Method for correcting a defect pixel
View Patent ↗A method for correcting a defect pixel includes extracting a pixel value of a central pixel, and pixel values of each of a plurality of neighboring pixels around the central pixel in an image sensor by using a color filter; calculating reference levels by multiplying each the pixel value of the plurality of neighboring pixels by a weight value; calculating a total number of cases where the pixel value of the central pixel is larger or smaller than the reference level as a first comparison value or second comparison value, respectively; determining the central pixel is a defect pixel where the first or second comparison value is larger than a first or second control register value, by comparing the comparison values with the control register values, respectively; and correcting the central pixel determined as the defect pixel.
1. A method for correcting a defect pixel, the method comprising:
extracting a pixel value of a central pixel, and pixel values of each of a plurality of neighboring pixels around the central pixel in an image sensor, by using a color filter;
calculating reference levels by multiplying each the pixel value of each of the neighboring pixels by a weight value;
calculating a total number of cases where the pixel value of the central pixel is larger than each of the reference levels as a first comparison value, and a total number of cases where the pixel value of the central pixel is smaller than each of the reference levels, as a second comparison value, by comparing each of the calculated reference levels with the pixel value of the central pixel;
determining the central pixel is a defect pixel
where the first comparison value is larger than a first control register value, by comparing the first comparison value with the first control register value, or
where the second comparison value is larger than a second control register value, by comparing the second comparison value with the second control register value; and
correcting the central pixel determined as the defect pixel.
2. The method of claim 1 , wherein:
the correcting the central pixel comprises replacing the pixel value of the central pixel with an average pixel value of the plurality of neighboring pixels.
3. The method of claim 2 , wherein:
the correcting the central pixel further comprises determining whether or not each of the plurality of neighboring pixels is the defect pixel.
4. The method of claim 3 , wherein:
the determining whether or not each of the plurality of neighboring pixels is the defect pixel uses the same method as the determining the central pixel is a defect pixel.
5. The method of claim 4 , wherein:
the correcting the central pixel comprises replacing the pixel value of the central pixel with an average pixel value of the neighboring pixels which are not the defect pixel among the plurality of neighboring pixels.
6. The method of claim 1 , wherein:
the weight value is 1 to 15.
7. The method of claim 6 , wherein:
where the first comparison value is larger than the first control register value, the central pixel is determined as a hot pixel.
8. The method of claim 7 , wherein:
the first control register value is 5 to 7.
9. The method of claim 1 , wherein:
the weight value is 0.1 to 1.0.
10. The method of claim 9 , wherein:
where the second comparison value is larger than the second control register value, the central pixel is determined as a dead pixel.
11. The method of claim 10 , wherein:
the second control register value is 5 to 7.
12. The method of claim 1 , wherein:
the color filter is a filter in an n×n (n is an integer of 3 or more) matrix form comprising pixels having the same color in a Bayer pattern.