HEURISTICS FOR LICENSE PLATE DETECTION AND EXTRACTION

License Plate Detection from images requires the segmentation of the license plate (LP) region from the larger image acquired by the camera. While there may be several LP candidate areas, the detection of the LP area (LPA) requires various diverse methods of image processing to be applied. After detection of a candidate LPA we extract the possible alphanumeric information. We further process the LPA information using heuristics to reject those candidates which may contain alphanumeric like region but which may not be LP information. In this paper we present several heuristics that successfully allow the detection and extraction of alphanumeric regions from correctly identified LPA. Subsequently the extracted alphanumeric regions are recognized by Optical Character Recognition (OCR). Experiments on a number of images on Indian as well as international license plates acquired from the internet and some of our own images are shown here. We find that an accuracy of 88% is obtained from the images in the dataset. The open source software OpenCV configured with Code Blocks IDE (http://sourceforge.net/projects/opencvlibrary/) was used for the experimentation.