Enhancement of document images using multiresolution and fuzzy logic techniques

This letter presents a method for enhancing document images based on the multiresolution decomposition and fuzzy logic approach. The document image to be enhanced is obtained from a scanner and is a blurred binary image that is corrupted by additive noise. This type of image occurs in many situations when documents such as checks and credit card receipts become noisy and low-contrast images after scanning, thereby reducing its quality. Our task is to improve the readability of such images by reducing the noise and increasing the sharpness of the text. This is achieved using the multiresolution decomposition, fuzzy logic and contrast enhancement operator. The improvement is shown using simulation examples and compared with other enhancement techniques.