IMAGE CAPTURING SYSTEM, SIGNAL PROCESSING CIRCUIT, AND SIGNAL PROCESSING METHOD

• US 20080273101A1
• Filed: 04/17/2008
• Published: 11/06/2008
• Est. Priority Date: 05/02/2007
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Sonoda, Kazuhiro, Takenaka, Shintaro, Kitani, Kazunari
• Granted Patent: US 8,072,513 B2
• Time in Patent Office: Days
• US Class Current: 348/243
• CPC Class Codes: H04N 25/63 applied to dark current
• CPC Class Codes: H04N 25/67 applied to fixed-pattern noise, e.g. non-uniformity of response
• CPC Class Codes: H04N 25/68 applied to defects

Abstract

An image capturing system includes a signal correction unit which corrects a signal output from a defective pixel in an optical black region based on a signal output from a normal pixel. The optical black region has a plurality of pixel blocks. Each of the plurality of pixel blocks has a plurality of pixels each including one or more elements which have the same functions as in the remaining pixels and which have relative positions different from the remaining pixels. The signal correction unit corrects the signal output from the defective pixel in the optical black region based on a signal output from a normal pixel which is included in another pixel block different from the pixel block of the defective pixel in the optical black region and includes one or more elements having the same functions and same relative positions as in the defective pixel.

Claims

1. An image capturing system comprising:

a signal correction unit which corrects a signal output from a defective pixel in an optical black region having a plurality of pixels for outputting a dark reference signal, on the basis of a signal output from a normal pixel;

wherein the optical black region has a plurality of pixel blocks,

each of the plurality of pixel blocks has a plurality of pixels each including at least one element which has the same function as in the remaining pixels and which has a relative position different from the remaining pixels, and

the signal correction unit corrects the signal output from the defective pixel in the optical black region on the basis of a signal output from a normal pixel which is included in another pixel block different from the pixel block of the defective pixel in the optical black region and includes at least one element having the same function and same relative position as in the defective pixel.

2. The system according to claim 1, wherein

the signal correction unit corrects the signal output from the defective pixel in the optical black region on the basis of signals output from a plurality of normal pixels which are included in another pixel block different from the pixel block of the defective pixel in the optical black region and include at least one element having the same function and same relative position as in the defective pixel.

3. The system according to claim 1, wherein the at least one element includes a photoelectric conversion element.

4. The system according to claim 3, wherein

the at least one element includes a transistor in addition to the photoelectric conversion element.

5. The system according to claim 4, wherein the transistor includes:

an amplification transistor which amplifies a signal output from each of the plurality of pixels of the pixel block; and

a reset transistor which sets a potential of an input portion of the amplification transistor to a reference value.

6. The system according to claim 2, wherein

the signal correction unit corrects the signal output from the defective pixel in the optical black region on the basis of an average value of signals output from a plurality of normal pixels which are included in another pixel block different from the pixel block of the defective pixel in the optical black region and include at least one element having the same function and same relative position as in the defective pixel.

8. The system according to claim 1, the system further comprising:

an image sensing apparatus having the optical black region and an effective area adjacent to the optical black region; and

a memory which records a signal output from each pixel in the optical black region, and address information of each pixel,

wherein the signal correction unit corrects the signal output from the defective pixel on the basis of the signal output from the normal pixel by referring to the memory.

7. An image capturing system comprising:

a signal correction unit which corrects a signal output from a defective pixel in an optical black region having a plurality of pixels for outputting a dark reference signal, on the basis of a signal output from a normal pixel;

wherein the optical black region has a plurality of pixel blocks,

each of the plurality of pixel blocks has a plurality of pixels each including a plurality of transistors which have the same functions as in the remaining pixels and which have relative positions different from the remaining pixels, and

the signal correction unit corrects the signal output from the defective pixel in the optical black region on the basis of a signal output from a normal pixel which is included in another pixel block different from the pixel block of the defective pixel in the optical black region and includes a plurality of transistors having the same functions and same relative positions as in the defective pixel.

9. An image capturing system comprising:

a signal correction unit which corrects a signal output from a defective pixel in an optical black region having a plurality of pixels for outputting a dark reference signal, on the basis of a signal output from a normal pixel;

wherein the optical black region has a plurality of pixel blocks,

each of the plurality of pixel blocks includes a plurality of pixels having different pixel structures, and

the signal correction unit corrects the signal output from the defective pixel in the optical black region on the basis of a signal output from a normal pixel which is included in another pixel block different from the pixel block of the defective pixel in the optical black region and has the same pixel structure as in the defective pixel.

