Cascade coding for subbit image compression
Marcos C. Tzannes, Alexis P. Tzannes, NICOLAOS S. TZANNES · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1990
"Cascade coding," a technique of double coding an image is introduced in this paper. Blocks of the image are first transform-coded and the retained coefficients of the transform are then quantized by a Block Truncation Coding C BTC) algorithm for transmission or storage. Upon reception or recall, the quantized transform coefficients are used in the inverse transform to reconstruct the image. The new method combines the spatial correlation characteristics of the transform methods with the ease of implementation of the BTC. Illustrations presented here on sub-bit image coding, shows it to perform consistently better than straight Cosine Transform (DCI') coding.