A robust seal imprint verification method with rotation invariance

This paper presents a robust seal imprint verification method with rotation invariance. The rotation invariant feature is represented by the absolute value of Fourier coefficients of log-polar image of seal imprint on circles with different radii. Firstly, the feature vector of a seal imprint is defined by the above absolute value of Fourier coefficients of the log-polar image. Secondly, the feature vector is expanded into Karhunen-Loeve (K-L) expansion. Thirdly, seal imprint is verified using the distance between vectors defined by coefficients in K-L expansion corresponding to true and given seal imprints. Finally, seal imprint verification experiments are given to show the effectiveness of the proposed method.