JP2017118342A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus configured appropriately to accurately acquire a black level of an effective pixel signal even in a configuration that only a little OB pixels are disposed.SOLUTION: An imaging apparatus comprises: a solid-state imaging device including multiple dummy pixels each having no photoelectric transducer; and acquisition means which sets the number of times of reading of each dummy pixel to multiple times and acquires a reference black level signal for correcting a black level of an effective pixel of the solid-state imaging device based on at least partial signals among signals of the dummy pixels that are read out just the set times.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a photographing apparatus that acquires a black level of an effective pixel using a dummy pixel.

  A solid-state imaging device such as a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor is mounted on the photographing apparatus. A dark current is generated in the output signal of this type of solid-state imaging device depending on sensitivity, temperature at the time of photographing, exposure time, and the like. Therefore, the black level offset component of the effective pixel varies. Therefore, in addition to normal effective pixels having photoelectric conversion elements, optical black (hereinafter referred to as OB (Optical Black)) pixels in which the photoelectric conversion elements are shielded by a light shielding film are formed in the solid-state imaging device. .

  The output signal of the OB pixel includes a dark current component equivalent to the output signal of the effective pixel depending on sensitivity, shooting temperature, exposure time, and the like. Therefore, the signal output level of the OB pixel is clamped as a black level, and the output signal of the effective pixel is subtracted from the clamped black level, so that the offset component of the black level caused by the dark current is between frames or between fields. Variability is suppressed.

  A solid-state imaging device having dummy pixels that do not have photoelectric conversion elements is also known. By clamping the signal output level of the dummy pixel as a black level, improper clamping that can occur when the OB pixel has a pixel defect is avoided.

  Patent Document 1 describes a specific configuration example in which the signal output level of a dummy pixel can be clamped as a black level. Patent Document 1 exemplifies a configuration in which the black level is adjusted by adding or subtracting the signal output difference between the OB pixel and the dummy pixel to the output signal of the effective pixel clamped based on the output signal of the dummy pixel. ing.

JP 2007-27845 A

  The number of OB pixels that can be arranged is limited in order to achieve a reduction in the size of the solid-state imaging device and an increase in the effective pixel area. Therefore, for example, it is difficult to accurately correct the black level of the output signal of the effective pixel even when the output signal of the OB pixel that has been arranged in a small number due to restrictions is averaged and clamped as a black level. Problems are pointed out.

  The present invention has been made in view of the above circumstances, and its object is to obtain the black level of an effective pixel signal with high accuracy even in a configuration in which only a small number of OB pixels are arranged. It is an object to provide a suitably configured photographing apparatus.

  An imaging apparatus according to an embodiment of the present invention is set by setting a solid-state imaging device having a plurality of dummy pixels that do not have photoelectric conversion elements, and setting the number of readings of each dummy pixel to a plurality of times according to imaging conditions. Acquisition means for acquiring a reference black level signal for correcting the black level of the effective pixel of the solid-state imaging device based on at least a part of the signals of each dummy pixel read out a number of times. .

  In one embodiment of the present invention, the acquisition unit performs A / D conversion on the signal output from each dummy pixel a set number of times, and performs predetermined processing based on the A / D converted signal for a plurality of times. The reference value may be calculated, and the calculated reference value may be acquired as a reference black level signal.

  In addition, the imaging apparatus according to an embodiment of the present invention is acquired based on each dummy pixel based on an estimation unit that estimates a dark current component included in an output signal of an effective pixel, and the estimated dark current component. It is also possible to provide a correction means for correcting the reference black level signal.

  Moreover, the imaging device according to an embodiment of the present invention may include a mechanical shutter for controlling the amount of light incident on the solid-state imaging device. In this configuration, the acquisition unit may read at least part of each dummy pixel during a period in which the mechanical shutter is open.

  In one embodiment of the present invention, the acquisition unit may read each dummy pixel after reading all effective pixels of the solid-state imaging device.

  In one embodiment of the present invention, the solid-state imaging device may have a plurality of optical black pixels. In this configuration, the acquisition unit acquires the reference black level signal based on each dummy pixel when the shooting condition satisfies a predetermined condition, and replaces the signal of each dummy pixel when the shooting condition does not satisfy the predetermined condition. Thus, the signal of each optical black pixel may be read, and the reference black level signal may be acquired based on the read signal of each optical black pixel.

