JP6506937B2 - Imaging device - Google Patents

Description

  The present invention relates to an imaging device that performs imaging in an environment in which illumination blinks.

  In general, an image pickup element which picks up a moving image performs light detection by a photodiode, accumulates generated signal charges, and periodically reads out the signal charge. On the other hand, illuminations such as fluorescent lamps and mercury lamps repeat flickering at twice the frequency of the AC power supply, and a phenomenon called flicker occurs in which the brightness of the captured image fluctuates due to the difference in frequency between the two. .

  A conventional imaging camera is provided with a function called an electronic shutter in order to suppress this flicker. This electronic shutter function suppresses flicker by limiting the accumulation time of the signal charge to an integral multiple of the flashing cycle of the illumination. However, in the conventional electronic shutter function, when the frame frequency of the imaging camera becomes higher than the blinking frequency of the illumination, the blinking period of the illumination exceeds one frame period, and the flicker can not be suppressed. In particular, since the photographing frequency for super hi-vision is high at a frame frequency of 120 Hz, there is a concern about an increase in flicker.

  Then, the invention of patent document 1 is proposed. The invention described in Patent Document 1 determines the average value of the signals read by each of the first scanning pulse and the second scanning pulse, so that the variation of the signal output value that is several times or more is several tens of percent. It reduces to an extent and reduces flicker.

Unexamined-Japanese-Patent No. 7-281021 gazette

However, according to the invention described in Patent Document 1, the signal output value has a variation of about several tens of percent, and flicker may remain.
Then, this invention makes it a subject to provide an imaging device which flicker does not generate | occur | produce.

In view of the problems described above, an imaging device according to the present invention is an imaging device that performs imaging in an environment in which the flickering frequency k of the illumination and the frame frequency f satisfy f / 2 <k <f. A light detection pause period for pausing light detection is provided with a length L = 1 / k−1 / f at the center of the signal readout period of the signal detection period, and the light detection period excluding the light detection pause period in the signal read period. The imaging unit includes an imaging unit that includes a rolling shutter that performs light detection for each scanning line, and is configured of a 4-transistor pixel having a photodiode, and includes two times of light detection included in a signal readout period. AD conversion means for reading out an electrical signal from the photodiode in a period and performing AD conversion on the electrical signal read out in the first and second light detection periods, and the first and second light detection For between, characterized in that it comprises, adding means for adding the electrical signals converted by the AD converter in the AD converter.

  According to this configuration, in the imaging device, of the flickering waveforms of the illumination included in one frame period (signal readout period), the flickering waveform of the illumination included in the light detection period is vertically symmetrical with respect to the average value. Therefore, in the imaging device, the adverse effect due to the flashing of the illumination is eliminated.

  In the imaging device according to the present invention, since the adverse effect due to the flickering of the illumination is canceled, flicker does not occur, and an easy-to-see image can be taken.

FIG. 2 is an explanatory view for explaining the principle of the present invention, and shows a relationship between a signal readout period, a light detection period, and a light detection pause period. It is explanatory drawing explaining the principle of this invention, and represents the relationship between a flame | frame period, the blink period of illumination, and a light detection rest period. It is explanatory drawing explaining the principle of this invention, and represents the relationship between a flame | frame period, the blink period of illumination, and a light detection rest period. It is a schematic block diagram of the imaging device concerning a 1st embodiment of the present invention. It is a timing chart of an imaging device of Drawing 4, and (a) expresses the opening and closing timing of a mechanical shutter, and (b) expresses a light detection rest period. It is a schematic block diagram of the imaging device concerning a 2nd embodiment of the present invention. It is a timing chart of an imaging device of Drawing 6, and (a) expresses a signal read-out cycle of each line of an image sensor, and (b) expresses time of each frame picture. It is a schematic block diagram of the imaging device concerning a 3rd embodiment of the present invention. FIG. 9 is a timing chart of the imaging device of FIG. 8, in which (a) represents a light detection pause period, (b) represents an ON state / OFF state of each transistor, and (c) represents an AD conversion interval. FIG. 9 is a timing chart of the imaging device of FIG. 8, where (a) represents the readout timing of the first pixel, (b) represents the readout timing of the m th pixel, and (c) represents the AD conversion interval. Represent. It is a schematic block diagram of the imaging device concerning a 4th embodiment of the present invention. FIG. 12 is a timing chart of the imaging device of FIG. 11, in which (a) represents a light detection pause period, (b) represents an ON state / OFF state of each transistor, and (c) represents an AD conversion interval.

