Vehicle license plate slant correction based on mathematical morphology and Radon transformation

摘要

Slant vehicle license plate had the bad effect on its character segmentation and recognition. In this paper, a new method to remedy the effect based on mathematical morphology and Radon transformation was presented. According to the Radon transformation, the corresponding correction methods are presented for three inclined ways. Firstly, the edge of the plate picture is detected by the related operation of mathematical morphology. Then, lossless rotation correction is performed to the tilt plate to the horizontal direction, and bilinear interpolation offset correction is made to the plate that is tilt to the vertical direction. Experimental results show that the method can be implemented easily and offers robustness when dealing with dirty plates and license plates in variant lighting conditions.