Volume 33, Issue 4 (July 1988)
A Computer-Aided Seal Discriminating System
A computer-aided system for seal discriminating is developed. The system uses the state-of-the-art technology of digital image processing. The conventional methods such as diagonal match and full match are computerized. The advantage of the computerized method is that it is nondestructive and fast. With the use of proper optical lens, it offers good accuracy. The computerized method can compare the geometry and the intensity variation, while the conventional method is limited to the geometry match. The intensity variation carries information about the seal surface smoothness, the ink concentration, the seal material, the paper material, the paper support, and so forth. The seal surface smoothness is the kind of characteristic which cannot be reproduced easily. It is believed that the surface smoothness is the key to breaking the advanced forging techniques. The system was made and is used at the Central Investigation Bureau of Taipei, Taiwan.