A recently introduced tree growth algorithm the Marginal Returns (MR) algorithm is used to grow multiple rate tree structured vector quantizers for the pyramid coding of hexagonally sampled images. The use of a structured multi-rate code book solves two problems that normally arise in vector quantization of subbands. The multiple rate code book can operate over a wide range of rates thus dispensing with the need to transmit the code book as overhead while the tree structure reduces the search complexity. Search complexity is a crucial issue even in low rate pyramid coding since subbands with more information content are coded at high rates. In addition the design technique makes it possible to tune the coder to the spectral properties of the image by optimally allocating rate to the different subbands. It has been shown in an earlier paper that the Marginal Returns algorithm yields code books that are optimal for sources that meet the law of diminishing marginal returns. However even for sources that do not satisfy these conditions the algorithm gives coders that perform close to the optimal. Image coding results at rates below 1 bpp are presented.

Date Published: 1 November 1990
PDF: 10 pages
Proc. SPIE 1349, Applications of Digital Image Processing XIII, (1 November 1990); doi: 10.1117/12.23570

Published in SPIE Proceedings Vol. 1349:
Applications of Digital Image Processing XIII
Andrew G. Tescher, Editor(s)