VERFAHREN ZUR AUFBEREITUNG VON BILDDATEN, INSBESONDERE FUER STANDBILDUEBERTRAGUNGSZWECKE

摘要

To process picture data, especially for still picture transmission, picture data are in each case transformation-coded by sub-picture areas in a plurality of passes and the coefficients obtained are selected for transmission according to their significance. In each pass, finer quantisation and selection of a larger number of coefficients are carried out. The picture data obtained from each pass of the processing are used to process subsequent pictures if the content of the subsequent pictures has changed only slightly compared with the previously processed picture. The DC coefficients already undergo definitive fine quantisation in the first pass and are not further improved in the subsequent passes. <IMAGE>