Adaptive image-smoothing using a coplanar matrix and its application to document image binarization.

Lixin Fan Liying Fan Chew Lim Tan Adaptive image-smoothing using a coplanar matrix and its application to document image binarization. 88-101 2003 5 IJDAR 2-3 http://dx.doi.org/10.1007/s10032-002-0098-0 db/journals/ijdar/ijdar5.html#FanFT03