ORTHOGONAL TRANSFORMATION AND INVERSE ORTHOGONAL TRANSFORMATION DEVICE FOR ARBITRARY SHAPE IMAGE

摘要

PROBLEM TO BE SOLVED: To conduct orthogonal transformation or inverse orthogonal transformation for an arbitrary shape image more simply while reaching a coding rate nearly equal to that of a conventional method by segmenting an image area into rectangles and applying extrapolation when the coded object area obtained as a result has an arbitrary shape. SOLUTION: An extrapolation section 11 uses shape information to apply extrapolation to a received arbitrary shape area to generate a rectangular area. The shape information is generated by a shape information generating section and coded by a shape information coding section. An orthogonal transformation section 12 transforms a rectangular image obtained by the extrapolation section 11 by a conventional orthogonal transformation method. As the orthogonal transformation method, DCT or weblet transformation or the like is employed. A transformation coefficient after orthogonal transformation is coded by a transformation coefficient coding section. According to the image coding method, the orthogonal transformation is applied to an arbitrary area and the equipment is simplified by having only to add the extrapolation section 11 in front of the orthogonal transformation section for a rectangular area in the conventional method.