Highly efficient still image compression for data broadcasting

The large data content associated with high resolution natural still images has traditionally made their transmission on low to medium bandwidth channels time consuming if not impractical. By employing appropriate digital image compression techniques, the redundancy of such images can be exploited to significantly reduce bandwidth requirements. The ADCT (adaptive discrete cosine transform) algorithm, has been selected from a wide class of competing algorithms as offering best compression performance over a wide range of operating conditions. Low cost implementation will be supported by high density VLSI technology. The mechanism by which this algorithm achieves its high compression gain has been explored, and a number of experimental results presented. Given the particular characteristics of a broadcast channel, the need is established for careful consideration of error control coding in order to maintain compression efficiency. Applications which benefit from this technology include teletext, satellite news gathering and point-of-sale advertising