APPARATUS FOR PROCESSING DEAD PIXEL

• US 20080079826A1
• Filed: 10/02/2006
• Published: 04/03/2008
• Est. Priority Date: 10/02/2006
• Status: Active Grant

• Current Assignee: MILA
• Original Assignee: Mtekvision Co.Ltd.
• Inventors: Noh, Yo-Hwan
• Granted Patent: US 7,649,555 B2
• Time in Patent Office: Days
• US Class Current: 348/246
• CPC Class Codes: H04N 25/68 applied to defects
• CPC Class Codes: H04N 25/683 by defect estimation performed on the scene signal, e.g. real time or on the fly detection

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 processing a dead pixel, comprising:

a horizontal dead pixel detection module, said horizontal dead pixel detection module determining if a base pixel is a dead pixel by comparing said base pixel with at least one pixel adjacent to said base pixel in the same row, said horizontal pixel detection module referencing dead pixel by a pixel flag to generate a corrected pixel data, said corrected pixel data including said pixel flag;

a memory, said memory storing the corrected pixel data; and

a vertical dead pixel processing module, said vertical dead pixel processing module comparing a sum of a plurality of pixel flags included in a predetermined size of corrected pixel data block outputted from said memory with a first threshold value, said vertical dead pixel processing module replacing the original pixel data located in said predetermined size of corrected pixel data block with compensated pixel data in accordance to the result from said comparison of the sum of said plurality of pixel flags with the first threshold value.

2. The apparatus of claim 1, wherein the horizontal dead pixel detection module comprises:

a pixel data storage component, said pixel data storage component storing a series of original pixel data including a base pixel data;

a horizontal dead pixel detection component, said horizontal dead pixel detection component comparing the base pixel data with neighboring same-kind pixel data, said horizontal dead pixel detection component generating a dead pixel detection signal if the base pixel data is determined to be a dead pixel;

a frequency detection component, said frequency detection component comparing differences between a plurality of same-kind pixel data with a second threshold value, said frequency detection component generating a frequency bypass flag in accordance to said comparison of the differences between the same-kind pixel data with the second threshold value;

a pattern detection component, said pattern detection component comparing differences between the base pixel data and neighboring pixel data with a third threshold value, said pattern detection component generating a pattern bypass flag in accordance to said comparison of the differences between the base pixel data and the neighboring pixel data with the third threshold value; and

a reference signal generating component, said reference signal generating component generating the pixel flag corresponding to a predetermined instructions based upon conditions of a combination of the frequency bypass flag and the pattern bypass flag.

3. The apparatus of claim 2, wherein the first threshold value through the third threshold value are adjustable.

4. The apparatus of claim 2, wherein the operation of the frequency detection component and the pattern detection component is determined by predetermined operation selection data.

5. The apparatus of claim 1, wherein the vertical dead pixel processing module comprises:

a vertical dead pixel detection component, said vertical dead pixel detection component calculating a sum of a plurality of pixel flags of corrected pixel data groups located in at least one line having an angular relationship with a horizontal line of the corrected pixel data in the predetermined size of said corrected pixel data block and said vertical dead pixel detection component generating a dead pixel bypass signal by comparing said sum of said pixel flags with the first threshold value;

a pixel compensation component, said pixel compensation component generating the compensated pixel data; and

a multiplexer, said multiplexer selecting and outputting one of the original pixel data and the compensated pixel data in accordance with the dead pixel bypass signal.

6. The apparatus of claim 5, wherein the sum is calculated by multiplying different weighted values to a plurality of pixel flags.

7. An apparatus for processing a dead pixel, comprising:

a vertical dead pixel detection component, said vertical dead pixel detection component generating a dead pixel bypass signal in accordance with a comparison result between a sum and a threshold, the sum being calculated by adding pixel flags from each of a plurality of lines having an angular relationship with a horizontal line of a predetermined size of block of corrected pixel data, the corrected pixel data being coupled to an original pixel data by said each pixel flag that can identify a normal pixel and a dead pixel;

a pixel compensation component, said pixel compensation component generating compensated pixel data by use of a plurality of same-kind pixel data belonging to the predetermined size of the corrected pixel data block; and

a multiplexer, said multiplexer selecting and outputting one from a group consisting of the original pixel data and the compensated pixel data in accordance with the dead pixel bypass signal.

8. The apparatus of claim 7, wherein said each line of said plurality of the lines has different angular relationship with said horizontal line.

9. The apparatus of claim 8, wherein the sum is calculated by applying a same weighted value to a plurality of pixel flags if the angular relationship is a multiple of 45 degrees.

10. The apparatus of claim 8, wherein the sum is calculated by applying different weighted values to the plurality of pixel flags if the angular relationship is not a multiple of 45 degrees.

11. The apparatus of claim 7, wherein the predetermined size of the corrected pixel data block is N×

N and N is an odd number.

12. An apparatus for processing a dead pixel, comprising:

means for determining if a base pixel is a dead pixel by comparing said base pixel with at least one pixel adjacent to said base pixel in the same row, said means for determining if a base pixel is a dead pixel referencing a dead pixel by a pixel flag to generate a corrected pixel data, said corrected pixel data including the pixel flag;

a memory, said memory storing the corrected pixel data; and

means for comparing a sum of a plurality of pixel flags included in a predetermined size of corrected pixel data block outputted from said memory with a first threshold value, said means for comparing the sum of said plurality of pixel flags with said first threshold replacing the original pixel data located in said predetermined size of corrected pixel data block with compensated pixel data in accordance to the result from said comparison of the sum of said plurality of said pixel flags with the first threshold value.

13. An apparatus for processing a dead pixel, comprising:

means for generating a dead pixel bypass signal in accordance to result from comparison of a sum with a threshold value, said sum being calculated by adding pixel flags from each of a plurality of lines having an angular relationship with a horizontal line of a predetermined size of block of corrected pixel data, the corrected pixel data including said pixel flag that is indicative of a dead pixel;

means for generating compensated pixel data by use of a plurality of same-kind pixel data belonging to the predetermined size of the corrected pixel data block; and

a multiplexer, said multiplexer selecting and outputting one of the original pixel data and the compensated pixel data in accordance with the dead pixel bypass signal.

14. An apparatus for processing a dead pixel, comprising:

a horizontal dead pixel detection module, said horizontal dead pixel detection module identifying dead pixels row by row, said horizontal dead pixel detection module generating corrected pixel data by referencing said dead pixel with a pixel flag, said pixel flag being coupled to said corrected pixel data;

a line memory, said line memory storing said corrected pixel data; and

a vertical dead pixel processing module, said vertical dead pixel processing module comparing a sum of pixel flags belonging to an N×

N corrected pixel data block outputted from the line memory with a first threshold value, said vertical dead pixel processing module replacing the original pixel data located in the center of the N×

N corrected pixel data block with compensated pixel data in accordance to the result from comparison of the sum of pixel flags and the first threshold value.

15. The apparatus of claim 14, wherein the vertical dead pixel processing module comprises:

a vertical dead pixel detection component, said vertical dead pixel detection component calculating a sum of pixel flags of corrected pixel data groups occupied by a line having a different slope among the corrected pixel data belonging to the N×

N corrected pixel data block, said vertical dead pixel detection component generating a dead pixel bypass signal in accordance with a comparison result between the sum and the first threshold value;

a pixel compensation component, said pixel compensation component generating compensated pixel data by use of a plurality of same-kind pixel data belonging to the N×

N corrected pixel data block; and

a multiplexer, said multiplexer selecting and outputting one from a group consisting of the original pixel data and the compensated pixel data in accordance with the dead pixel bypass signal.