Historical document enhancement using Shearlet Transform and mathematical morphological operations

Abstract

Document image binarization is a process of converting the document image into binary image containing text as foreground and plain white as background or vice versa. Characters from the document image should be extracted from the binaried image, in order to recognize them. So performance of the character recognition system completely depends on the binarization quality. In this paper, an efficient hybrid binarization method is proposed to binarize the degraded document image. The proposed method is based on: Adaptive Histogram Equalization (AHE), Shearlet Transform (ST) and simple morphological reconstruction techniques and proved better in enhancing degraded documents images. The proposed technique is efficient to tolerate the high inter and intra intensity variation in the degraded document image.