I. Introduction
Automatic traffic sign recognition (TSR) has important application in intelligent transportation systems. It is a complex pattern recognition problem, requiring accurate recognition in real-time, because traffic signs are generally detected from live video during fast movement of vehicles. Both traffic sign detection and recognition encounters multitude of difficulties and have attracted high attention of research. Traffic sign recognition is challenging due to the fast changing environment and illumination, cluttered background, low resolution, shape distortion resulted from changing camera angles.