License Plate Recognition Method for Passing Vehicles Outdoors

Abstract

This paper presents novel methods of recognizing vehicle license plates robustly. To acquire fine images of quickly passing vehicles under a wide range of illumination conditions, we developed a sensing system having superb characteristics. We expanded the dynamic range and eliminated the blurring of images of fast moving vehicles by synthesizing a pair of synchronized images with different intensities. Furthermore, to extend the flexibility of the positioning of the TV camera, we propose a recognition algorithm which can be applied to inclined plates. The performance of the integrated system was investigated on real images of highly inclined plates of vehicles captured under various illumination conditions. The recognition rate of 97% shows that the developed system is effective for license plate recognition.