TELEVISON RECEIVER WITH TELETEXT RECEIVING FUNCTION AND METHOD OF SUPERIMPOSING TELETEXT PICTURE ON TELEVISION PICTURE

摘要

In case teletext data superimposed on a television broadcast signal are to be displayed as an auxiliary picture on a main picture on which a television video signal is displayed, the teletext data must be compressed. If the logical outputs of two pixels themselves adjacent in the horizontal direction are made data after the compression as this compressing method, depending on the contents of the teletext data, the data after the compression will not reproduce the original information in some case. In this invention, the teletext data are divided into blocks of a predetermined size and the "dense" and "rare" densities of the respective blocks are judged. The optimum compressing method losing no information is selected in response to this judging result.