Here, the predetermined condition is, for example,
The ISO sensitivity set for the solid-state image sensor exceeds a predetermined sensitivity,
The shooting temperature of the solid-state image sensor exceeds the specified temperature,
The exposure time of the solid-state image sensor exceeds a predetermined time,
At least one of the following.

  In one embodiment of the present invention, when the signal of each dummy pixel is read, the acquisition unit reduces the number of read rows of each optical black pixel from the initially set number of read rows, and each optical black pixel When the above signal is read, the number of read rows of each dummy pixel may be reduced from the initially set number of read rows.

  According to an embodiment of the present invention, there is provided an imaging apparatus that is suitably configured to accurately acquire the black level of an effective pixel signal even when only a small number of OB pixels are arranged.

It is a block diagram which shows the structure of the imaging device which concerns on one Embodiment of this invention. It is a figure which shows typically the structure of the imaging surface of the image pick-up element with which the imaging device which concerns on one Embodiment of this invention is equipped. It is a figure which shows the flowchart of the image generation process performed by the imaging device which concerns on one Embodiment of this invention. It is a figure which shows the drive sequence at the time of imaging | photography by the imaging device which concerns on one Embodiment of this invention.

  An imaging apparatus according to an embodiment of the present invention will be described below with reference to the drawings. In the following, a digital single lens reflex camera will be described as an embodiment of the present invention. Note that the photographing apparatus is not limited to a digital single lens reflex camera, but includes, for example, a mirrorless single lens camera, a compact digital camera, a video camera, a camcorder, a tablet terminal, a PHS (Personal Handy phone System), a smartphone, a feature phone, a portable game machine, and the like. The apparatus may be replaced with another type of apparatus having a photographing function.

[Configuration of the photographing apparatus 1]
FIG. 1 is a block diagram showing a configuration of a photographing apparatus 1 according to an embodiment of the present invention. As shown in FIG. 1, the photographing apparatus 1 includes a photographing lens system 10 (photographing lenses 11 and 12). A diaphragm 13 is disposed between the photographing lens 11 and the photographing lens 12. A mirror 14 is disposed behind the taking lens system 10. The mirror 14 is a half mirror, and is disposed in a posture in which the half mirror surface is about 45 ° with respect to the optical axis AX of the photographing lens system 10.

  A luminous flux from the subject (subject luminous flux) passes through the taking lens system 10 and enters the mirror 14. Behind the mirror 14, a focal plane shutter 15 and a solid-state imaging device 16 are arranged in this order from the mirror 14 side. Above the mirror 14, a diffusion plate (focus plate or focus plate) 18 and a pentaprism 17 are arranged in this order from the mirror 14 side.

  Part of the subject luminous flux incident on the mirror 14 is reflected by the mirror 14 and incident on the pentaprism 17 via the diffusion plate 18. The diffusion plate 18 is disposed at a position equivalent to the imaging surface of the solid-state imaging device 16. Therefore, the subject light flux that has passed through the photographic lens system 10 forms an image on the diffusion plate 18. The pentaprism 17 has a plurality of reflection surfaces, and forms an erect image by reflecting an object image formed and incident on the diffusion plate 18 by each reflection surface, and emits the image toward the eyepiece lens 19. The eyepiece 19 re-images the subject image formed on the diffusion plate 18 and erected by the pentaprism 17 into a virtual image suitable for the photographer's observation. Thereby, the photographer can observe the subject image by looking into the eyepiece lens 19.

  The operation member 32 includes various switches necessary for the user to operate the photographing apparatus 1, such as a power switch, a release switch, a photographing mode switch, and a zoom switch. When the user presses the power switch, power is supplied from the battery (not shown) to the various circuits of the photographing apparatus 1 through the power line. After supplying power, a CPU (Central Processing Unit) 31 accesses a predetermined memory area (not shown), reads out a control program, loads it into the work area, and executes the loaded control program, whereby the entire photographing apparatus 1 is executed. Control.

  The CPU 31 drives and controls the aperture 13 via the aperture drive circuit 22 so that an appropriate exposure is obtained based on a photometric value measured by a photometric sensor 26 such as a TTL (Through The Lens) exposure meter. The state display device 33 (for example, LCD (Liquid Crystal Display)) displays the shooting mode, the appropriate exposure time at that time, the F value, and the like.

