Forward Adaptive Laplacian Source Coding Based on Restricted Quantization

  • Bojan Denic University of Nis, Faculty of Electronic Engineering
  • Zoran Peric University of Nis, Faculty of Electronic Engineering
  • Vladimir Despotovic University of Belgrade, Technical Faculty of Bor
  • Nikola Vucic University of Nis, Faculty of Electronic Engineering
Keywords: restricted scalar quantization, switched quantization, Lloyd-Max’s algorithm, Huffman code, forward adaptation


A novel solution for Laplacian source coding based on three-level quantization is proposed in this paper. The restricted three-level quantizer is designed by assuming the restricted Laplacian distribution of the input signal. Quantizer and Huffman encoder are jointly designed. Forward adaptive scheme was employed, where the adaptation to the signal variance (power) was performed on frame-by frame basis. We employ switched model that consists of two restricted quantizers having unequal support regions. The simulation results (measured as SQNR) of the proposed scheme with a switched restricted three-level quantizer are compared to the cases when it involves three-level unrestricted quantizer and the Lloyd-Max quantizers having N=2 and N=4 levels. It is shown that the proposed solution offers performance comparable to the one of N=4 levels Lloyd-Max’s baseline with large savings in bit rate, while outperforming two other baselines.