(Principle of the present invention)
Before describing the embodiments of the present invention, the principle of the present invention will be described with reference to FIGS. 1 to 3.
Here, the frame frequency is f (Hz), and the flickering frequency of the light is k (Hz). In addition, the illumination blinks according to a waveform in which sine waves of a frequency k (Hz) and its odd multiple frequency are superimposed.

The signal readout period in FIG. 1 is a period during which an electrical signal is read out from the imaging device in order to generate one frame image. This signal readout period has the same length as the frame period 1 / f (seconds).
The light detection pause period is a period during which no electrical signal is generated by light detection in the signal readout period. In FIG. 1, the light detection pause period is illustrated by dots in the signal readout period.
The light detection period is a period in which an electric signal is generated by light detection in the signal readout period.
In the light detection, the image sensor photoelectrically converts the received light to generate an electric signal.

As shown in FIG. 1, a light detection pause period of a length L (seconds) represented by the following equation (1) is provided around the center time of the signal readout cycle. That is, the frame images n, n + 1,... Are generated by the electric signal of the light detection period excluding the light detection pause period in the signal readout period (n is a natural number of 2 or more).
L = 1 / k−1 / f formula (1)

In the example of FIG. 2, the frame period is 1/120 (seconds), and the blinking period of the illumination is 1/100 (seconds). Therefore, the light detection pause period is 1/600 (seconds). Here, since f / 2 <k <f is satisfied, among the flickering waveforms of illumination included in one frame cycle (signal readout cycle), the flickering waveforms included in the light detection period are vertically symmetrical with respect to the average value. Repeated. In other words, in each frame period, the area areas α1 and α2 surrounded by the blinking waveform and the average value become equal above and below the average value. For this reason, the adverse effect due to the blinking of the light disappears, and flicker does not occur.
In FIG. 2, the area areas α1 and α2 are illustrated by hatching.

  Here, as shown in FIG. 3, the frame period is insufficient at the lower right portion of the circle with respect to the blinking period of the illumination. Since the short period of the frame period causes flicker, on the other side of the center C of the circle, a balanced light detection pause period is provided for this short period.

  This insufficient period appears not only in the flickering frequency k of the light but also in the frequencies 2k, 4k, ... and odd frequencies 3k, 5k, ... of even multiples, but according to the principle of the present invention, the odd multiples It can be removed only with frequency components. And the waveform which piled up the blink frequency k, 3k, 5k, ... of illumination can be expressed also with rectangular waves or triangular waves other than a sine wave. Therefore, according to the principle of the present invention, even if the flickering waveform of the illumination is other than the sine wave, the flicker does not occur.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each embodiment, means having the same function are denoted by the same reference numeral, and the description thereof is omitted.

First Embodiment
[Configuration of Imaging Device]
The configuration of the imaging device 1 according to the first embodiment of the present invention will be described with reference to FIG.
As illustrated in FIG. 4, the imaging device 1 is an imaging camera (for example, a broadcast camera) that captures a moving image of a subject, and includes an imaging optical system 10, a mechanical shutter 12, and an imaging element (imaging unit) 14. A shutter drive circuit 16 and an imaging device drive circuit 18 are provided.

  The imaging optical system 10 is a lens group including a plurality of lenses including an objective lens, and emits light from a subject toward the mechanical shutter 12. The imaging optical system 10 has a general configuration that is not directly related to the present invention, and thus further description will be omitted. Further, in FIG. 4, the imaging optical system 10 is illustrated as one lens in order to make the drawing easy to see.

