Imaging apparatus and method for driving the same

Patent metadata

Field	Value
Publication number	US-10720464-B2
Application number	US-201815943489-A
Country	US
Kind code	B2
Filing date	Apr 2, 2018
Priority date	Apr 10, 2017
Publication date	Jul 21, 2020
Grant date	Jul 21, 2020

Abstract

An imaging apparatus includes a pixel region having a plurality of unit pixels arranged in a matrix, each of the unit pixels including first and second photoelectric conversion units, a reading controller configured to read first signals obtained by mixing signals output from the first and second photoelectric conversion units in rows of a first reading mode and read second signals at least including signals of the first photoelectric conversion units and third signals at least including signals of the second photoelectric conversion units in rows of a second reading mode, and an OB clamp processor configured to correct signals in the unit pixels included in an opening region in the pixel region based on signals output from the unit pixels included in a light shielding region in the pixel region. The OB clamp processor performs one of various correction processes depending on an imaging condition.

First claim

What is claimed is:

1. An imaging apparatus comprising:
a pixel region having a plurality of unit pixels arranged in a matrix, each of the unit pixels including a micro lens and first and second photoelectric conversion units receiving light which is transmitted through the micro lens;
a reading controller configured to read first signals obtained by mixing signals output from the first and second photoelectric conversion units in rows of a first reading mode and read second signals at least including signals of the first photoelectric conversion units and third signals at least including signals of the second photoelectric conversion units in rows of a second reading mode; and
an optical black (OB) clamp processor configured to correct signals in the unit pixels included in an opening region in the pixel region based on signals output from the unit pixels included in a light shielding region in the pixel region,
wherein the OB clamp processor performs one of various correction processes depending on an imaging condition.

2. The imaging apparatus according to claim 1 ,
wherein the second signals are output from the first photoelectric conversion units, and
the third signals are output from the second photoelectric conversion units.

3. The imaging apparatus according to claim 1 ,
wherein the second signals are output from the first photoelectric conversion units, and
the third signals are obtained by mixing the signals output from the first and second photoelectric conversion units.

4. The imaging apparatus according to claim 1 ,
wherein the OB clamp processor
corrects the second signals of the unit pixels in the opening region in the pixel region based on the first signals and the second signals of the unit pixels included in the light shielding region in the pixel region and corrects the third signals of the unit pixels in the opening region in the pixel region based on the first signals and the third signals of the unit pixels included in the light shielding region in the pixel region when the imaging condition is a first condition, and
corrects the second signals of the unit pixels included in the opening region in the pixel region based on the second signals of the unit pixels included in the light shielding region in the pixel region and corrects the third signals of the unit pixels included in the opening region in the pixel region based on the third signals of the unit pixels included in the light shielding region in the pixel region when the imaging condition is a second condition.

5. The imaging apparatus according to claim 1 ,
wherein the OB clamp processor includes
a first OB clamp processor which corrects the second signals of the unit pixels included in the opening region in the pixel region based on the first signals and the second signals of the unit pixels included in the light shielding region in the pixel region and corrects the third signals of the unit pixels included in the opening region in the pixel region based on the first signals and the third signals of the unit pixels included in the light shielding region in the pixel region, and
a second OB clamp processor which corrects the second signals of the unit pixels included in the opening region in the pixel region based on the second signals of the unit pixels included in the light shielding region in the pixel region and corrects the third signals of the unit pixels included in the opening region in the pixel region based on the third signals of the unit pixels included in the light shielding region in the pixel region,

the first OB clamp processor performs correction when the imaging condition is a first condition, and
the first OB clamp processor performs correction and the second OB clamp processor performs correction on signals which have been corrected by the first OB clamp processing when the imaging condition is the second condition.

6. The imaging apparatus according to claim 1 ,
wherein the reading controller
performs reading in the first reading mode on a number of rows of the plurality of unit pixels and performs reading in the second reading mode on the other rows of the plurality of unit pixels when the imaging condition is a first condition, and
performs reading in the first reading mode on all the rows of the plurality of unit pixels when the imaging condition is a second condition.

7. The imaging apparatus according to claim 6 ,
wherein the OB clamp processor includes a first OB clamp processor which corrects the second signals of the unit pixels included in the opening region in the pixel region based on differences between the first signals and the second signals of the unit pixels included in the light shielding region in the pixel region and corrects the third signals of the unit pixels included in the opening region in the pixel region based on differences between the first signals and the third signals of the unit pixels included in the light shielding region in the pixel region, and
the first OB clamp processor operates when the imaging condition is the first condition.

8. The imaging apparatus according to claim 7 ,
wherein the OB clamp processor includes a second OB clamp processor which corrects signals of the unit pixels included in the opening region in the pixel region based on error amounts between signals of the unit pixels included in the light shielding region in the pixel region and a dark level target value, and
the second OB clamp processor operates when the imaging condition is the first condition and the second condition.

9. The imaging apparatus according to claim 1 , wherein the imaging condition includes an ISO speed.

10. The imaging apparatus according to claim 1 , wherein the imaging condition includes a shutter speed.

11. A method for driving an imaging apparatus having a pixel region including a plurality of unit pixels arranged in a matrix, each of the unit pixels including a micro lens and first and second photoelectric conversion units receiving light which is transmitted through the micro lens, the method comprising:
reading first signals obtained by mixing signals of the first and second photoelectric conversion units in rows of a first reading mode and reading second signals at least including signals of the first photoelectric conversion units and third signals at least including signals of the second photoelectric conversion units in rows of a second reading mode; and
correcting signals in the unit pixels included in an opening region in the pixel region based on signals output from the unit pixels included in a light shielding region in the pixel region,
wherein one of various correction processes is performed depending on an imaging condition in the correcting.

12. The method according to claim 11 ,
wherein the second signals are output from the first photoelectric conversion units, and
the third signals are output from the second photoelectric conversion units.

13. The method according to claim 11 ,
wherein the second signals are output from the first photoelectric conversion units, and
the third signals are obtained by mixing the signals output from the first and second photoelectric conversion units.

14. The method according to claim 11 , further comprising:
correcting the second signals of the unit pixels included in the opening region in the pixel region based on the first signals and the second signals of the unit pixels included in the light shielding region in the pixel region and corrects the third signals of the unit pixels in the opening region in the pixel region based on the first signals and the third signals of the unit pixels included in the light sh

Assignees

• Canon Kk

Inventors

• Sambonsugi Hideaki
• Uchida Mineo

Classifications

• H04N25/40

  Extracting pixel data from image sensors by controlling scanning circuits, e.g. by modifying the number of pixels sampled or to be sampled · CPC title

• H04N25/704

  Pixels specially adapted for focusing, e.g. phase difference pixel sets · CPC title

• H04N23/80

  Camera processing pipelines; Components thereof · CPC title

• H04N23/67

  Focus control based on electronic image sensor signals · CPC title

• H04N23/72

  Combination of two or more compensation controls · CPC title