Patent ID: 7420709

Claim:
A method for generating a dither matrix for converting a gray scale image having N gray levels into a halftone image, comprising: using a parametric filter to generate a dither halftone pattern for each gray level G i >G t , where N>2, G t represents a transition gray level, the lightest gray level is G0, the darkest gray level is G N−1 , and G t· ≧G 0 , the parametric filter based upon a desired spot profile function of the halftone image, wherein the spot profile function is f Gi (X); and, the parametric filter is F Gi (x)=(1−α)*(log f Gi (x)/log f Gi (0) )+αe −x2 , where αε[0,1], α is a parameter that represents a trade-off between uniform dot growth and optimum halftone statistics as defined by the spot profile function f Gi (x), and x represents units of average inter-minority pixel distance X; and, using the generated dither halftone pattern to generate the dither matrix.