METHOD FOR CODING IMAGE SIGNALS

摘要

For coding image signals, particularly for the colour transmission of individual images, spectral coefficients are formed by means of a DCT. The sensitivity of a perceptibility threshold decision arrangement applied to blocks of these spectral coefficients is controlled in dependence on the occurrence of edge structures in the image content. The threshold decision is followed by a quantisation and an entropy encoding. For the data reduction, classes are allocated block by block to the spectral coefficients. The transmission of a class information is sufficient for identifying the spectral coefficients for such classes.