关键词: 限速标志, 先验特征, AdaBoost算法, Hough变换

Abstract: How to detect traffic sign from real scene is a key step in traffic recognition system.According to the color and shape characteristics of Chinese speed limit traffic signs，this paper proposes a new kind of filtering approach that is used to obtain an elliptical model where red pixels cluster in Lab color space.Then the elliptical model is used to extract area of red pixels and gain the binary image of traffic sign.After that，the improved Hough transform is used to detect elliptical region of binary image of traffic sign.The result comes true an intelligent speed limit sign detection method that combines the priori characteristics of the traffic sign and machine learning algorithm.

Key words: speed limit sign, priori characteristics, AdaBoost, Hough transform