Table of Contents
ISRN Signal Processing
Volume 2011, Article ID 386128, 10 pages
http://dx.doi.org/10.5402/2011/386128
Research Article

A Fast Fractal Video Coding Algorithm Using Cross-Hexagon Search for Block Motion Estimation

1Department of Electronics, School of Engineering, University of Sidi Bel Abbès, Sidi Bel Abbès 22000, Algeria
2Department of Measurement Control & Information Technology, School of Instrumentation Science & Optoelectronics Engineering, Beihang University, Beijing 100191, China

Received 8 March 2011; Accepted 28 April 2011

Academic Editor: A. Ito

Copyright © 2011 Kamel Belloulata et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We propose a novel fractal video coding method using fast block-matching motion estimation to overcome the drawback of the time-consuming character in the fractal coding. As fractal encoding essentially spends most time on the search for the best-matching block in a large domain pool, search patterns and the center-biased characteristics of motion vector distribution have large impact on both search speed and quality of block motion estimation. In this paper, firstly, we propose a new hexagon search algorithm (NHEXS), and, secondly, we ameliorate, by using this NHEXS, the traditional CPM/NCIM, which is based on Fisher's quadtree partition. This NHEXS uses two cross-shaped search patterns as the first two initial steps and large/small hexagon-shaped patterns as the subsequent steps for fast block motion estimation (BME). NHEXS employs halfway stop technique to achieve significant speedup on sequences with stationary and quasistationary blocks. To further reduce the computational complexity, NHEXS employs modified partial distortion criterion (MPDC). Experimental results indicate that the proposed algorithm spends less encoding time and achieves higher compression ratio and compression quality compared with the traditional CPM/NCIM method.