Patent ID: 8300956
Filing Date: 2012-10-30
Classification: H04N

Abstract:
1. A method of compressing a digital continuous tone image of pixels situated on scan lines, each pixel having a pixel value defined by at least one color channel value, a color channel value having B bits of precision (B>1), the method producing compressed image data and, for a current pixel to be encoded, said current pixel having an actual pixel value, said method comprising the steps of: predicting a predicted pixel value based on pixel values of at least one previously processed pixel from the same image, using a fixed rule; determining a difference parameter based on a difference value of said predicted pixel value and the actual pixel value of said current pixel to be encoded; inspecting the difference parameter for existence of an uninterrupted series of highest order bits having a value equal to zero; and removing at least part of said highest order zero bits, and, if a number of bits within predetermined limits remains, generating a compression code having a predetermined fixed length, said code being selected from a predetermined set of compression codes based on the number of remaining non-zero bits.