Xiao Wu Yongdong Zhang Yufeng Wu Junbo Guo Jintao Li Invariant visual patterns for video copy detection. 1-4 2008 ICPR http://dx.doi.org/10.1109/ICPR.2008.4761421 conf/icpr/2008 db/conf/icpr/icpr2008.html#WuZWGL08