IMAGE CODER, ITS METHOD, IMAGE DECODER, ITS METHOD AND PROVIDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To retrieve an optimum class code by applying nonlinear ADRC processing to a pixel value of a class tap by extending the retrieval range of the class code. SOLUTION: A pixel value update circuit 6 uses an original image and a prediction coefficient to update values of pixels of a high-order layer image. A prediction coefficient update circuit 7 uses pixel values of the high-order layer image and pixel values of the original image, to generate a prediction coefficient, which is outputted to prediction coefficient memory 4. A class code selection circuit 8 causes the classification information of pixels of the high-order layer image to change so as to retrieve an optimum class code for a target pixel and to output classification information corresponding to the optimum class code.