Dual-binarization and anisotropic diffusion of Chinese characters in calligraphy documents

In this paper, we propose a method for calligraphy document binarization. First, the properties of calligraphy documents are analyzed to classify calligraphy documents into two classes: tablet documents and writing documents. Because calligraphy documents have serious noises and large variations in gray scales of the characters, the foreground will be broken after thresholding. The anisotropic diffusion technique is used to smooth input calligraphy documents, which can preserve character boundaries well. Last, noises are removed from binarized images based on the information of stroke widths. In our experiments, 90 tablet documents and 51 writing documents are binarized and well binarized results are obtained