Two-pass hexagonal algorithm with improved hashtable structure for motion estimation

This paper presents an improved two-pass hexagonal (TPA) algorithm constituted by linear hashtable motion estimation algorithm (LHMEA) and hexagonal search (HEXBS) for motion estimation. In the TPA, motion vectors (MV) are generated from the first-pass LHMEA and are used as predictors for second-pass HEXBS motion estimation, which only searches a small number of macroblocks (MBs). The hashtable structure of LHMEA is improved compared to the original TPA and LHMEA. The evaluation of the algorithm considers the three important metrics being processing time, compression rate and PSNR. The performance of the algorithm is evaluated by using standard video sequences and the results are compared to current algorithms.