Nowadays seals play an important role in China. With the development of social economy, the traditional method of
manual check seal identification can't meet the need s of banking transactions badly.
This paper focus on pre-processing and registration algorithm for check seal verification using theory of image
processing and pattern recognition. First of all, analyze the complex characteristics of check seals. To eliminate the
difference of producing conditions and the disturbance caused by background and writing in check image, many methods
are used in the pre-processing of check seal verification, such as color components transformation, linearity transform to
gray-scale image, medium value filter, Otsu, close calculations and labeling algorithm of mathematical morphology.
After the processes above, the good binary seal image can be obtained.
On the basis of traditional registration algorithm, a double-level registration method including rough and precise
registration method is proposed. The deflection angle of precise registration method can be precise to 0.1°.
This paper introduces the concepts of difference inside and difference outside and use the percent of difference inside
and difference outside to judge whether the seal is real or fake. The experimental results of a mass of check seals are
satisfied. It shows that the methods and algorithmic presented have good robustness to noise sealing conditions and
satisfactory tolerance of difference within class.