Color Prior Knowledge-Based License Plate Location Algorithm

Vehicle license plate location is the key of the vehicle plate recognition system. This paper proposes a new method that sufficiently utilizes the color feature such as fixed color collocation, color centers and distribution in the plate region. In this method, firstly, the input image is convolved with 1-D Gaussian filter, and the regions which have the structure and texture are similar to the license plate are extracted. Then improved fuzzy C-means (FCM) is used to color clustering in the RGB color space. Finally, according to the clustering center and color distribution, the plate region was chosen from the candidate regions. The experimental results of more than 250 images collected show that the method is more accurate and robust to environment variation, and the rate of location is above 98%.