Signal processing apparatus and method, imaging element, and electronic apparatus
The present disclosure relates to a signal processing apparatus and method, an imaging element, and an electronic apparatus capable of suppressing deterioration of subjective image quality. Driving of a shift register controlling transfer of pixel data of digital data obtained by A/D conversion is stopped in a part or the entirety of a period in which the A/D conversion is performed on a pixel output of an analog signal. The present disclosure can be applied to, for example, a signal processing apparatus, an imaging element, an imaging device, an image processing apparatus, an electronic apparatus, a signal processing method, a program, or the like.
1. A signal processing apparatus, comprising:
an A/D conversion unit configured to perform, in a first period, A/D conversion on a first pixel output of an analog signal to obtain digital data; and
a processor configured to stop drive of a shift register that controls transfer of the digital data,
wherein the drive of the shift register is stopped in one of a part or an entirety of the first period in which the A/D conversion is performed on the first pixel output of the analog signal.
2. The signal processing apparatus according to claim 1 , wherein the processor is further configured to stop the drive of the shift register from a start timing of the first period in which the A/D conversion is performed.
3. The signal processing apparatus according to claim 2 , wherein
the processor is further configured to stop the drive of the shift register in one of a part or an entirety of a second period and one of a part or an entirety of a third period,
in the second period, the A/D conversion unit is further configured to perform the A/D conversion on a second pixel output,
the second pixel output is in a reset period of correlated double sampling,
in the third period, the A/D conversion unit is further configured to perform the A/D conversion on a third pixel output, and
the third pixel output is in a signal readout period of the correlated double sampling.
4. The signal processing apparatus according to claim 3 , wherein the processor is further configured to:
stop the drive of the shift register in the entirety of the second period in which the A/D conversion is performed on the second pixel output in the reset period; and
stop the drive of the shift register in a fourth period longer than the second period in which the A/D conversion is performed on the second pixel output in the reset period,
wherein the fourth period is within the third period in which the A/D conversion is performed on the third pixel output in the signal readout period.
5. The signal processing apparatus according to claim 1 , wherein
the shift register further:
controls drive of each of a holding unit and a sense amplifier, and
controls the transfer of the digital data based on the control of the drive of the holding unit and the sense amplifier,
the holding unit holds the digital data, and
the sense amplifier converts the digital data read out from the holding unit from a current to a voltage.
6. The signal processing apparatus according to claim 5 , wherein the processor is further configured to:
stop supply of a shift register clock that drives the shift register;
stop the drive of the shift register based on the stop of the supply of the shift register clock;
restart the supply of the shift register clock; and
restart the drive of the shift register based on the restart of the supply of the shift register clock.
7. The signal processing apparatus according to claim 6 , wherein the processor is further configured to:
count a specific reference clock; and
stop and restart the supply of the shift register clock based on a count value of the count of the specific reference clock.
8. The signal processing apparatus according to claim 6 , wherein the processor is further configured to stop and restart the supply of the shift register clock based on an enable signal.
9. The signal processing apparatus according to claim 5 , wherein the processor is further configured to:
stop the drive of the shift register by initialization of the shift register; and
restart the drive of the shift register by supply of a trigger signal to the shift register.
10. The signal processing apparatus according to claim 9 , wherein the processor is further configured to supply the trigger signal to an operation restarting position of the shift register in a case of the restart of the drive of the shift register.
11. The signal processing apparatus according to claim 5 , further comprising the shift register.
12. The signal processing apparatus according to claim 11 , further comprising:
the holding unit; and
the sense amplifier.
13. A signal processing method, comprising:
performing, by an A/D conversion unit, in a specific period, A/D conversion on a pixel output of an analog signal to obtain digital data; and
stopping, by a processor, driving of a shift register controlling transfer of the digital data,
wherein the drive of the shift register is stopped in one of a part or an entirety of the specific period in which the A/D conversion is performed on the pixel output of the analog signal.
14. An imaging element, comprising:
a pixel array that includes a plurality of pixels,
wherein each pixel of the plurality of pixels is configured to photoelectrically convert incident light;
an A/D conversion unit configured to perform, in a first period, A/D conversion on a first pixel output of an analog signal obtained from the pixel array,
wherein the A/D conversion on the first pixel output is performed to obtain digital data;
a holding unit configured to hold the digital data obtained based on the A/D conversion on the first pixel output by the A/D conversion unit;
a sense amplifier configured to convert the digital data read out from the holding unit from a current to a voltage;
a shift register configured to:
control drive of each of the holding unit and the sense amplifier; and
control transfer of the digital data based on the control of the drive of the holding unit and the sense amplifier; and
a processor configured to stop drive of the shift register in one of a part or an entirety of the first period in which the A/D conversion is performed on the first pixel output by the A/D conversion unit.
15. The imaging element according to claim 14 , wherein the processor is further configured to stop the drive of the shift register from a start timing of the first period in which the A/D conversion is performed on the first pixel output by the A/D conversion unit.
16. The imaging element according to claim 15 , wherein
the processor is further configured to stop the drive of the shift register in one of a part or an entirety of a second period and one of a part or an entirety of a third period,
in the second period, the A/D conversion unit is further configured to perform the A/D conversion on a second pixel output,
the second pixel output is in a reset period of correlated double sampling,
in the third period, the A/D conversion unit is further configured to perform the A/D conversion on a third pixel output, and
the third pixel output is in a signal readout period of the correlated double sampling.
17. The imaging element according to claim 14 , wherein the processor is further configured to:
count a specific reference clock;
stop, based on a count value of the count of the specific reference clock, supply of a shift register clock that drives the shift register;
stop the drive of the shift register based on the stop of the supply of the shift register clock;
restart, based on the count value, the supply of the shift register clock; and
restart the drive of the shift register based on the restart of the supply of the shift register clock.
18. The imaging element according to claim 14 , wherein the processor is further configured to:
stop, based on an enable signal, supply of a shift register clock that drives the shift register;
stop the drive of the shift register based on the stop of the supply of the shift register clock;
restart the supply of the shift register clock based on the enable signal; and
restart the drive of the shift register based on the restart of the supply of the shift register clock.
19. The imaging element according to claim 14 , wherein the processor is further configured to:
stop the drive of the shift register by initialization of the shift register; and
restart the drive of the shift register by supply of a trigger signal to the shift register.
20. An electronic apparatus, comprising:
an imaging unit configured to capture an image of a subject to obtain image data; and
an image processing unit configured to perform image processing on the image data,
wherein the imaging unit includes:
a pixel array that includes a plurality of pixels,
wherein each pixel of the plurality of pixels is configured to photoelectrically convert incident light;
an A/D conversion unit configured to perform, in a specific period, A/D conversion on a pixel output of an analog signal obtained from the pixel array,
wherein the A/D conversion on the pixel output is performed to obtain digital data;
a holding unit configured to hold the digital data obtained based on the A/D conversion on the pixel output by the A/D conversion unit;
a sense amplifier configured to convert the digital data read out from the holding unit from a current to a voltage;
a shift register configured to:
control drive of each of the holding unit and the sense amplifier; and
control transfer of the digital data based on the control of the drive of the holding unit and the sense amplifier; and
a processor configured to stop drive of the shift register in one of a part or an entirety of the specific period in which the A/D conversion is performed on the pixel output by the A/D conversion unit.