IMAGING APPARATUS HAVING CORRECTION OF SIGNAL DIFFERENCE

• US 20200137328A1
• Filed: 10/15/2019
• Published: 04/30/2020
• Est. Priority Date: 10/24/2018
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Masuyama, Kimihiro
• Granted Patent: US 11,082,648 B2
• Time in Patent Office: Days
• CPC Class Codes: H04N 25/60 Noise processing, e.g. detecting, correcting, reducing or removing noise
• CPC Class Codes: H04N 25/67 applied to fixed-pattern noise, e.g. non-uniformity of response
• CPC Class Codes: H04N 25/671 for non-uniformity detection or correction
• CPC Class Codes: H04N 25/673 by using reference sources
• CPC Class Codes: H04N 25/677 for reducing the column or line fixed pattern noise
• CPC Class Codes: H04N 25/75 Circuitry for providing, modifying or processing image signals from the pixel array
• CPC Class Codes: H04N 25/76 Addressed sensors, e.g. MOS or CMOS sensors
• CPC Class Codes: H04N 25/77 Pixel circuitry, e.g. memories, A/D converters, pixel amplifiers, shared circuits or shared components
• CPC Class Codes: H04N 25/78 Readout circuits for addressed sensors, e.g. output amplifiers or A/D converters

Abstract

An imaging apparatus includes a first pixel, a second pixel, a controller, and a correction circuit. The first pixel has a first photoelectric conversion portion. The second pixel has a second photoelectric conversion portion. The controller controls to output a first signal based on reset release of the first pixel and a second signal based on reset release of the second pixel in a first period, and to output a third signal based on photoelectric conversion of the first pixel and a fourth signal based on reset release of the second pixel in a second period. The correction circuit corrects a difference between the third signal and the first signal, using a difference between the fourth signal and the second signal.

Claims

1. An imaging apparatus comprising:

a first pixel having a first photoelectric conversion portion;

a second pixel having a second photoelectric conversion portion;

a controller that controls to output a first signal based on reset release of the first pixel and a second signal based on reset release of the second pixel in a first period, and to output a third signal based on photoelectric conversion of the first pixel and a fourth signal based on reset release of the second pixel in a second period; and

a correction circuit that corrects a difference between the third signal and the first signal using a difference between the fourth signal and the second signal.

2. The imaging apparatus according to claim 1,

wherein the first pixel includes the first photoelectric conversion portion that converts light into electric charge, a first accumulation portion, and a first transfer switch that transfers the electric charge converted by the first photoelectric conversion portion to the first accumulation portion, and the first pixel outputs a signal corresponding to an electric charge amount of the first accumulation portion, and

wherein the second pixel includes the second photoelectric conversion portion that converts light into electric charge, a second accumulation portion, and a second transfer switch that transfers the electric charge converted by the second photoelectric conversion portion to the second accumulation portion, and the second pixel outputs a signal corresponding to an electric charge amount of the second accumulation portion.

3. The imaging apparatus according to claim 2, wherein the controller performs control to output the first signal based on reset release of the first accumulation portion in a state where the first transfer switch of the first pixel is in an OFF state and output the second signal based on reset release of the second accumulation portion in a state where the second transfer switch of the second pixel is in an OFF state, in the first period, and to output the third signal based on photoelectric conversion of the first photoelectric conversion portion in a state where the first transfer switch of the first pixel is in an ON state and output the fourth signal based on reset release of the second accumulation portion in a state where the second transfer switch of the second pixel is in the OFF state, in the second period.

4. The imaging apparatus according to claim 1, further comprising:

a first output line; and

a second output line,

wherein the first pixel outputs the first signal to the first output line and the second pixel outputs the second signal to the second output line in the first period, and the first pixel outputs the third signal to the first output line and the second pixel outputs the fourth signal to the second output line in the second period.

5. The imaging apparatus according to claim 1, wherein the correction circuit subtracts the difference between the fourth signal and the second signal from the difference between the third signal and the first signal.

6. The imaging apparatus according to claim 1, further comprising:

a row of the first pixels each including the first photoelectric conversion portion; and

a row of the second pixels each including the second photoelectric conversion portion,

wherein the correction circuit performs correction column by column.

7. The imaging apparatus according to claim 6, wherein two rows of the first pixels and two rows of the second pixels are alternately arranged.

8. The imaging apparatus according to claim 1, comprising the first pixel shielded from light, the first pixel not shielded from light, the second pixel shielded from light, and the second pixel not shielded from light.

9. The imaging apparatus according to claim 1,

wherein in a frame in which a noise source operates, the controller performs control to output the first signal based on reset release of the first pixel and the second signal based on reset release of the second pixel in the first period, and to output the third signal based on photoelectric conversion of the first pixel and the fourth signal based on reset release of the second pixel in the second period,

wherein the correction circuit corrects the difference between the third signal and the first signal using the difference between the fourth signal and the second signal, and

wherein in a frame in which the noise source does not operate, the controller performs control to output the first signal based on reset release of the first pixel in the first period, and to output the third signal based on photoelectric conversion of the first pixel in the second period.

10. The imaging apparatus according to claim 4,

wherein in a frame in which a noise source operates, the controller performs control to output the first signal based on reset release of the first pixel to the first output line and the second signal based on reset release of the second pixel to the second output line in the first period, and to output the third signal based on photoelectric conversion of the first pixel to the first output line and the fourth signal based on reset release of the second pixel to the second output line in the second period,

wherein the correction circuit corrects the difference between the third signal and the first signal, using the difference between the fourth signal and the second signal, and

wherein in a frame in which the noise source does not operate, the controller performs control to output the first signal based on reset release of the first pixel to the first output line in the first period, and to output the third signal based on photoelectric conversion of the first pixel to the first output line in the second period.

11. The imaging apparatus according to claim 10, further comprising:

a first current source that is connected to the first output line; and

a second current source that is connected to the second output line,

wherein in the frame in which the current source operates, each of the first current source and the second current source is in an ON state, and

wherein in the frame in which the current source does not operate, the first current source is in the ON state and the second current source is in an OFF state.

12. The imaging apparatus according to claim 9, wherein the frame in which the noise source operates is a frame in which a lens is driven, and the frame in which the noise source does not operate is a frame in which the lens is not driven.