Image capturing apparatus with correction using optical black areas, control method therefor and program

• US 8,339,482 B2
• Filed: 01/22/2010
• Issued: 12/25/2012
• Est. Priority Date: 02/03/2009
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Okado, Teruyuki
• Primary Examiner(s): Villecco, John
• Assistant Examiner(s): GEBRIEL, SELAM T
• Application Number:
  US12/692,121
• Publication Number:
  US 20100194935A1
• Time in Patent Office: 1,068 Days
• Field of Search: 348241-251, 348/345
• US Class Current: 348/248
• CPC Class Codes: H04N 25/625 for the control of smear
• CPC Class Codes: H04N 25/63 applied to dark current
• CPC Class Codes: H04N 25/633 by using optical black pixels
• CPC Class Codes: H04N 25/677 for reducing the column or line fixed pattern noise
• CPC Class Codes: H04N 25/76 Addressed sensors, e.g. MOS or CMOS sensors

Abstract

An image capturing apparatus comprises: an image sensor having an effective pixel area where plural pixels not shield from light are two-dimensionally arranged, and a first optical black area and a second optical black area including pixels shielded from light provided on the both sides of the effective pixel area; and a correction unit to, upon incident of high luminance light on the image sensor, correct an output signal of a pixel between a high luminance portion as a pixel part on which the high luminance light is incident in the effective pixel area and the first optical black area using an output signal of the first optical black area, and correct an output signal of a pixel between the high luminance portion and the second optical black area, using an output signal of the second optical black area.

Claims

1. An image capturing apparatus comprising:

an image sensor having an effective pixel area where plural pixels not shielded from light are two-dimensionally arranged, and a first optical black area and a second optical black area including pixels shielded from light, provided on the both sides of the effective pixel area;

a correction unit configured to, upon incident of high luminance light on said image sensor, determine a position of a high luminance portion as a pixel part on which said high luminance light is incident in said effective pixel area and correct an output signal of a pixel between said high luminance portion and said first optical black area using an output signal of said first optical black area, and correct an output signal of a pixel between said high luminance portion and said second optical black area, using an output signal of said second optical black area, in accordance with the position of said high luminance portion.

2. The image capturing apparatus according to claim 1, wherein said correction unit uses a value obtained by multiplying the output signal of said first optical black area or the output signal of said second optical black area by a predetermined coefficient in correspondence with a distance between a position of said high luminance portion and a correction subject pixel as a subject of correction, as a correction amount.

3. The image capturing apparatus according to claim 1, wherein the output signal of the pixel between said high luminance portion and said first optical black area and the output signal of the pixel between said high luminance portion and said second optical black area upon incident of the high luminance light on said effective pixel area are previously stored, and wherein said correction unit calculates a correction amount based on the stored information.

4. The image capturing apparatus according to claim 3, wherein said correction unit uses a value obtained by multiplying said stored information by a predetermined coefficient as the correction amount.

5. A method for controlling an image capturing apparatus which has an image sensor having an effective pixel area where plural pixels not shielded from light are two-dimensionally arranged, and a first optical black area and a second optical black area including pixels shielded from light, provided on the both sides of the effective pixel area, comprising:

a correction step of, upon incident of high luminance light on said image sensor, determining a position of a high luminance portion as a pixel part on which said high luminance light is incident in said effective pixel area and correcting an output signal of a pixel between said high luminance portion and said first optical black area using an output signal of said first optical black area, and correcting an output signal of a pixel between said high luminance portion and said second optical black area, using an output signal of said second optical black area, in accordance with the position of said high luminance portion.