulation until the instruction to end the imaging is longer than a predetermined time, the charge readout process is performed even if the sequential accumulation has not been completed. Start
A control method characterized by :

Images