Ishfaq Ahmad Weiguo Zheng Jiancong Luo Ming Lei Liou A fast adaptive motion estimation algorithm. 420-438 2006 16 IEEE Trans. Circuits Syst. Video Techn. 3 http://doi.ieeecomputersociety.org/10.1109/TCSVT.2006.870022 db/journals/tcsv/tcsv16.html#AhmadZLL06