A method for coding scanned documents containing halftonepictures, e.g. newspapers and magazines, for transmission purposes isproposed. The halftone screen is estimated and the grey value of eachdot is found, thus giving a compact description. At the receiver thepicture is rescreened. A novel data structure and related algorithms forhandling the digital screen without restrictions on the screenparameters is presented. Data compression rates above 20 are obtainedfor the halftone pictures. The algorithms are suited for implementationwith fast dedicated hardware. The rescreening can also be used asdigital halftoning with arbitrary screens, using lookup tables
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