APPARATUS FOR PROCESSING DEAD PIXEL

• US 20070291142A1
• Filed: 06/19/2006
• Published: 12/20/2007
• Est. Priority Date: 06/19/2006
• Status: Active Grant

• Current Assignee: MILA
• Original Assignee: Mtekvision Co.Ltd.
• Inventors: Noh, Yo Hwan, Kim, Wang-Hyun
• Granted Patent: US 7,676,084 B2
• Time in Patent Office: Days
• US Class Current: 348/246
• CPC Class Codes: H04N 23/84 for processing colour signals
• CPC Class Codes: H04N 25/134 based on three different wavelength filter elements
• CPC Class Codes: H04N 25/68 applied to defects

Abstract

The present invention is related to a method and an apparatus for processing a dead pixel, more specifically to a method and an apparatus thereof for detecting and compensating a dead pixel that can maintain a good image quality by reducing image distortion and deterioration. With the present invention, the distortion of an image, caused by erroneously classifying a normal pixel of an inputted image as a dead pixel, is significantly reduced, thereby improving the quality of a processed image. Moreover, based on the characteristics of the inputted image, the algorithm and accuracy of detecting a dead pixel can be adjusted.

Claims

1. An apparatus for detecting a dead pixel, comprising:

a pixel value storage unit, the pixel value storage unit storing a series of pixel values, the pixel values including a reference pixel value;

a dead pixel processing unit, the dead pixel processing unit bypassing said reference pixel value by comparing said reference pixel value with a neighboring same kind pixel value or generating a compensated pixel value by using said neighboring same kind pixel value;

a frequency detection unit, the frequency detection unit generating a frequency bypass flag if the differences between a plurality of same kind pixel values are smaller than a first threshold;

a pattern detection unit, the pattern detection unit generating a pattern bypass flag if the difference between said reference pixel value and a neighboring pixel value is smaller than a second threshold; and

a selection unit, the selection unit selecting one of said reference pixel value and the output value of said dead pixel processing unit by the combination of said frequency bypass flag and said pattern bypass flag.

2. The apparatus for detecting a dead pixel of claim 1, wherein said dead pixel processing unit comprises:

a dead pixel detection unit, the dead pixel detection unit generating a dead pixel bypass flag if said reference pixel value is compared with said neighboring same kind pixel value and determined to be a normal pixel;

a dead pixel compensation unit, the dead pixel compensation unit generating said compensated pixel value using said neighboring same kind pixel value; and

a multiplexer, the multiplexer receiving said reference pixel value and said compensated pixel value, the multiplexer outputting said reference pixel value in accordance with said dead pixel bypass flag.

3. The apparatus for detecting a dead pixel of claim 1, wherein said first threshold or said second threshold is adjustable.

4. The apparatus for detecting a dead pixel of claim 1, wherein the operation of said frequency detection unit and said pattern detection unit is determined by a predetermined register value.

5. The apparatus for detecting a dead pixel of claim 4, wherein said selection unit outputs one of said reference pixel value and an output value of said dead pixel processing unit by the combination of bypass flags corresponding to the operation status of said frequency detection unit and said pattern detection unit.

6. An apparatus for detecting a dead pixel, comprising:

a pixel value storage unit, the pixel value storage unit storing a series of pixel values, the pixel values including a reference pixel value;

a dead pixel processing unit, the dead pixel processing unit bypassing said reference pixel value by comparing said reference pixel value with a neighboring same kind pixel value or generating a compensated pixel value by using said neighboring same kind pixel value;

a pattern detection unit, the pattern detection unit generating a pattern bypass flag if the difference between said reference pixel value and a neighboring pixel value is smaller than a threshold; and

a selection unit, the selection unit selecting one of said reference pixel value and the output value of said dead pixel processing unit by said pattern bypass flag.

7. The apparatus for detecting a dead pixel of claim 6, wherein said threshold is adjustable.

8. The apparatus for detecting a dead pixel of claim 6, wherein the operation of said pattern detection unit is determined by a predetermined register value.

9. An apparatus for detecting a dead pixel, comprising:

a pixel value storage unit, the pixel value storage unit storing a series of pixel values, the pixel values including a reference pixel value;

a dead pixel processing unit, the dead pixel processing unit bypassing said reference pixel value by comparing said reference pixel value with a neighboring same kind pixel value or generating a compensated pixel value by using said neighboring same kind pixel value;

a frequency detection unit, the frequency detection unit generating a frequency bypass flag if the differences between a plurality of same kind pixel values are smaller than a threshold; and

a selection unit, the selection unit selecting one of said reference pixel value and the output value of said dead pixel processing unit by said frequency bypass flag.

10. The apparatus for detecting a dead pixel of claim 9, wherein said threshold is adjustable.

11. The apparatus for detecting a dead pixel of claim 9, wherein the operation of said frequency detection unit is determined by a predetermined register value.