Signal processing apparatus, signal processing method, image pickup element, and imaging apparatus
View Patent ↗Provided is a signal processing apparatus, including: an A/D conversion unit configured to perform A/D conversion of a first signal, A/D conversion of a second signal, A/D conversion of a third signal, and A/D conversion of a fourth signal; and a correlated double sampling processing unit configured to generate a first output signal by performing correlated double sampling using a first digital data item obtained through the A/D conversion of the first signal, and a second digital data item obtained through the A/D conversion of the second signal, a second output signal by performing correlated double sampling using a third digital data item obtained through the A/D conversion of the third signal, and a fourth digital data item obtained through the A/D conversion of the fourth signal, and a third output signal by performing correlated double sampling using the first output signal and the second output signal.
1. A signal processing apparatus, comprising:
an A/D conversion unit configured to perform
A/D conversion of a first signal that is read out from unit pixels under a state in which reset signals of the unit pixels have been set to be high by a shutter operation of resetting floating diffusions of the unit pixels, the unit pixels being configured to perform photoelectric conversion of incident light under a state in which full depletion is prevented,
A/D conversion of a second signal that is read out from the unit pixels under a state in which the reset signals of the unit pixels have been set to be low by the shutter operation,
A/D conversion of a third signal that is read out from the unit pixels under a state in which the reset signals of the unit pixels have been set to be low by a read operation of reading out electric charge from the floating diffusions of the unit pixels, the electric charge being obtained through the photoelectric conversion, and
A/D conversion of a fourth signal that is read out from the unit pixels under a state in which the reset signals of the unit pixels have been set to be high by the read operation; and
a correlated double sampling processing unit configured to generate
a first output signal by performing correlated double sampling using
a first digital data item obtained through the A/D conversion of the first signal by the A/D conversion unit, and
a second digital data item obtained through the A/D conversion of the second signal by the A/D conversion unit,
a second output signal by performing correlated double sampling using
a third digital data item obtained through the A/D conversion of the third signal by the A/D conversion unit, and
a fourth digital data item obtained through the A/D conversion of the fourth signal by the A/D conversion unit, and
a third output signal by performing correlated double sampling using
the first output signal, and
the second output signal.
2. The signal processing apparatus according to claim 1 , further comprising a storage unit configured to store the first digital data item, the second digital data item, the third digital data item, and the fourth digital data item that are obtained by the A/D conversion unit,
wherein the correlated double sampling processing unit is configured to perform correlated double sampling by using one of a pair of the first digital data item and the second digital data item that are read out from the storage unit and a pair of the third digital data item and the fourth digital data item that are read out from the storage unit.
3. The signal processing apparatus according to claim 2 , wherein
the storage unit is configured to further store the first output signal that is generated by the correlated double sampling processing unit, and
the correlated double sampling processing unit is configured to perform correlated double sampling by using the second output signal that is generated by the correlated double sampling processing unit and the first output signal that is read out from the storage unit.
4. The signal processing apparatus according to claim 1 , further comprising a clamp control unit configured to clamp a reference signal having a ramp waveform such that, in the A/D conversion unit,
the A/D conversion of the first signal that is read out from the unit pixels under the state in which the reset signals of the unit pixels have been set to be high by the shutter operation is properly performed through comparison between the first signal and the reference signal having the ramp waveform, and that
the A/D conversion of the fourth signal that is read out from the unit pixels under the state in which the reset signals of the unit pixels have been set to be high by the read operation is properly performed through comparison between the fourth signal and the reference signal having the ramp waveform.
5. An image pickup element, comprising:
unit pixels configured to perform photoelectric conversion of incident light under a state in which full depletion is prevented;
an A/D conversion unit configured to perform
A/D conversion of a first signal that is read out from the unit pixels under a state in which reset signals of the unit pixels have been set to be high by a shutter operation of resetting floating diffusions of the unit pixels,
A/D conversion of a second signal that is read out from the unit pixels under a state in which the reset signals of the unit pixels have been set to be low by the shutter operation,
A/D conversion of a third signal that is read out from the unit pixels under a state in which the reset signals of the unit pixels have been set to be low by a read operation of reading out electric charge from the floating diffusions of the unit pixels, the electric charge being obtained through the photoelectric conversion, and
A/D conversion of a fourth signal that is read out from the unit pixels under a state in which the reset signals of the unit pixels have been set to be high by the read operation; and
a correlated double sampling processing unit configured to generate
a first output signal by performing correlated double sampling using
a first digital data item obtained through the A/D conversion of the first signal by the A/D conversion unit, and
a second digital data item obtained through the A/D conversion of the second signal by the A/D conversion unit,
a second output signal by performing correlated double sampling using
a third digital data item obtained through the A/D conversion of the third signal by the A/D conversion unit, and
a fourth digital data item obtained through the A/D conversion of the fourth signal by the A/D conversion unit, and
a third output signal by performing correlated double sampling using
the first output signal, and
the second output signal.
6. The image pickup element according to claim 5 , wherein
the unit pixels each include a photoelectric conversion unit that performs the photoelectric conversion of the incident light and is connected to corresponding one of the floating diffusions by wire bonding.
7. The image pickup element according to claim 5 , wherein
the unit pixels each include a pixel structure that performs color separation in a vertical direction with respect to a substrate.
8. The image pickup element according to claim 7 , wherein
the unit pixels each perform
color separation into green by using an organic photoelectric conversion film, and
color separation into red and blue respectively in accordance with silicon depths.
9. The image pickup element according to claim 7 , wherein
the unit pixels each perform color separation into green, red, and blue respectively in accordance with silicon depths.
10. An imaging apparatus, comprising:
an imaging unit configured to image a photographic subject; and
an image processing unit configured to execute image processes on captured image data obtained by the imaging unit, the imaging unit including
unit pixels configured to perform photoelectric conversion of incident light under a state in which full depletion is prevented,
an A/D conversion unit configured to perform
A/D conversion of a first signal that is read out from the unit pixels under a state in which reset signals of the unit pixels have been set to be high by a shutter operation of resetting floating diffusions of the unit pixels,
A/D conversion of a second signal that is read out from the unit pixels under a state in which the reset signals of the unit pixels have been set to be low by the shutter operation,
A/D conversion of a third signal that is read out from the unit pixels under a state in which the reset signals of the unit pixels have been set to be low by a read operation of reading out electric charge from the floating diffusions of the unit pixels, the electric charge being obtained through the photoelectric conversion, and
A/D conversion of a fourth signal that is read out from the unit pixels under a state in which the reset signals of the unit pixels have been set to be high by the read operation, and
a correlated double sampling processing unit configured to generate
a first output signal by performing correlated double sampling using
a first digital data item obtained through the A/D conversion of the first signal by the A/D conversion unit, and
a second digital data item obtained through the A/D conversion of the second signal by the A/D conversion unit,
a second output signal by performing correlated double sampling using
a third digital data item obtained through the A/D conversion of the third signal by the A/D conversion unit, and
a fourth digital data item obtained through the A/D conversion of the fourth signal by the A/D conversion unit, and
a third output signal by performing correlated double sampling using
the first output signal, and
the second output signal.