Patent ID: 7876972

Claim:
A method for filtering a noisy pixel comprising: a) selecting a set of pixels neighboring the noisy pixel; b) determining if the noisy pixel is a defective pixel, and if defective, then correcting by performing at least the following calculating an absolute value in differences of intensity for pairs of neighboring pixels, comparing the absolute values to a threshold, excluding a presence of each defective pixel when no more than one of the absolute values is larger than the threshold, otherwise deciding whether or not there is a defective pixel as a function of the comparing, selecting eight peripheral pixels and a central pixel of the image with the set of pixels comprising the eight peripheral pixels, deciding if the central pixel is defective by performing at least the following i) correcting each defective peripheral pixel by substituting its intensity based upon an intensity of at least one of its neighboring pixels, or by substituting intensities of two pixels used for identifying a largest absolute value of the differences of the two pixels used, ii) deciding which among the intensities of the central pixel or of a noise affected version thereof is closest to the intensities of the corrected peripheral pixels, iii) if the noise affected version has been chosen, verifying whether it is darker than a darkest of the corrected peripheral pixels or brighter than a brightest of the corrected peripheral pixels, respectively, iv) if the condition at the previous point is verified, then identifying the central pixel as a defective pixel, and v) correcting the central pixel if defective by substituting its intensity with the intensity of the corrected version of one of the peripheral pixels belonging to the set of pixels or with a combination of the intensities thereof; c) assigning a weight to each neighboring pixel as a function of the absolute value of the difference between its intensity and the pixel intensity chosen in step iv); and d) generating the intensity of a corrected and noise filtered replica of the noisy pixel as the weighted sum of the intensities of the neighboring pixels, weighted with the weights, and the intensity of the noisy pixel weighted with the largest of the weights.