An Improved Method for Vietnam License Plate ...

The License Plate Location (LPL) is the key step in the Automatic License Plate Recognition (ALPR). In this paper we proposed a new LPL algorithm for Vietnam license plates (LP), which included preprocessing, morphology operation and image subtraction on grayscale image, image binarization based on threshold, edge detection using Canny operator, morphology operation on binary image, finding the LP angle & rotating LP based Radon transform and bilinear interpolation, and then cutting exactly LP region based on measuring properties of Vietnam LP regions. Our proposed approach is more effective than some earlier existing method and is satisfied with Vietnam LP. We implemented 500 images taken from different light conditions (night and day), LP angles, illumination, sizes and types of LP, colors, and reflected light. The average rate of accuracy is 97.27% for all of types and colors of Vietnam LP.