  When the release switch is pressed halfway, the CPU 31 determines the position and positional relationship between the photographing lens 11 and the photographing lens 12 on the optical axis AX via the lens control circuit 21 based on the detection result of the AF (Autofocus) sensor 25. Control. Thereby, the focus state of the photographic lens system 10 is adjusted. Next, when the release switch is fully pressed, the CPU 31 controls the drive of the focal plane shutter 15 via the shutter drive circuit 24 and causes the mirror 14 to return quickly. That is, the CPU 31 raises the mirror 14 via the mirror driving circuit 23 only during a period immediately before the front curtain travel of the focal plane shutter 15 starts and immediately after the rear curtain travel ends, so that the optical axis AX of the photographing lens system 10 is increased. The mirror 14 is retracted from the parallel optical path.

  The subject luminous flux that has passed through the photographic lens system 10 is imaged on the imaging surface of the solid-state imaging device 16 while the focal plane shutter 15 is open. The solid-state imaging device 16 is, for example, a CCD image sensor or a CMOS image sensor, and accumulates an optical image formed by each pixel on the imaging surface as a charge corresponding to the amount of light. The solid-state imaging device 16 converts the accumulated charge into a voltage (herein referred to as “pixel signal”) with a floating diffusion amplifier, and outputs the converted pixel signal to the A / D conversion circuit 27. The A / D conversion circuit 27 performs A / D conversion on the input pixel signal and outputs it to a DSP (Digital Signal Processor) 41.

  The DSP 41 controls the charge accumulation operation and the pixel signal readout operation of the solid-state imaging device 16 and performs predetermined signal processing on the pixel signal input from the A / D conversion circuit 27. Specifically, the DSP 41 performs predetermined signal processing such as color interpolation, matrix calculation, and Y / C separation on the pixel signal input from the A / D conversion circuit 27 to perform luminance signal Y, color difference signal Cb, Cr is generated and compressed in a predetermined format such as JPEG (Joint Photographic Experts Group). For example, the buffer memory 42 is used as a temporary storage location for processing data when the DSP 41 executes processing.

  A memory card 50 is detachably loaded in the card slot of the card interface 43. The DSP 41 can communicate with the memory card 50 via the card interface 43. The DSP 41 stores the generated compressed image signal (photographed image data) in the memory card 50 (or a built-in memory (not shown) provided in the photographing apparatus 1).

  Further, the DSP 41 performs predetermined signal processing on the signal after Y / C separation, and buffers it in a frame memory (not shown) in units of frames. The DSP 41 sweeps the buffered signal from each frame memory at a predetermined timing, converts it into a video signal of a predetermined format, and outputs it to the LCD control circuit 45 via the monitor interface 44. The LCD control circuit 45 modulates the liquid crystal based on the captured image data input from the DSP 41 and controls the backlight 47 to emit light. Thereby, the photographed image of the subject is displayed on the display screen of the LCD 46. The user can view a real-time through image with a proper brightness photographed with a proper focus through the display screen of the LCD 46.

[Pixel arrangement on the imaging surface]
FIG. 2A is a diagram schematically illustrating the configuration of the imaging surface of the solid-state imaging device 16. As shown in FIG. 2A, an effective pixel region 16A, an OB pixel region 16B, and a dummy pixel region 16C are formed on the imaging surface of the solid-state imaging device 16.

  The effective pixel area 16A is an area for forming an image of a photographed subject, and a plurality of effective pixels including a photoelectric conversion element that electrically accumulates information on the subject and outputs a signal is arranged.

  The OB pixel area 16B is an area in which a plurality of light-blocking films (for example, aluminum light-blocking films) coated on the same structure as the effective pixels arranged in the effective pixel area 16A (OB pixels) are arranged. It is arranged outside the effective pixel region so as not to appear as a black dot. In the present embodiment, the OB pixel region 16B is a region that surrounds the four sides of the rectangular effective pixel region 16A, but in another embodiment, only one side, only two sides, or three sides of the effective pixel region 16A. It may be a region that touches only.

  The OB pixel has the same photoelectric conversion element as the effective pixel. Therefore, the pixel signal output from the OB pixel (hereinafter referred to as “OB pixel signal”) depends on the sensitivity, shooting temperature, exposure time, and the like. The dark current component equivalent to "." Is included. For example, the average level of the OB pixel signal included in at least a part of the OB pixel region 16B is calculated as an OB detection value (reference black level signal) by a clamp circuit (not shown). The clamp circuit clamps the OB detection value as a black level, and subtracts an effective pixel signal from the clamped black level, thereby suppressing variations in black level offset components caused by dark current between frames and fields. be able to.