  The mechanical shutter 12 is a mechanical shutter disposed on the optical axis of the imaging optical system 10. The mechanical shutter 12 opens and closes in accordance with a shutter drive signal input from the shutter drive circuit 16. Here, when the mechanical shutter 12 is open, light from the imaging optical system 10 enters the imaging element 14. On the other hand, when the mechanical shutter 12 is closed, the light from the imaging optical system 10 is blocked by the mechanical shutter 12 and does not enter the imaging element 14.

The imaging device 14 receives incident light that has passed through the mechanical shutter 12 and generates an image signal from the received incident light. For example, a charge coupled device (CCD) sensor or a complementary metal oxide semiconductor (CMOS) sensor provided with a global shutter can be given as the imaging device 14.
Here, the global shutter is one in which all pixels simultaneously start and end light detection.

  The shutter drive circuit 16 shields the light during the light detection pause period, and drives the mechanical shutter 12 so as to pass the light during the light detection period. The shutter drive circuit 16 outputs a shutter drive signal for opening and closing the mechanical shutter 12 to the mechanical shutter 12 in synchronization with the image sensor drive signal input from the image sensor drive circuit 18.

  The imaging device drive circuit 18 drives the imaging device 14. The imaging device drive circuit 18 outputs an imaging device drive signal (timing pulse) indicating the drive timing of the imaging device 14 to the imaging device 14 and the shutter drive circuit 16.

[Relationship between opening and closing of mechanical shutter and light detection pause period]
The relationship between the opening and closing of the mechanical shutter 12 and the light detection pause period will be described with reference to FIG. 5 (see FIG. 4 as needed).

  As shown in FIG. 5, the shutter drive circuit 16 drives the mechanical shutter 12 to open in the light detection period in synchronization with the image pickup device drive signal to pass the light from the image pickup optical system 10 to the image pickup device 14. . Further, the shutter drive circuit 16 drives the mechanical shutter 12 to close in the light detection pause period in synchronization with the image pickup device drive signal, and cuts off the light from the image pickup optical system 10.

  As described above, the imaging device 1 can realize the light detection pattern of FIG. 2 by driving the mechanical shutter 12 by the shutter drive circuit 16 in accordance with the light detection period and the light detection pause period. Therefore, the imaging device 1 can capture an easy-to-see image without flicker.

Second Embodiment
The configuration of an imaging device 1B according to a second embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 6, the imaging apparatus 1B is an imaging camera for capturing a moving image of a subject, and includes an imaging optical system 10, a mechanical shutter 22, an imaging element (imaging means) 24, a shutter drive circuit 26, and imaging And an element drive circuit 28.

  The mechanical shutter 22 is a mechanical shutter that is disposed on the optical axis of the imaging optical system 10 and can shield light for each line (scanning line) of the imaging device 24. The mechanical shutter 22 opens and closes in line units of the image sensor 24 in accordance with a shutter drive signal from the shutter drive circuit 26.

  The image sensor 24 receives incident light that has passed through the mechanical shutter 22 and generates an image signal from the received incident light. For example, as the imaging device 24, a CMOS sensor provided with a rolling shutter (line exposure sequential readout) can be mentioned.

  Here, the rolling shutter is to start and end light detection sequentially for each line of the imaging device 24. That is, in the imaging device 24, the timing of the signal readout cycle (vertical scan) differs in each line.

  The shutter drive circuit 26 blocks the light during the light detection pause period, and drives the mechanical shutter 22 so as to pass the light during the light detection period. The shutter drive circuit 26 outputs a shutter drive signal for opening and closing the mechanical shutter 22 to the mechanical shutter 22 in synchronization with the image sensor drive signal input from the image sensor drive circuit 28.

