Optimum bit rate pyramid coding with low computational and memory requirements

This paper presents the optimum bit allocation for fixed rate pyramid coding structures which use a lowpass filter with nominal bandwidth of π/4 for predecimation filtering. This technique results in about 32% less in the computational complexity and 20% less in the memory requirements than the conventional filters used for pyramid coding. Three different algorithms are introduced. In the first algorithm the decimated image is transmitted at 8 bpp and the difference image is DCT-encoded. In the second algorithm the decimated image is encoded using BTC and the difference image is DCT-encoded, while in the third algorithm the decimated image is BTC-encoded with further quantization of the DCT coefficients of the difference image. These algorithms achieve high compression rate and allow at the same time a low complexity encoder