  Note that the output of each pixel is reset once read. Therefore, in order to obtain information on dark current components equivalent to effective pixels, OB pixels are required as physical means. Here, the variation of the OB detection value (reference black level signal) with respect to the true value of the black level is determined by the noise amount of the OB pixel and the number of samples. Therefore, in order to reduce the variation in the OB detection value (reference black level signal), it is desirable to increase the number of OB pixels. However, the number of OB pixels cannot be easily increased in order to meet the demand for downsizing the solid-state imaging device and increasing the effective pixel area.

  The dummy pixel region 16C is a region where a plurality of dummy pixels having no photoelectric conversion elements are arranged, and in this embodiment, the dummy pixel region 16C is arranged outside the OB pixel region 16B. In the present embodiment, a pixel signal output from a dummy pixel (hereinafter referred to as “dummy pixel signal”) is used in order to suppress variations in the black level detection value (reference black level signal).

[Image generation processing]
Next, an image generation process including a process of correcting the black level based on the detection value (reference black level signal) with suppressed variation will be described. FIG. 3 is a diagram illustrating a flowchart of image generation processing by the imaging apparatus 1 according to an embodiment of the present invention. The image generation process shown in FIG. 3 is started when the release switch is fully pressed, for example.

[S11 in FIG. 3 (Start of Exposure)]
In this processing step S11, exposure of the solid-state imaging device 16 is started under the set conditions. Conditions to be set include, for example, exposure time, F value, ISO sensitivity, and the like. These conditions are set automatically according to the AE (Automatic Exposure) program or according to the operation of the operation member 32 by the user.

[S12 in FIG. 3 (End of Exposure)]
In this process step S12, the exposure of the solid-state imaging device 16 under the set conditions is completed.

[S13 in FIG. 3 (Determination of Shooting Conditions)]
In this processing step S13, it is determined whether or not a predetermined photographing condition is satisfied. The imaging conditions determined here include, for example, at least one of the following three conditions.
The ISO sensitivity set for the solid-state image sensor 16 exceeds a predetermined sensitivity.
The photographing temperature of the solid-state image sensor 16 exceeds a predetermined temperature.
The exposure time of the solid-state image sensor 16 exceeds a predetermined time.

  The photographing temperature of the solid-state image sensor 16 is detected based on the output level of the temperature sensor 28 attached to the substrate of the solid-state image sensor 16. Note that the temperature sensor 28 may be incorporated in the solid-state imaging device 16.

[S14 in FIG. 3 (Ob detection value acquisition)]
This process step S14 is executed when it is determined in process step S13 (determination of shooting conditions) that a predetermined shooting condition is not satisfied (S13: NO).

  In this processing step S14, in order to preferentially suppress the variation in the black level offset component caused by the dark current over the variation in the black level detection value (reference black level signal), a dark current component equivalent to the effective pixel signal is generated. An OB detection value (reference black level signal) is acquired based on the included OB pixel signal. For example, when an OB pixel signal included in at least a part of the OB pixel region 16B is A / D converted by the A / D conversion circuit 27, the signal is buffered in the buffer memory. Next, an average value of these buffered OB pixel signals is calculated, and the calculated average value is obtained as an OB detection value (reference black level signal). Instead of the average value of the OB pixel signal, one representative value obtained from the OB pixel signal included in at least a part of the OB pixel region 16B may be used as the OB detection value (reference black level signal).

[S15 in FIG. 3 (Dummy Detection Value Acquisition)]
This processing step S15 is executed when it is determined in processing step S13 (determination of imaging conditions) that a predetermined imaging condition is satisfied (S13: YES).

  In this processing step S15, each dummy pixel by the A / D conversion circuit 27 is used in order to suppress the variation in the black level detection value (reference black level signal) over the variation in the black level offset component due to the dark current. The number of A / D conversions of the signal is set to a predetermined number (two or more times). Thus, the A / D conversion circuit 27 performs A / D conversion a plurality of times for each dummy pixel signal input from the solid-state imaging device 16. Note that A / D conversion for other pixels is performed once as usual. The dummy pixel signals for each time subjected to A / D conversion a plurality of times are buffered in the buffer memory 42. Next, a predetermined reference value (average value here) is calculated based on the buffered dummy pixel signals for a plurality of times, and the calculated average value is acquired as a dummy detection value (reference black level signal). Note that the average value may be calculated using only some of the dummy pixel signals in the buffer, instead of all the buffered dummy pixel signals for a plurality of times.

