Guangtao Zhai Jianfei Cai Weisi Lin Xiaokang Yang Wenjun Zhang Image deringing using quadtree based block-shift filtering. 708-711 2008 ISCAS http://dx.doi.org/10.1109/ISCAS.2008.4541516 conf/iscas/2008 db/conf/iscas/iscas2008.html#ZhaiCLYZ08