An image authentication method for paper checks

In this paper, we propose an image authentication method based on digital image watermarking approach for paper checks. In the process of watermark embedding, a binary watermark image is added into the blue color component of a white color image. Paper check template is overlaid on the result, and printed out on a piece of paper. In the watermark extraction process, a paper check is first scanned back to obtain an electronic copy. A technique of image registration based on affine transformation is then applied to reduce geometric distortions from the printing and scanning processes, followed by a thresholding step to estimate the embedded bit in each watermarked component. The performance of the proposed method was investigated using different scanning resolutions and printing quality modes. Its extraction performance from the paper checks with written texts and folded marks was also investigated. The promising results demonstrate the effectiveness of the proposed method.