  FIG. 2B is a diagram conceptually showing each readout line of the solid-state imaging device 16. As shown in FIG. 2B, in this processing step S15, the dummy pixel lines are artificially increased by reading the dummy pixel lines a plurality of times (by performing A / D conversion a plurality of times). . In other words, since the number of dummy pixel samples is artificially increased, the calculation accuracy of the dummy detection value (reference black level signal) is improved without increasing the size of the solid-state imaging device or reducing the area of the effective pixel area. To do.

  Supplementally, the dummy pixel signal does not include noise derived from the photoelectric conversion element because the dummy pixel does not have the photoelectric conversion element. Therefore, there is less noise than the OB pixel signal, and this point also contributes to improving the calculation accuracy of the dummy detection value (reference black level signal).

  Since the dark pixel component is not included in the dummy pixel signal, the dark current component included in the effective pixel signal cannot be removed with the dummy detection value (reference black level signal) as it is. Therefore, in this embodiment, the dark current component included in the effective pixel signal is estimated from shooting conditions such as shooting temperature and exposure time, and the estimated dark current component is added to the dummy detection value (reference black level signal). Thus, the reference black level signal is corrected. Thereby, an appropriate reference black level signal is acquired. As an estimation method of the dark current component, for example, the dark current component obtained in the adjustment process and the shooting conditions (sensitivity, temperature, exposure time, etc.) at that time are stored in the memory, and shooting at the time of shooting is performed. One in which the dark current component is estimated from the ratio between the conditions and the photographing conditions at the adjustment step is mentioned.

  Further, an offset component for each individual is potentially included in addition to the dark current component between the effective pixel signal and the dummy pixel signal. This type of offset component information is acquired in advance, and is held in a memory (not shown) at the time of factory shipment, for example. After the calculation of the dummy detection value (reference black level signal), the information of the offset component held in the memory is read, and the offset component contained in the dummy detection value (reference black level signal) is removed.

[S16 in FIG. 3 (correction of effective pixel signal)]
In this processing step S16, the black level of the effective pixel signal is corrected based on the reference black level signal acquired in processing step S14 (obtain OB detection value) or processing step S15 (acquisition of dummy detection value).

[S17 in FIG. 3 (Generation and Storage of Captured Image Data)]
In this processing step S17, captured image data is generated based on the effective pixel signal after the black level correction, and the generated captured image data is stored in the memory card 50 (or a built-in memory (not shown) provided in the imaging apparatus 1). Is done.

  FIG. 4 is a diagram illustrating a driving sequence at the time of photographing by the photographing apparatus 1. 4A shows the operation timing of the focal plane shutter 15, FIG. 4B shows the timing of VD (Vertical Driving pulse), and FIGS. 4C to 4F show the readout of each pixel. Indicates timing.

  FIG. 4C shows the readout timing of each pixel at the time of executing the processing step S14 (obtain OB detection value) of FIG. As shown in FIG. 4C, at the time of execution of the processing step S14 (obtain OB detection value), the number of read rows of dummy pixels is changed from the initially set number of read rows to the minimum number of rows that can be set. Is set. Here, since the 0th row is set, readout of the dummy pixel signal (A / D conversion) is not performed. Specifically, when the trailing curtain travel is completed and the focal plane shutter 15 is closed, the dummy pixel readout row is set to 0, and then the OB pixel signal and the effective pixel signal are sequentially read out. In the example of FIG. 4C, the total readout time is shortened because the dummy pixel signal is not read out.

  FIG. 4D shows the readout timing of each pixel at the time of executing the processing step S15 (acquisition of dummy detection values) in FIG. As shown in FIG. 4D, when the processing step S15 (acquisition of dummy detection value) is executed, the number of read rows of the OB pixel is changed from the initially set number of read rows to the minimum settable number of rows. Is set. Here, since the 0th row is set, reading of the OB pixel signal (A / D conversion) is not performed. Specifically, when the trailing curtain travel is finished and the focal plane shutter 15 is closed, a dummy pixel signal is read out, and then, when the OB pixel readout line is set to 0, the effective pixel signal is finally output. Is read out. Also in the example of FIG. 4D, since the OB pixel signal is not read, the total reading time is shortened.