  The imaging device drive circuit 28 drives the imaging device 24 line by line. The imaging device drive circuit 28 outputs an imaging device drive signal (timing pulse) representing a drive timing for each line of the imaging device 24 to the imaging device 24 and the shutter drive circuit 26.

[Relationship between opening and closing of mechanical shutter and light detection pause period]
The relationship between the opening and closing of the mechanical shutter 22 and the light detection pause period will be described with reference to FIG. 7 (see FIG. 6 as needed).

  As shown in FIG. 7, the image sensor 24 performs signal readout in the order of lines 1, 2,..., M−1, m (m is a natural number of 2 or more). That is, in the imaging element 24, the signal readout periods of the lines 1, 2, ..., m-1, m are shifted. Therefore, the shutter drive circuit 26 drives the mechanical shutter 12 so as to open during the light detection period of the lines 1, 2, ..., m-1, m. Accordingly, the light from the imaging optical system 10 is incident on the lines 1, 2,..., M−1, m of the imaging device 14.

  Further, the shutter drive circuit 26 drives the mechanical shutter 22 to close in the light detection pause period of the lines 1, 2, ..., m-1, m. Therefore, the light from the imaging optical system 10 is shielded by the mechanical shutter 22.

  As described above, the imaging device 1B synchronizes with the imaging element drive signal in synchronization with the imaging element drive signal in accordance with the light detection period and the light detection pause period of the lines 1, 2, ..., m-1, m by the shutter drive circuit 26. By driving 22, the light detection pattern of FIG. 2 can be realized. Therefore, the imaging device 1B can capture an easy-to-see image without flicker.

Third Embodiment
[Configuration of imaging device]
The configuration of an imaging device (imaging unit) 30 provided in an imaging device 1C according to a third embodiment of the present invention will be described with reference to FIGS. 8 and 9.
For example, general configurations not directly related to the present invention, such as a vertical scanning circuit, a horizontal scanning circuit, and a CDS (Correlated Double. Sampling) circuit, are omitted.

  The imaging element 30 receives incident light via an imaging optical system (not shown) of the imaging device 1C, and generates a video signal from the received incident light. For example, the imaging device 30 is a CMOS sensor provided with a rolling shutter. Further, as shown in FIGS. 8 and 9, the imaging device 30 includes the pixel 32, the vertical signal line 34, an ADC (Analog to Digital Converter: AD conversion means) 36, and an adder (addition means) 38. .

The pixel 32 is a four-transistor pixel, and generates an electrical signal of a voltage according to the intensity of the received incident light. The pixels 32 are arranged in the matrix direction (horizontal direction and vertical direction), and each of the pixels 32 is connected to the vertical signal line 34. Then, the pixel 32 outputs the generated electrical signal to the vertical signal line 34.
The specific structure of the pixel 32 will be described later.

The vertical signal line 34 outputs the electrical signal input from the pixel 32 to the ADC 36 via a horizontal signal line (not shown).
The ADC 36 performs AD conversion on the electrical signal input from the pixel 32 and outputs the same to the adder 38.
The adder 38 adds the electrical signals AD-converted by the ADC 36 to generate a video signal.

[Specific structure of pixel]
The specific structure of the pixel 32 will be described with reference to FIG.
As shown in FIG. 8, the pixel 32 includes a photodiode PD, a readout transistor TX, a floating diffusion region FD, a reset transistor RT, an amplification transistor AP, and a selection transistor SL.

  The photodiode PD is a diode having a photoelectric conversion function and a charge storage function. The photodiode PD photoelectrically converts the signal charge into an amount corresponding to the intensity of incident light, and stores the signal charge. The cathode of the photodiode PD is connected to the source of the read transistor TX.

  The readout transistor TX reads out the signal charge of the photodiode PD and transfers the signal charge to the floating diffusion region FD when a signal is input to the gate to be turned on. The gate of the read transistor TX is connected to a horizontal selection line (not shown), and the drain is connected to the floating diffusion region FD.

