Two-stage hierarchical search and motion vector smoothing in motion estimation
Long-Wen Chang, Jiunn Y. Ho · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1993
Motion estimation is very important in video-phone, video-conference and HDTV, which will become part of everyday life in the near future. Conventionally, it uses full search algorithm because of its computational regularity suitable for VLSI implementation. However, its search range around the search center is 16 X 16 pixels, which requires 256 processors. To increase the search range by full search for HDTV applications, the number of processors will also increase. This makes it very difficult for VLSI implementation. This paper proposes a two stage hierarchical search algorithm to overcome the difficulty. In the first stage, k best motion vectors are found and then fine tuned in the second stage. Both stages use full search and can be easily implemented by VLSI. Instead of using multi-layers hierarchical search technique, we propose a two stage hierarchical search algorithm. It does not require sampling process and can be implemented in a much simpler hardware circuit.