Patent ID: 6806902
Filing Date: 2004-10-19
Classification: H04N

Abstract:
A bad pixel detection and correction system, comprising:a plurality of line memories configured to store a like plurality of lines of digital pixel data values from a photocell array; a computing circuit configured to: dynamically compute in real time first and second estimates for the value of a given pixel from the values of surrounding pixels, the values of the given pixel and the surrounding pixels comprising pixel data output from the line memories and the photocell array, wherein the first estimate is a dynamically determined minimum value and the second estimate is a dynamically determined maximum value; and limit the value of the given pixel to a corrected value within a range defined by the dynamically determined minimum and maximum values; the computing circuit comprising; gradient circuitry that computes vertical and horizontal gradients of the surrounding pixels immediately above and below and to the left and right of the given pixel; estimate circuitry that computes four estimates of the value of the given pixel by respectively adding and subtracting the vertical and horizontal gradients from values of the surrounding pixels of the same color as the given pixel that are above and below and to the left and right of the given pixel; min and max circuitry that computes the minimum and the maximum values by respectively determining the smallest and the largest of the four estimates; and limiting circuitry that sets the corrected value to the minimum value when the value of the given pixel is less than the minimum value, sets the corrected value to the maximum value when the value of the given pixel is greater than the maximum value, and otherwise sets the corrected value to the given pixel value; and a plurality of pixel delay elements configured to store the values of the given pixel and the surrounding pixels.