An adaptive interframe transform coding system for images

An adaptive interframe coding system for monochrome pictures is described, which uses the three-dimensional discrete cosine transform. Based on three-dimensional classification the coder is matched according to the amount of detail and the predominant direction of the structure within a transform block. The distinction between temporally changed and unchanged blocks enables coding of still blocks with an alternative algorithm. This algorithm increases the reconstruction quality for still pictures, making possible a transmission of graphs with good resolution. Simulation results are presented for a moving picture at a rate of 0.4 bit per element and still grey and black-and-white pictures with increasing quality.