关键词: 车牌, 倾斜校正, Radon变换

Abstract: Tilt vehicle license plate have a bad effect on its character segmentation and recognition.In this paper，a novel approach for number plate tilt correction based on Radon transform is presented.Radon transform in the range of [-20°，20°] is implemented on the number plate images.Then the accumulative total of absolute value of difference of the results is calculated，respectively.The angle of the Radon transform corresponding to the maximal accumulative total is confirmed as a skew angle of the number plate.Bilinear interpolation rotation correction is performed to the plate that is tilt to the horizontal line，and bilinear interpolation offset correction is made to the plate that is tilt to the vertical line.Experimental results show that the method can be implemented easily and offers robustness when dealing with dirty license plates and license plates in variant lighting conditions.

Key words: vehicle license plate, tilt correction, Radon transform