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Proceedings Paper

Haar wavelet processor for adaptive on-line image compression
Author(s): F. Javier Diaz; Angel M. Buron; Jose M. Solana
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Paper Abstract

An image coding processing scheme based on a variant of the Haar Wavelet Transform that uses only addition and subtraction is presented. After computing the transform, the selection and coding of the coefficients is performed using a methodology optimized to attain the lowest hardware implementation complexity. Coefficients are sorted in groups according to the number of pixels used in their computing. The idea behind it is to use a different threshold for each group of coefficients; these thresholds are obtained recurrently from an initial one. Parameter values used to achieve the desired compression level are established "on-line", adapting their values to each image, which leads to an improvement in the quality obtained for a preset compression level. Despite its adaptive characteristic, the coding scheme presented leads to a hardware implementation of markedly low circuit complexity. The compression reached for images of 512x512 pixels (256 grey levels) is over 22:1 (≈0.4 bits/pixel) with a rmse of 8-10%. An image processor (excluding memory) prototype designed to compute the proposed transform has been implemented using FPGA chips. The processor for images of 256x256 pixels has been implemented using only one general-purpose low-cost FPGA chip, thus proving the design reliability and its relative simplicity.

Paper Details

Date Published: 30 June 2005
PDF: 9 pages
Proc. SPIE 5837, VLSI Circuits and Systems II, (30 June 2005); doi: 10.1117/12.608261
Show Author Affiliations
F. Javier Diaz, Univ. of Cantabria (Spain)
Angel M. Buron, Univ. of Cantabria (Spain)
Jose M. Solana, Univ. of Cantabria (Spain)

Published in SPIE Proceedings Vol. 5837:
VLSI Circuits and Systems II
Jose Fco. Lopez; Francisco V. Fernandez; Jose Maria Lopez-Villegas; Jose M. de la Rosa, Editor(s)

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