A Vehicle License Plate Detection Method for Intelligent Transportation System Applications

Detecting license plates is crucial and inevitable in the vehicle license plate recognition system. In this article, a Hue-Saturation-Intensity (HSI) color model is adopted to select automatically statistical threshold value for detecting candidate regions. The focus of this article is on the implementation of a new method to detect candidate regions when vehicle bodies and license plates (LP) have similar color. The proposed method is able to deal with candidate regions under independent orientation and scale of the plate. For the decomposing candidate regions, predetermined LP alphanumeric characters are used by position histogram to verify and detect vehicle LP regions. Various LP images were used with a variety of conditions to test the proposed method and results proved its effectiveness.