Towards a world standard for still image transmission

Over the past few years there has been growing interest in the transmission of still pictures in digital form. However, to achieve compatibility with CCIR recommendation 601 for a 625 line 4:2:2 component coded television picture sampled at 13.5 MHz, it is necessary to transmit some 828 kbytes of data for a full frame. Comparison with a teletext page requiring only one kbyte of data highlights the need for some form of image compression if a reasonable compromise between images and text is to be realised for data broadcasting. A close parallel exists in line transmission, where there is a requirement to transmit pictures employing similar standards over the Integrated Services Digital Network (ISDN) at a rate of 64 kbits/sec