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Proceedings Paper

Hierarchical Picture Coding Using Quadtree Decomposition
Author(s): Yves Buhler; Michel Fortier
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Paper Abstract

A new hierarchical encoding scheme for grey-level pictures is presented here. The picture field is split by a modified quadtree algorithm into blocks of size 32 x 32, 16 x 16, 8 x 8 and 4 x 4 pels, according to their subjective importance in the picture. The larger cells, of size 32 x 32, 16 x 16 and 8 x 8 pels, corresponding to uniform or low-detailed areas, are coded at a very low rates by block truncation in the Discrete Cosine Transform field. The smallest blocks, representing mainly high-detailed areas of the like edges or textures are coded with a multi-codebook vector quantization scheme. Due to its structure, such an encoding scheme is especially well adapted for coding "head and shoulders" pictures, mostly encountered in videophone or videoconference application, where large areas of background may appear. Concerning the vector quantization, several techniques were investigated in order to improve the subjective quality and to reduce the search time through the codebooks. This permits a faster elaboration of the codebooks. Results are presented with bit-rates ranging from 0.4 to 0.8 bits/pel depending on the picture complexity.

Paper Details

Date Published: 14 October 1987
PDF: 8 pages
Proc. SPIE 0804, Advances in Image Processing, (14 October 1987); doi: 10.1117/12.941332
Show Author Affiliations
Yves Buhler, INRS-Telecommunications (Canada)
Michel Fortier, INRS-Telecommunications (Canada)


Published in SPIE Proceedings Vol. 0804:
Advances in Image Processing
Andre J. Oosterlinck; Andrew G. Tescher, Editor(s)

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