Dynamic identification and correction of defective pixels
First Claim
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1. A method of distinguishing high quality elements from defective elements in an array of photo-sensitive elements, the method comprising:
- calculating a plurality of difference values for a first element of the array of photo-sensitive elements by comparing the output of the first element to the outputs of a corresponding plurality of elements neighboring the first element;
determining whether the sign values of the plurality of calculated difference values fall within at least a first, second or third group wherein the first group being the sign values are all positive, the second group being the sign values are all negative, and the third group being the sign values are neither all positive nor all negative;
in response to a determination that the sign values of the plurality of difference values fall within the first and second groups comparing each of the plurality of difference values with at least one defect determination threshold, andin response to a determination that the sign values of the plurality of difference values fall within the third group identifying the first element to be of high quality.
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Abstract
Rather than storing a table within a digital camera or other optical device of defective pixels within its image sensor, defective pixels are dynamically identified by comparing the output values of individual pixels under test with those of neighboring pixels. If the neighbors are all above or below the pixel under test by a defined threshold amount, the output of the pixel under test is replaced with a value calculated from the outputs of neighboring pixels.
163 Citations
9 Claims
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1. A method of distinguishing high quality elements from defective elements in an array of photo-sensitive elements, the method comprising:
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calculating a plurality of difference values for a first element of the array of photo-sensitive elements by comparing the output of the first element to the outputs of a corresponding plurality of elements neighboring the first element; determining whether the sign values of the plurality of calculated difference values fall within at least a first, second or third group wherein the first group being the sign values are all positive, the second group being the sign values are all negative, and the third group being the sign values are neither all positive nor all negative; in response to a determination that the sign values of the plurality of difference values fall within the first and second groups comparing each of the plurality of difference values with at least one defect determination threshold, and in response to a determination that the sign values of the plurality of difference values fall within the third group identifying the first element to be of high quality. - View Dependent Claims (2, 3)
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4. A method of identifying and correcting defective ones of an array of photo-sensitive pixels, comprising:
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directing an object field of varying light intensity across the array; calculating a plurality of difference values for a first element of the array of photo-sensitive elements by comparing the output of the first element to the outputs of a corresponding plurality of elements neighboring the first element; determining whether the sign values of the plurality of calculated difference values fall within at least a first, second or third group wherein the first group being the sign values are all positive, the second group being the sign values are all negative, and the third group being the sign values are neither all positive nor all negative; in response to a determination that the sign values of the plurality of difference values fall within the first and second groups, performing a process including; determining whether one or more of the difference values are in excess of the threshold, in response to a determination of one or more of the difference values not exceeding the threshold, utilizing the output of the first pixel for data of the object field, and in response to a determination of all of the difference values exceeding the threshold, calculating a pixel value of the first pixel from at least some of the neighboring pixels and utilizing the calculated pixel value for data of the object field; and in response to a determination that the sign values of the plurality of difference values fall within the third group, utilizing the output of the first pixel for data of the object field without comparing the difference values with a defect determination threshold. - View Dependent Claims (5, 6, 7, 8, 9)
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Specification