Seal Image Registration Based on Shape and Layout Characteristics

A novel seal registration method for Chinese seal verification is proposed in this paper using shape and layout characteristics. Seal registration is the process that aligns the sample seal imprint with the model seal imprint geometrically. The proposed method firstly classifies the seal imprints into one of the three shapes (rectangle, ellipse and circle) which are most common in China. Rotation angle of rectangular or elliptical seal imprint is estimated simultaneously with the shape classification procedure. Secondly, layout analysis and character distribution characteristics are used to estimate the rotation angle if the input is considered as a circular seal imprint. Finally, the input seal imprint image is rotated to horizontal direction and the best alignment between the sample seal image and the model seal image is made by translation transform. Experiments show that this proposed method performs very well in seal image registration. And the speed is much faster than the correlation-like methods proposed by other researchers.