Weiyao Lin Ming-Ting Sun Radha Poovendran Zhengyou Zhang Group Event Detection for Video Surveillance. 2830-2833 2009 ISCAS http://dx.doi.org/10.1109/ISCAS.2009.5118391 conf/iscas/2009 db/conf/iscas/iscas2009.html#LinSPZ09