SVM-based Seal Imprint Verification Using Edge Difference

In Asian countries, seals are widely used for authenticating the identity of a person or organization. Therefore, the ability to efficiently verify whether a seal is either genuine or forged is important. We propose an effective method of verification based on Hough transformation to approximate the imprint borders and the four vertexes, and use geometric transformation to align the perspective of the detected imprint image with the genuine imprint. After the edge-difference images between the original image and the detected image are created, distance transformation and connected-component labeling are applied. Finally, the number of edges in the connected component and the distance to the closest point in the edge of original image are used to calculate the input vector for the SVM (support vector machine). The imprint is then determined to be either genuine or forged. The experimental results show the effectiveness of the proposed verification approach.