Instructor: Professor Yu Hen Hu An Investigation of Hardware Implementation for Block Based Motion-Estimation Algorithm. ECE734/Spring 2002 Instructor: Professor Yu Hen Hu By Sarawadee Krepanith

Motivation The main purpose of video coding is to reduce the bit rate by removing the redundant information DCT for the reduction of spatial redundancy Block-based motion compensation for the reduction of temporal redundancy

Block Matching Algorithm Full search based block matching method is computationally very expensive, but give fairly accurate results. There are others search methods that propose which are faster at the expense of accuracy. Examples are three step search, 2-D logarithmic search, the conjugate search, etc.

Three-Step Hierarchical Search Find a best matched displaced block from the previous frame Ft-1 within the search range for each NxN block in the present frame Ft In Full Search, matched all possible candidates exhaustively to find the motion vector with minimal distortion Mean Absolute Difference (MAD) is used as criteria

Three-Step Hierarchical Search Search for the best motion vector in the coarse-to-fine manner First step, nine candidates are evaluated Second and third steps, the distances between candidates are shortened

Challenging Motion estimation is the bottleneck step in video coding as it requires most processing power Many hardware implementations have been proposed Comparison in various aspect will be delivered