  FIG. 4 (e) shows a modification of FIG. 4 (d). Since the dummy pixel does not have a photoelectric conversion element, it is not exposed to light even when the focal plane shutter 15 is open. Therefore, the dummy pixel signal can be read even when the focal plane shutter 15 is open, such as during continuous shooting.

  Therefore, in the example of FIG. 4E, the reading of the dummy pixel signal is started before the focal plane shutter 15 is fully closed. That is, before the focal plane shutter 15 is fully closed, at least some of the dummy pixels in the dummy pixel region 16C are read out. This shortens the time from when the focal plane shutter 15 is closed until the reading of the effective pixel signal is completed. By shortening the time, for example, the number of frames that can be continuously shot can be increased.

  FIG. 4F shows a modification of FIG. When the effective pixel signal is read after the dummy pixel signal, the output around the circuit such as the solid-state imaging device 16 may float due to heat generated during the reading operation, and the pixel value of the effective pixel signal may float. As a result, the image quality may be deteriorated.

  Therefore, in the example of FIG. 4F, the effective pixel signal is read before the dummy pixel signal. Thereby, the floating of the pixel value of the effective pixel signal due to heat generation is suppressed, and the deterioration of the image quality due to the floating of the pixel value is suppressed.

  The above is the description of the exemplary embodiments of the present invention. Embodiments of the present invention are not limited to those described above, and various modifications are possible within the scope of the technical idea of the present invention. For example, the embodiment of the present application also includes an embodiment that is exemplarily specified in the specification or a combination of obvious embodiments and the like as appropriate.

DESCRIPTION OF SYMBOLS 1 Shooting device 10 Shooting lens system 11, 12 Shooting lens 13 Diaphragm 14 Mirror 15 Focal plane shutter 16 Imaging element 17 Penta prism 18 Diffusion plate 19 Eyepiece 21 Lens control circuit 22 Diaphragm drive circuit 23 Mirror drive circuit 24 Shutter drive circuit 25 AF Sensor 26 Photometric sensor 27 A / D conversion circuit 28 Temperature sensor 31 CPU
32 Operation member 33 Status display device 41 DSP
42 Buffer memory 43 Card interface 44 Monitor interface 45 LCD control circuit 46 LCD
47 Backlight 50 Memory card

Claims (8)

A solid-state image sensor having a plurality of dummy pixels not having a photoelectric conversion element;
The number of times of reading out each dummy pixel is set to a plurality of times according to shooting conditions, and the solid-state imaging device is based on at least a part of signals of each dummy pixel read out for the set number of times. Acquisition means for acquiring a reference black level signal for correcting the black level of the effective pixels of
Comprising
Shooting device. The acquisition means includes
The signal output from each dummy pixel is A / D converted a set number of times,
A predetermined reference value is calculated based on A / D converted signals for a plurality of times,
Obtaining the calculated reference value as the reference black level signal;
The imaging device according to claim 1. Estimating means for estimating a dark current component included in the output signal of the effective pixel;
Correction means for correcting the reference black level signal acquired based on each dummy pixel based on the estimated dark current component;
Comprising
The imaging device according to claim 1 or 2. A mechanical shutter for controlling the amount of light incident on the solid-state image sensor;
The acquisition means includes
Reading at least part of each of the dummy pixels during a period when the mechanical shutter is open,
The imaging device according to any one of claims 1 to 3. The acquisition means includes
Reading each dummy pixel after reading all effective pixels of the solid-state imaging device,
The imaging device according to any one of claims 1 to 3. The solid-state imaging device is
It has multiple optical black pixels,
The acquisition means includes
When the shooting condition satisfies a predetermined condition, the reference black level signal is acquired based on each dummy pixel,
When the shooting condition does not satisfy a predetermined condition, instead of the signal of each dummy pixel, the signal of each optical black pixel is read, and the reference black level signal is based on the read signal of each optical black pixel To get the
The imaging device according to any one of claims 1 to 5. The predetermined condition is:
ISO sensitivity set for the solid-state imaging device exceeds a predetermined sensitivity,
The shooting temperature of the solid-state imaging device exceeds a predetermined temperature,
The exposure time of the solid-state image sensor exceeds a predetermined time,
Including at least one of
The imaging device according to claim 6. The acquisition means includes
When reading the signal of each dummy pixel, the number of read lines of each optical black pixel is reduced from the initially set number of read lines,
When reading the signal of each optical black pixel, the number of read rows of each dummy pixel is reduced from the initially set number of read rows.
The imaging device according to claim 6 or 7.

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