  The floating diffusion region FD temporarily accumulates the signal charge from the read transistor TX. The floating diffusion region FD generates an electrical signal of a voltage corresponding to the amount of signal charge temporarily accumulated. The floating diffusion region FD is connected to the source of the reset transistor RT and the gate of the amplification transistor AP.

  The reset transistor RT resets the potential of the floating diffusion region FD when it is turned on. In the reset transistor RT, a control signal for switching between the ON state and the OFF state is input to the gate, and the drain is connected to the reset power supply VRT.

  The amplification transistor AP amplifies the electric signal generated in the floating diffusion region FD. The source of the amplification transistor AP is connected to the drain of the selection transistor SL, and the drain is connected to the drain power supply VDD.

  The selection transistor SL outputs the electric signal amplified by the amplification transistor AP to the vertical signal line 34 when the selection transistor SL is turned on. In the selection transistor SL, a control signal for switching between the ON state and the OFF state is input to the gate, and the drain is connected to the vertical signal line 34.

[Relationship between driving of transistor and light detection idle period]
The relationship between the driving of the transistor and the light detection idle period will be described with reference to FIG.
FIG. 9 is a timing chart of one pixel 32 among the m pixels 32 arrayed in the vertical direction. In FIG. 9, times t0 to t4 are illustrated on the time axis. Further, in the middle part of FIG. 9, the ON state of each transistor is illustrated by a dot rectangle.

  As shown in FIG. 9, the photodiode PD accumulates signal charges in the light detection period from time t0 to t1. At time t1, the read transistor TX and the select transistor SL are turned on. Then, the signal charge stored in the photodiode PD is transferred to the floating diffusion region FD, and then output to the ADC 36 as an electrical signal through the vertical signal line 34.

  In order to reliably prevent the saturation of the floating diffusion region FD, the reset transistor RT is turned on in the middle of time t1 to t2. Then, the signal charge of the floating diffusion region FD is reset.

  The photodiode PD accumulates the signal charge also during the light detection pause period from time t1 to t2. Therefore, at time t2, the read transistor TX is turned on, and immediately thereafter, the reset transistor RT is turned on. Then, the signal charge stored in the photodiode PD is reset after being transferred to the floating diffusion region FD.

  At time t2, when the read transistor TX and the reset transistor RT are simultaneously turned on, the potential of the reset power supply VRT may be applied to the photodiode PD, which may cause an adverse effect such as noise. Therefore, the timing at which the reset transistor RT is turned on is slightly delayed from that of the read transistor TX.

  During the light detection period from time t2 to t3, the photodiode PD accumulates the signal charge. At time t3, the read transistor TX and the select transistor SL are turned on, and immediately thereafter, the reset transistor RT is also turned on. Then, the signal charge stored in the photodiode PD is transferred to the floating diffusion region FD and then output to the vertical signal line 34. The signal is output to the ADC 36 as an electrical signal through the vertical signal line 34.

  The electrical signals at time t0 to t1 and time t2 to t3 are AD converted by the ADC 36 and output to the adder 38. Then, the electric signals at time t0 to t1 and time t2 to t3 are added by the adder 38 and generated as a video signal.

In practice, the imaging device 1C is provided with m vertically arranged pixels ₃₂ 1 to 32 _m. The pixels 32 _{1 to} 32 _m are connected to the same ADC 36 via the vertical signal line 34, and the readout timing is different as shown in FIG. 10. Therefore, in order to generate the video signal of the same frame, the ADC 36 performs AD conversion m times while shifting the timing. At this time, the ADC 36 needs to AD convert the electrical signals output from the pixels 32 _{1 to} 32 _m from time t ₁ of the pixel 321 to time t ₁ of the pixel 32 _m .

  The ADC 36 can not continuously AD convert the electric signals at time t0 to t1 and time t2 to t3. For this reason, the interval which AD-converts the electric signal of time t0-t1 and time t2-t3 will open (blank period).

