Marginal noise removal for scanned document images by projection profile based method

Significant documents or old scarce books have been saved in digital forms by scanning. However, some noises may occur in a scanned image such as marginal noises. The marginal noises usually appear as dark regions around the margin of the scanned documents. In this paper, we propose a method for removing marginal noise by analyzing image histogram or projection profile of the document image. The method consists of the following main steps: Creating image profile; Smoothing the profile by using moving average technique; Dividing the projection profile of the document image into three regions: left, middle, and right; Detecting marginal noises by finding the highest peaks of the projection profile in the corresponding regions; Removing the detected marginal noises by replacing the regions of marginal noises with white pixels. We had performed experiments on 50 input digital document images. The proposed method can detect and remove the marginal noises with a high average accuracy rate of 93.8% which is significantly higher than that of the tradition method, 77.5%, using the original projection profile.