Patent ID: 7907192

Claim:
A method for processing images captured by an image sensor having an array of pixels, the method comprising: (a) capturing a series of dark frames at a first time from substantially all of the pixels in the array and averaging the series of dark frames together to generate a baseline dark floor comprising first dark floor values; (b) capturing contemporary dark floor values from substantially all of the pixels in the array at another time subsequent to the first time; (c) using the first dark floor values and the contemporary dark floor values to compute adjusted dark floor values, wherein a gain function is determined at a plurality of specified pixel neighborhoods with the gain function expressed by an equation α = Σ ⁢ ⁢ X k 2 M k Σ ⁢ ⁢ M k ⁢ where: α is the gain function for a given pixel neighborhood, M k is the first dark floor value for the k th pixel in the given pixel neighborhood, and X k is the contemporary dark floor value for the corresponding k th pixel in the given pixel neighborhood; (d) using the adjusted dark floor values when processing one or more captured images; and (e) periodically repeating (b)-(d), wherein the same first dark floor values are used in (c) each time subsequent adjusted dark floor values are computed.