A Novel Approach for Vehicle License Plate Tilt Correction

Tilt vehicle license plate has a bad effect on its character segmentation and recognition. In this paper, tilt models of a plate are analyzed and a novel approach for number plate tilt correction is presented. Horizontal or vertical incline angle is obtained by combining horizontal or vertical color edge of a plate with its rotation projection. 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 number plates and license plates in variant lighting conditions.