Abstract:

Accurate license plate location is the basis of license plate recognition. The existing approaches of license plate location are easy to be affected by background and illumination, which leads to a low accuracy of license plate location. To solve this issue, we propose a novel license plate location method based on morphological gradient reconstruction. Firstly, the candidate license plate regions are detected through the color information of a license plate. Secondly, vector gradient operator is used to obtain the gradient image of the candidate areas, and then morphological gradient reconstruction operation is used to extract the image structures with the characteristic of license plate shape and  suppress the image structures without the characteristic of license plate shape. Finally, the rectangle areas are extracted according to the prior information of the fixed widthlength ratio of a license plate. Experimental results show that the proposed method can accurately locate the license plate in complex environment in real time with high robustness.

Key words: vector gradient;morphological gradient reconstruction;license plate location;robustness