Shuguang Zhao Jun Zhao Yuan Wang Xinlin Fu Moving Object Detecting Using Gradient Information, Three-Frame-Differencing and Connectivity Testing. 510-518 2006 conf/ausai/2006 Australian Conference on Artificial Intelligence http://dx.doi.org/10.1007/11941439_55 db/conf/ausai/ausai2006.html#ZhaoZWF06