TAT SYSTEM FOR HIGH QUALITY IMAGE COMPRSSION.

The TAT (time-axis transform) system is an image compression system which reduces the pixels selectively from the nondetail portions of the picture. The pixels can be reduced to one half or less, keeping high resolution in the detail portions. Thus, TAT is suitable for the compression of high-quality images. It can be applied to both analog and digital systems. A 2-D TAT system using two-dimensional correlation is implemented and compression experiment is conducted. A high-quality picture signal with a bandwidth of 7 MHz is compressed to 3. 5 MHz. Performance for both still and moving pictures is good. The difference between the reconstructed and the original pictures is hardly observed. Thus, the feasibility and effects of the TAT system is verified. Furthermore, the simulation experiment of the 3-D-TAT using three-dimensional correlation is made for the HDTV signal. A mode decision algorithm of the four-mode TAT is developed and the HDTV compression to a bandwidth of 8 MHz is successfully demonstrated.