Modified Adaptive Contrast Based Degraded Document Image Binarization Technique

Segmentation of text from badly degraded document images is a very challenging task due to the high inter/intravariation between the document background and the fore- ground text of different document images. This paper, propose a novel document image binarization technique that addresses these issues by using modified adaptive image contrast. The modified adaptive image contrast is a combination of the local image contrast and the local image gradient that is tolerant to text and background variation caused by different types of document degradations. In the proposed technique, a modified adaptive contrast map is first constructed for an input degraded document image. The contrast map is then binarized and combined with sobel edge map to identify the text edge pixels. The document text is further segmented by a threshold that is estimated based on the intensities of detected text edge pixels with the mean and standard deviation. The proposed method is simple, robust, and involves minimum parameter tuning.