Imaging device, control method thereof, and imaging apparatus
In order to provide an imaging device that includes an amplifier performing amplification with a plurality of gains for each signal from a pixel unit and can further reduce a noise component, an imaging device included in an imaging apparatus has the pixel unit in which unit pixels are arranged in a matrix and generates a signal voltage by photoelectric conversion. A column amplifier can amplify a photoelectrically converted signal with a plurality of gains. After an amplified signal is subjected to analog/digital conversion by a column ADC, a signal processing circuit subtracts a noise signal from a pixel signal. A noise signal read out after resetting a floating diffusion section included in the pixel unit and a pixel signal read out immediately thereafter are acquired by being multiplied by a first gain, and a pixel signal read out thereafter is acquired by being multiplied by a second gain. The first gain is set to a value larger than the second gain.
1. An imaging device, comprising:
an amplifier that performs amplification with a plurality of gains for each signal from a photoelectric converter of a pixel unit;
a controller that controls a gain of the amplifier; and
a signal processing circuit that subtracts a noise signal from a pixel signal amplified by the amplifier,
wherein the controller performs control to read out a noise signal with a second gain by the amplifier after resetting the pixel unit and then to read out a noise signal with a first gain by the amplifier, and performs control to read out a pixel signal with the first gain and then to read out a pixel signal with the second gain, and
the first gain is larger than the second gain.
2. The imaging device according to claim 1 , further comprising:
a memory that holds a noise signal read with the second gain until a pixel signal is read out with the second gain.
3. An imaging apparatus comprising:
the imaging device according to claim 1 .
4. The imaging apparatus according to claim 3 , further comprising:
a synthesizing unit that acquires a plurality of signals amplified with different gains by the amplifier and synthesizes images.
5. An imaging device comprising:
an amplifier that performs amplification with a plurality of gains for each signal from a photoelectric converter of a pixel unit;
a controller that controls a gain of the amplifier; and
a signal processing circuit that subtracts a noise signal from a pixel signal amplified by the amplifier,
wherein the controller performs control to read out a noise signal and a pixel signal with a first gain by the amplifier and then to read out a pixel signal with a second gain by the amplifier, after resetting the pixel unit, and performs control to reset the pixel unit again and then to read out a noise signal with the second gain, after reading out a pixel signal with the second gain.
6. The imaging device according to claim 5 ,
wherein the first gain is larger than the second gain.
7. The imaging device according to claim 5 ,
wherein the first gain is smaller than the second gain.
8. The imaging device according to claim 5 , further comprising:
a switch between the pixel unit and the amplifier,
wherein the switch is turned off when resetting the pixel unit again.
9. A control method of an imaging device, which is executed in the imaging device in which a pixel unit has a photoelectric converter, the method comprising:
controlling a gain of an amplifier that performs amplification with a plurality of gains for each signal from the photoelectric converter of the pixel unit;
performing control to read out a noise signal with a second gain by the amplifier after resetting the pixel unit and then to read out a noise signal with a first gain by the amplifier, and to read out a pixel signal with the first gain and then to read out a pixel signal with the second gain; and
subtracting a noise signal from a read out pixel signal amplified by the amplifier, wherein the first gain is larger than the second gain.
10. A control method of an imaging device, which is executed in the imaging device in which a pixel unit has a photoelectric converter, the method comprising:
controlling a gain of an amplifier that performs amplification for each signal from the photoelectric converter;
performing control to read out a noise signal and a pixel signal with a first gain by the amplifier and then to read out a pixel signal with a second gain by the amplifier, after resetting the pixel unit;
performing control to reset the pixel unit again and then to read out a noise signal with the second gain, after reading out a pixel signal with the second gain; and
subtracting a noise signal from a read out pixel signal.