A Vehicle License Plate Recognition System Based on Spatial/Frequency Domain Filtering and Neural Networks

In this paper, we develop an intelligent application based neural networks and image processing to recognize license plate for car management. Through the license recognition, the car number composed of English alphabets and digitals is readable for computers. Recognition of license is processed in two stages including feature extraction and recognition. The feature extraction contains the image locating, segmentation of the region of interest (ROT). Then the extracted ROIs are fed to a trained neural network for recognition. The neural network is a three-layer feed-forward neural network. Test images are produced from real parking lots. There are 500 images of car plates with tile, zooming and various lighting conditions, for verification. The experiment results show that the ratio of successful locating of license plate is around 96.8%, and the ratio of successful segmentation is 91.1%. The overall successful recognition ratio is 87.5%. Therefore, the experimental result shows that the proposed method works effectively, and simultaneously to improve the accuracy for the recognition. This system improves the performance of automatic license plate recognition for future ITS applications.