Model-based/waveform hybrid coding for videotelephone images

An image coding method that combines model-based coding with conventional waveform coding is presented. Despite its potential to realize image communication at very low rates, model-based coding still has many glitches that need to be solved before any practical use. The major problems are the difficulty in modeling unknown objects and the presence of analysis errors. To cope with these difficulties, waveform coding is incorporated into model-based coding. The incorporated waveform coder can code unmodeled objects and cancel errors of the analysis system. A general model of model-based/waveform hybrid coding is discussed. Preliminary simulation results of a model-based/MC-DCT hybrid coding system show that this hybrid coding method is effective at very low transmission rates, such as 16 kb/s