Abstract: The pressed character is a reflectorized character on the difference of reflectance. The image quality of the protuberant character is lower than the generally character on the chromatic difference of background and foreground. So, the general testing method based on the binary-scale character can’t adapt for the pressed character. To solve this problem, a new method of direct gray-scale feature extraction based on the circular projection algorithm and the vector sum for testing the quality of the pressed character is presented. The new method keeps integrity feature of the protuberant character information dramatically, and can overcome the main shortages of the traditional method on binary-scale image, such as to depend on a binarization algorithm extremely, lower performance of anti-jamming. A limited set of the tag pressed protuberant characters is extracted feature and tested by the new method. The results show that the proposed method adapts to the variant gray-scale, location and orientation of the character, and can yield an excellent performance on the pressed character quality using to adjust the testing threshold value. It has highly worth applying to correlated fields.

Key words: Circular projection, Pressed protuberant character, Quality testing, Vector sum