Image capturing system, signal processing circuit, and signal processing method

• US 8,072,513 B2
• Filed: 04/17/2008
• Issued: 12/06/2011
• Est. Priority Date: 05/02/2007
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Takenaka, Shintaro, Sonoda, Kazuhiro, Kitani, Kazunari
• Primary Examiner(s): Tran, Nhan T
• Assistant Examiner(s): HOGUE, DENNIS A
• Application Number:
  US12/104,991
• Publication Number:
  US 20080273101A1
• Time in Patent Office: 1,328 Days
• Field of Search: None
• US Class Current: 348/246
• 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 optical black pixels arranged in rows and columns for outputting a dark reference signal, on the basis of a signal output from a normal pixel in the optical black region,

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

wherein each of the plurality of pixel blocks has at least three pixels arranged in a column and each having a photoelectric conversion element,

wherein optical black pixels of each pixel block share an amplifying element provided to the pixel block,

wherein relative positions of the photoelectric conversion elements of the optical black pixels of the pixel block, which are positions relative to the shared amplifying element provided to the pixel block, are different from each other,

wherein the signal correction unit corrects the signal output from the defective pixel 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 and in the same column and a different row from the defective pixel, and

wherein a relative position of the photoelectric conversion element of the normal pixel, which is a position relative to the shared amplifying element provided to the another pixel block, is the same as a relative position of the photoelectric conversion element of the defective pixel, which is a position relative to the shared amplifying element provided to the pixel block of the defective pixel.

2. The system according to claim 1, wherein the signal correction unit corrects the signal output from the defective pixel on the basis of signals output from a plurality of normal pixels which are included in other pixel blocks different from the pixel block of the defective pixel, and

wherein relative positions of the photoelectric conversion elements of the plurality of normal pixels, which are positions relative to the corresponding shared amplifying elements provided to the other pixel blocks, are the same as the relative position of the photoelectric conversion element of the defective pixel.

3. The system according to claim 1, wherein each optical black pixel in each pixel block further includes a transistor.

4. The system according to claim 3, wherein each pixel block includes a reset transistor which sets a potential of an input portion of a transistor to a reference value.

5. The system according to claim 1, wherein the signal correction unit corrects the signal output from the defective pixel on the basis of an average value of signals output from a plurality of normal pixels which are included in other pixel blocks different from the pixel block of the defective pixel, and

wherein relative positions of the photoelectric conversion elements of the plurality of normal pixels, which are positions relative to the corresponding shared amplifying elements provided to said other pixel blocks, are same as the relative position of the photoelectric conversion element of the defective pixel.

6. The system according to claim 1, 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.