10. A signal processing circuit having a signal correction unit which corrects a signal output from a defective pixel in an optical black region having a plurality of pixels for outputting a dark reference signal, on the basis of a signal output from a normal pixel, wherein

the optical black region has a plurality of pixel blocks,

each of the plurality of pixel blocks has a plurality of pixels each including at least one element which has the same function as in the remaining pixels and which has a relative position different from the remaining pixels, and

the signal correction unit corrects the signal output from the defective pixel in the optical black region on the basis of a signal output from a normal pixel which is included in another pixel block different from the pixel block of the defective pixel in the optical black region and includes at least one element having the same function and same relative position as in the defective pixel.

11. A signal processing circuit having a signal correction unit which corrects a signal output from a defective pixel in an optical black region having a plurality of pixels for outputting a dark reference signal, on the basis of a signal output from a normal pixel, wherein

the optical black region has a plurality of pixel blocks,

each of the plurality of pixel blocks includes a plurality of pixels having different pixel structures, and

the signal correction unit corrects the signal output from the defective pixel in the optical black region on the basis of a signal output from a normal pixel which is included in another pixel block different from the pixel block of the defective pixel in the optical black region and has the same pixel structure as in the defective pixel.

12. A signal processing method of an image sensing apparatus for correcting a signal output from a defective pixel in an optical black region having a plurality of pixel blocks each including a plurality of pixels for outputting a dark reference signal, each of the plurality of pixels including at least one element which has the same function as in the remaining pixels and which has a relative position different from the remaining pixels, the method comprising:

a first step of determining whether a signal output from a target pixel is an abnormal output or an normal output;

a second step of, when it is determined in the first step that the signal output from the target pixel is a normal output, recording the signal output from the target pixel, and an address of the target pixel as an address of a normal pixel;

a third step of, when it is determined in the first step that the signal output from the target pixel is an abnormal output, determining the address of the target pixel as an address of a defective pixel; and

a fourth step of correcting, based on the address of the normal pixel obtained in the second step and the address of the defective pixel obtained in the third step, the signal output from the defective pixel in the optical black region on the basis of a signal output from a normal pixel which is included in another pixel block different from the pixel block of the defective pixel in the optical black region and includes at least one element having the same function and same relative position as in the defective pixel.

13. A signal processing method of an image sensing apparatus for correcting a signal output from a defective pixel in an optical black region having a plurality of pixel blocks each including a plurality of pixels for outputting a dark reference signal, the plurality of pixels having different pixel structures, the method comprising:

a first step of determining whether a signal output from a target pixel is an abnormal output or an normal output;

a second step of, when it is determined in the first step that the signal output from the target pixel is a normal output, recording the signal output from the target pixel, and an address of the target pixel as an address of a normal pixel;

a third step of, when it is determined in the first step that the signal output from the target pixel is an abnormal output, determining the address of the target pixel as an address of a defective pixel; and

a fourth step of correcting, based on the address of the normal pixel obtained in the second step and the address of the defective pixel obtained in the third step, the signal output from the defective pixel in the optical black region on the basis of a signal output from a normal pixel which is included in another pixel block different from the pixel block of the defective pixel in the optical black region and has the same pixel structure as in the defective pixel.

14. An image capturing system comprising:

a signal correction unit which corrects a signal output from an effective pixel including a photoelectric conversion element in an effective area on the basis of a signal output from a non-effective pixel including no photoelectric conversion element in a non-effective area,

wherein the effective area has a plurality of effective pixel blocks,

each of the plurality of effective pixel blocks has a plurality of effective pixels each including at least one element except the photoelectric conversion element, which has the same function as in the remaining effective pixels and which has a relative position different from the remaining effective pixels,

the non-effective area has a plurality of non-effective pixel blocks,

each of the plurality of non-effective pixel blocks has a plurality of non-effective pixels each including at least one element except the photoelectric conversion element, which has the same function as in the remaining non-effective pixels and which has a relative position different from the remaining non-effective pixels, and

the signal correction unit corrects the signal output from the effective pixel in the effective area on the basis of a signal output from a non-effective pixel which is included in the non-effective area and includes at least one element except the photoelectric conversion element, which has the same function and same relative position as in the effective pixel.

15. The system according to claim 14, further comprising:

a first addition unit which generates a sum signal of effective pixels; and

a second addition unit which generates a sum signal of non-effective pixels,

wherein the signal correction unit corrects a sum signal of effective pixels generated by causing the first addition unit to add a signal output from a first effective pixel and a signal output from a second effective pixel in the effective area, on the basis of a sum signal of non-effective pixels generated by causing the second addition unit upon adding a signal output from a first non-effective pixel which includes at least one element having the same function and same relative position as in the first effective pixel and a signal output from a second non-effective pixel equal to the second effective pixel.