Edge-preserving prefiltering for document image binarization

Liying Fan, Chew Lim Tan, Lixin Fan

Abstract: We propose a novel coplanar filter, which exploits the coplanarity of the gray-level distribution of neighboring pixels, to pre-filter document images. Experiments show that the proposed filter exhibits the following desired properties for document image binarization: (1) impulsive noise removal; (2) piecewise smoothing; (3) sharp edge preservation.