As described above, the imaging apparatus 1C divides the light signal into two light detection periods with the light detection pause period as a boundary, reads out the light signals, and adds the electric signals in each light detection period to form the light detection pattern of FIG. Can be realized. Therefore, the imaging device 1C can capture an easy-to-see image without flicker.
Furthermore, in the imaging device 1C, since the imaging device 30 is configured by four transistor pixels, the imaging device 30 can be simplified as compared to the five-transistor pixel in FIG.

Fourth Embodiment
[Configuration of imaging device]
The configuration of an imaging device (imaging unit) 40 provided in an imaging device 1D according to a fourth embodiment of the present invention will be described with reference to FIGS. 11 and 12.
As in FIG. 8, general configurations not directly related to the present invention are omitted.

  The imaging device 40 receives incident light via an imaging optical system (not shown) of the imaging device 1D, and generates a video signal from the received incident light. For example, the imaging device 40 is a CMOS sensor provided with a rolling shutter. Further, as shown in FIGS. 11 and 12, the imaging device 40 includes the pixel 42, the vertical signal line 34, the ADC 36, and the adder 38.

The pixel 42 is a five-transistor pixel, and generates an electrical signal of a voltage according to the intensity of the received incident light. Also, the pixels 42 are arranged in the matrix direction, and each is connected to the vertical signal line 34. Then, the pixel 42 outputs the generated electrical signal to the vertical signal line 34.
Note that, except for the pixel 42, the explanation is omitted because it is the same as the third embodiment.

[Specific structure of pixel unit]
The specific structure of the pixel 42 will be described with reference to FIG.
As shown in FIG. 11, the pixel 42 includes a photodiode PD, a first readout transistor TX1, a second readout transistor TX2, a floating diffusion region FD, a reset transistor RT, an amplification transistor AP, and a selection transistor SL. Prepare.
The components other than the first read transistor TX1 and the second read transistor TX2 are the same as those in the third embodiment, and thus the description thereof is omitted.

  The first read transistor TX1 reads a signal charge of the photodiode PD and transfers the signal charge to the second read transistor TX2 when a signal is input to the gate to be turned on. The gate of the first read transistor TX1 is connected to a horizontal selection line (not shown), the source is connected to the photodiode PD, and the drain is connected to the source of the second read transistor TX2.

  When the second read transistor TX2 is turned on, the signal charge of the second read transistor TX2 is transferred to the floating diffusion region FD. The gate of the second read transistor TX2 is connected to a horizontal selection line (not shown), and the drain is connected to the floating diffusion region FD.

[Relationship between driving of transistor and light detection idle period]
The relationship between the driving of the transistor and the light detection idle period will be described with reference to FIG.
FIG. 12 is a timing chart of one pixel 42 among the m pixels 42 arrayed in the vertical direction. In FIG. 12, times t0 to t5 are illustrated on the time axis. Further, in the middle part of FIG. 12, the ON state of each transistor is illustrated by a dot rectangle.

  As illustrated in FIG. 12, the photodiode PD accumulates signal charges in the light detection period from time t0 to t1. At time t1, the first read transistor TX1 is turned on. Then, the signal charge stored in the photodiode PD is transferred to the second read transistor TX2.

  Subsequently, at time t2, the second read transistor TX2 and the selection transistor SL are turned on. Then, the signal charge of the second readout transistor TX2 is transferred to the floating diffusion region FD, and then output to the ADC 36 as an electrical signal through the vertical signal line 34.

  The photodiode PD accumulates the signal charge also during the light detection pause period from time t1 to t3. Therefore, at time t3, the first read transistor TX1 is turned on, and immediately thereafter, the second read transistor TX2 is turned on. Further, immediately after the second read transistor TX2 is turned on, the reset transistor RT is also turned on. That is, the first read transistor TX1, the second read transistor TX2, and the reset transistor RT are sequentially turned on. Then, the signal charge stored in the photodiode PD is reset after being transferred to the floating diffusion region FD.

