Patent ID: 7024049

Claim:
A method for improving appearance of captured bilevel image data, comprising: receiving a degraded input bilevel image; connecting dark pixels in the input image to adjacent dark pixels to form connected components comprising a set of dark pixels connected either diagonally or orthogonally and surrounded by white pixels; performing initial clustering of individual connected components; determining a “most likely” cluster representative by use of a probabilistic model of the scanner used for scanning; and assembling the sets by substituting the “most-likely” cluster representative for each family member of each cluster set to form an output image, wherein the step of performing initial clustering includes pair-wise matching connected components and determining a match if the pair are within a certain threshold of matching to form cluster sets, each with one or more family members formed of individual connected components, the step of determining a “most likely” cluster representative for each cluster set uses a optimization procedure in which at least one iteration of pixel flipping is performed, multiple iterations of pixel flipping are performed, with a first iteration of pixel flipping being performed with a first threshold, and a subsequent iteration being performed with a more progressive threshold being applied until a maximized probability is attained.