Optimized Predictive Zonal Search (OPZS) for block-based motion estimation

Predictive Motion Estimation (ME) techniques are fast ME algorithms that have been widely used in video CODECs due to their performance efficiency and low computational complexity. In this paper, a new approach named Optimized Predictive Zonal Search (OPZS) is proposed, which improves the state-of-the-art Enhanced Predictive Zonal Search (EPZS) algorithm. The new initial predicted motion vectors employ fewer, but more optimized predictors, as well as improve the termination procedure. The proposed OPZS not only achieves better output quality and significantly higher compression ratio, but also reduces the number of search points and ME processing time even further. Simulation results after encoding 6 different video test sequences with OPZS along with EPZS and three other algorithms implemented under the same conditions has shown up to 33% compression ratio enhancement. This is achieved by searching up to 14% less points, which means less computational complexity and up to 0.4 dB higher PSNR values. The simplicity and high performance of OPZS make it more practical for implementation on both hardware and software platforms. Since OPZS provides a combination of low computational complexity and high quality encoded images, it is energy efficient and suitable for portable video processing in computation- or power-constrained applications. Furthermore, because of the higher compression ratio this newly proposed algorithm is more compatible with limited capacity storage media and transmission networks with limited band-width.