Asymmetrical two-level scalar quantizer with extended Huffman coding for compression of Laplacian source

TL;DR

This paper introduces an asymmetrical two-level scalar quantizer combined with extended Huffman coding for efficient compression of Laplacian sources, achieving near-entropy bit rates with minimal SQNR loss.

Contribution

It presents a novel asymmetrical quantizer design with extended Huffman coding that closely approaches source entropy while maintaining high SQNR for Laplacian signals.

Findings

Higher SQNR compared to symmetrical quantizers.

Average bit rate converges to source entropy for block sizes of 2 to 5.

Effective lossless compression with minimal SQNR degradation.

Abstract

This paper proposes a novel model of the two-level scalar quantizer with extended Huffman coding. It is designed for the average bit rate to approach the source entropy as close as possible provided that the signal to quantization noise ratio (SQNR) value does not decrease more than 1 dB from the optimal SQNR value. Assuming the asymmetry of representation levels for the symmetric Laplacian probability density function, the unequal probabilities of representation levels are obtained, i.e. the proper basis for further implementation of lossless compression techniques is provided. In this paper, we are concerned with extended Huffman coding technique that provides the shortest length of codewords for blocks of two or more symbols. For the proposed quantizer with extended Huffman coding the convergence of the average bit rate to the source entropy is examined in the case of two to five symbol blocks. It is shown that the higher SQNR is achieved by the proposed asymmetrical quantizer with extended Huffman coding when compared with the symmetrical quantizers with extended Huffman coding having equal average bit rates.