A novel algorithm for character segmentation of degraded license plate based on prior knowledge

This work proposes a novel algorithm for character segmentation of degraded license plate based on prior knowledge. Firstly, this algorithm performs preprocessing on the license plate, such as size normalization, uneven illumination correction, contrast enhancement, incline correction and edge enhancement; then, locates the character segments according to the vertical projection and merges the character segments that belong to the same character or splits the wider character segment according to the prior knowledge; finally, segments the characters according to the number and the width of the character segments. This algorithm is more efficiency under the condition that the license plate images are degraded, such as declining, faded, distorted, fogged, etc, quality degradation license plate.