Method for correcting pixel defect in image sensing element, and image sensing apparatus using the same

• US 20050030395A1
• Filed: 08/06/2004
• Published: 02/10/2005
• Est. Priority Date: 08/08/2003
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Hattori, Yuuichirou
• Granted Patent: US 7,375,749 B2
• Time in Patent Office: Days
• US Class Current: 348/246
• CPC Class Codes: G06T 3/403 Edge-driven scaling; Edge-based scaling
• CPC Class Codes: H04N 25/683 by defect estimation performed on the scene signal, e.g. real time or on the fly detection

Abstract

An object of this invention is to provide an image sensing apparatus and image sensing method capable of eliminating a nonvolatile memory for storing position information of a defective pixel, and detecting a defective pixel at high precision even while sensing a complicated object. To achieve this object, there is provided an image sensing apparatus including a solid-state image sensing element having a plurality of pixels which output image sensing signals, a first determination device which determines whether a pixel of interest is a defective pixel candidate, by comparing the signal level of the pixel of interest subjected to defective pixel detection out of the plurality of pixels of the solid-state image sensing element, and the signal levels of a plurality of peripheral pixels around the pixel of interest, and a second determination device which, when the-first determination device determines that the pixel of interest is the defective pixel candidate, determines whether the determination result representing that the pixel of interest is the defective pixel candidate is erroneous detection, on the basis of the determination result of the first determination device representing whether a plurality of peripheral pixels around the pixel of interest are defective pixel candidates.

Claims

1. An image sensing apparatus comprising:

a detection device which detects a defective pixel candidate by determining whether or not each pixel in a plurality of pixels in an image sensing element is a defective pixel candidate; and

a determination device which determines whether or not the defective pixel candidate is a defective pixel by referring a detection result of said detection device.

2. The apparatus according to claim 1, further comprising a correction device which corrects the defective pixel candidate in the case that the defective pixel candidate is determined as the defective pixel by said determination device.

3. The apparatus according to claim 1, wherein said determination device determines whether or not a defective pixel candidate is a defective pixel on the basis of whether or not a defective pixel candidate detected by said detection device exists in a periphery of the defective pixel candidate.

4. The apparatus according to claim 1, further comprising a control device which controls a combination of detection results of the defective pixel candidates referred to by said determination device.

5. The apparatus according to claim 4, wherein said control device controls the combination of detection results of the defective pixel candidates on the basis of an image sensing condition.

6. The apparatus according to claim 5, wherein the image sensing condition includes an ambient temperature of the image sensing element.

7. The apparatus according to claim 5, wherein the image sensing condition includes an exposure time in the image sensing element.

8. The apparatus according to claim 1, further comprising an image sensing lens which forms an image on the image sensing element, and an A/D converter which A/D-converts a signal from the image sensing element and transfers the signal to said detection device.

9. An image sensing method for an image sensing apparatus having a image sensing element with a plurality of pixels which output image sensing signals, comprising:

a detection step of detecting a defective pixel candidate by determining whether or not each pixel in a plurality of pixels in the image sensing element is a defective pixel candidate; and

a determination step of determining whether or not the defective pixel candidate is a defective pixel by referring a detection result in said detection step; and

a correction step of correcting the defective pixel candidate in the case that the defective pixel candidate is determined as the defective pixel in said determination step.