[1] Univ Reading, Computat Vis Grp, Dept Comp Sci, Reading, Berks, England
[2] Chinese Acad Sci, Natl Lab Pattern Recognit NLPR, Inst Automat, Beijing, Peoples R China
[3] Chinese Acad Sci, Ctr Res Intelligent Percept & Comp CRIPAC, Beijing, Peoples R China
[4] Chinese Acad Sci, NLPR, Beijing, Peoples R China