Method for concealing dark defect in image sensor

Abstract

Disclosed is a method for concealing a dark defect in an image sensor. The method includes the steps of: setting a window including five sequential pixels from pixel data sequentially outputted, the third pixel and the fifth pixels being identical in Bayer color with each other and the second and the fourth pixels being identical in Bayer color with each other; calculating an average value α of the first and the fifth pixels and a plurality of α/n obtained by dividing the average value α by n; selecting one of the plurality of α/n; comparing a threshold value α+α/n calculated by adding the average value α to the selected α/n with a value of the third pixel in size; and omitting a concealment of the dark defect when the threshold value α+α/n is greater than the value of the third pixel.

1. A method for concealing a dark defect in an image sensor, comprising the steps of:
 setting a window including five sequential pixels, a first pixel P 1 , a second pixel P 2 , a third pixel P 3 , a fourth P 4  and a fifth pixel P 5 , from a plurality of pixel data sequentially outputted, the third pixel and the fifth pixels P 3  and P 5  being identical in Bayer color with each other and the second and the fourth pixels P 2  and P 4  being identical in Bayer color with each other; 
 calculating an average value ‘α’ of the first and the fifth pixels P 1  and P 5  and a plurality of ‘α/n’ obtained by dividing the average value ‘α’ by ‘n’, ‘n’ being a multiple of 2; 
 selecting one of the plurality of ‘α/n’; 
 comparing a threshold value ‘α+α/n’ calculated by adding the average value ‘α’ to the selected ‘α/n’ with a value of the third pixel P 3  in size; and 
 omitting a concealment of the dark defect in the image sensor when the threshold value ‘α+α/n’ is greater than the value of the third pixel P 3 . 
 
     
     
       2. The method of  claim 1 , wherein further including a step of judging whether the edge exists or not within the window by the comparison result. 
     
     
       3. The method of  claim 2 , wherein in the step of judging the edge, the concealment of the dark defect is omitted when the comparison result represents the existence of the edge within the window. 
     
     
       4. The method of  claim 3 , wherein if one of conditions of |P 2 −P 4 |>(P 2 +P 4 )/2 and |P 1 −P 5 |>(P 1 +P 5 )/4 is satisfied, it is judged that the edge exists within the window. 
     
     
       5. The method of  claim 4 , wherein even though the edge exists within the window by satisfying one of the conditions of |P 2 −P 4 |>(P 2 +P 4 )/2 and |P 1 −P 5 |>(P 1 +P 5 )/4, as the values of the first and the fifth pixels P 1  and P 5  are falling under a blocking zone having a less value than a predetermined value, the concealment of the dark defect is performed. 
     
     
       6. The method of  claim 5 , wherein the predetermined value ranges from approximately 7 to approximately 32 in case of a 255 code of an 8 bit. 
     
     
       7. The method of  claim 1 , wherein at the step of selecting one of the plurality of ‘α/n’, a detecting capability of the dark defect increases and an image quality degrades as a value of ‘n’ increases. 
     
     
       8. The method of  claim 1 , wherein the pixel data is comprised of a format of a red color (R), a green color (G) and a blue color (B). 
     
     
       9. A method for concealing a dark defect in an image sensor, comprising the steps of:
 extracting a window including five sequential pixels, a first pixel P 1 , a second pixel P 2 , a third pixel P 3 , a fourth P 4  and a fifth pixel P 5 , from a plurality of pixel data sequentially outputted, the third and the fifth pixels P 3  and P 5  being identical in Bayer color with each other and the second and the fourth pixels P 2  and P 4  being identical Bayer color with each other; 
 calculating an average value ‘α’ of the first and the fifth pixels P 1  and P 5  and a plurality of ‘α/n’ obtained by dividing the average value ‘α’ by ‘n’, ‘n’ being a multiple of 2; 
 selecting one of the plurality of ‘α/n’; 
 comparing a threshold value ‘α+α/n’ calculated by adding the average value ‘α’ to the selected ‘α/n’ with a value of the third pixel P 3  in size; 
 judging an existence of an edge within the window by using the comparison result; and 
 performing the concealment of the dark defect in the image sensor when the comparison result is affirmative. 
 
     
     
       10. The method of  claim 9 , wherein in the step of judging the existence of the edge in the window, the concealment of the dark defect with respect to the third pixel P 3  is performed as both of the first and the fifth pixels P 1  and P 5  are falling under a blocking zone having a value less than a predetermined value even though the edge exists in the window by satisfying one of conditions of |P 2 −P 4 |>(P 2 +P 4 )/2 and |P 1 −P 5 |>(P 1 +P 5 )/4. 
     
     
       11. The method of  claim 10 , wherein the predetermined value ranges from approximately 7 to approximately 32 in case of a 255 code of an 8 bit. 
     
     
       12. The method of  claim 9 , wherein at the step of selecting one of the plurality of ‘α/n’, a detecting capability of the dark defect increases and an image quality degrades as a value of n increases. 
     
     
       13. The method of  claim 9 , wherein the pixel data is comprised of a format of a red color (R), a green color (G) and a blue color (B). 
     
     
       14. A method for correcting pixel data in an image sensor, the method comprising:
 calculating a first threshold and a second threshold;   determining a luminance value of an image from the image sensor, wherein the image comprises a first pixel having a first pixel value, a second pixel having a second pixel value, and a third pixel having a third pixel value;   selecting one of the first threshold and the second threshold to form a selected threshold according to the luminance value; and   concealing a dark defect in the image sensor if the second pixel value is greater than the selected threshold.   
     
     
       15. The method of claim 14, further comprising:
 judging an existence of an edge in the window; and   omitting the step of concealing a dark defect if the edge exists.   
     
     
       16. The method of claim 14, wherein each of the first threshold and the second threshold are proportional to an average value of the first pixel value and the third pixel value. 
     
     
       17. The method of claim 14, wherein the first pixel and the second pixel are separated by a pixel having a different color; and
 wherein the second pixel and the third pixel are separated by another pixel having a different color.   
     
     
       18. A method for correcting pixel data in an image sensor, the method comprising:
 calculating a first threshold and a second threshold;   wherein the first threshold and the second threshold are each proportional to an average value of a first pixel value and a third pixel value;   selecting one of the first threshold and the second threshold to form a selected threshold; and   concealing a dark defect in the image sensor if a second pixel value is greater than the selected threshold;   wherein each of the first pixel value, the second pixel value, and the third pixel value are representative of a first color.   
     
     
       19. The method of claim 18, further comprising:
 determining a luminance of an image comprising the first pixel value, the second pixel value, and the third pixel value; and   wherein the step of selecting one of the first threshold and the second threshold is performed according to the luminance.