  If the first read transistor TX1 and the second read transistor TX2 are simultaneously turned on at time t3, charge transfer may be adversely affected. Therefore, the timing at which the second read transistor TX2 is turned ON is slightly delayed compared to the first read transistor TX1. Further, for the same reason as in the first embodiment, the timing at which the reset transistor RT is turned on is slightly delayed compared to the second read transistor TX2.

  During the light detection period from time t3 to time t4, the photodiode PD accumulates signal charge. At time t4, the first read transistor TX1 and the select transistor SL are turned on, and immediately thereafter, the second read transistor TX2 is turned on. Further, immediately after the second read transistor TX2 is turned on, the reset transistor RT is also turned on. Then, the signal charge stored in the photodiode PD is transferred to the floating diffusion region FD, and then output to the ADC 36 as an electrical signal through the vertical signal line 34.

Here, the electrical signals of time t0 to t1 and time t3 to t4 are AD converted by the ADC 36 and output to the adder 38. Then, the electric signals at time t0 to t1 and time t3 to t4 are added by the adder 38 and generated as a video signal.
Since the ADC 36 performs m AD conversions and is the same as the third embodiment, the description will be omitted.

  As described above, the imaging device 1D divides the light signal into two light detection periods with the light detection pause period as a boundary, reads out the light signals, and adds the electric signals in each light detection period to form the light detection pattern of FIG. Can be realized. Therefore, the imaging device 1D can capture an easy-to-see image without flicker.

  Furthermore, the imaging device 1D can use the second readout transistor TX2 as a buffer that temporarily accumulates the signal charge of the photodiode PD. For this reason, since the imaging device 1D does not have a blank period as shown in FIG. 10, the electric signals at time t0 to t1 and time t3 to t4 can be AD converted at long intervals. You can have it.

The present invention is not limited to the embodiments described above, and modifications can be made without departing from the scope of the invention.
In each of the above-described embodiments, the imaging device has been described as an example, but the imaging device according to the present invention can also use an imaging tube as an imaging means.

1, 1B, 1C, 1D Imaging device 10 Imaging optical system 12, 22 Mechanical shutters 14, 24, 30, 40 Imaging device (imaging means)
16, 26 shutter drive circuit 18, 28 image pickup element drive circuit 32, 42 pixel 34 vertical signal line 36 ADC (AD conversion means)
38 Adder (adding means)

Claims (2)

In an imaging apparatus that performs imaging in an environment where the flickering frequency k of the illumination and the frame frequency f satisfy f / 2 <k <f,
A light detection pause period for pausing light detection is provided with a length L = 1 / k−1 / f at the center of a signal readout cycle having the same length as one frame cycle, and the light detection pause in the signal readout cycle is provided. Imaging means for performing light detection in a light detection period excluding the period ;
The imaging means comprises a rolling shutter for performing light detection for each scanning line, and is comprised of a 4-transistor pixel having a photodiode.
Reading an electrical signal from the photodiode during two light detection periods included in the signal reading period;
AD conversion means for AD converting each of the electrical signals read out during the first and second light detection periods;
Addition means for adding the electric signal AD-converted by the AD conversion means for the first and second light detection periods;
An imaging apparatus comprising: In an imaging apparatus that performs imaging in an environment where the flickering frequency k of the illumination and the frame frequency f satisfy f / 2 <k <f,
A light detection pause period for pausing light detection is provided with a length L = 1 / k−1 / f at the center of a signal readout cycle having the same length as one frame cycle, and the light detection pause in the signal readout cycle is provided. Imaging means for performing light detection in a light detection period excluding the period;
The imaging means comprises a rolling shutter for performing light detection for each scanning line, and is comprised of a 5-transistor pixel having a photodiode.
Reading an electrical signal from the photodiode during two light detection periods included in the signal reading period;
AD conversion means for AD converting the electrical signals read out during the first and second light detection periods at equal intervals;
Addition means for adding the electric signal AD-converted by the AD conversion means for the first and second light detection periods;
An imaging apparatus comprising:

Images