Abstract: A grad intensity method is put forward to process edges’ intensity of an image, this measure mostly uses simple grad transform to potentate the image edges, at the same time, a dilation method of mathematical morphology is applied to achieve rapid orientation of the license plates. In the process of characters segmentation, we first proposed least area circumrotation means in order to ascertain the best rotation angle of the license plate, then we adopted the way of perpendicularity projection to segment the characters of the license plate.

Key words: pattern recognition, license plate recognition, edge enhancement, dilatation, bounding box, subdivision