Abstract: In order to obtain non-dim and stable images,this paper proposed an automatic exposure algorithm of camera．Firstly,traffic signs are detected in the first frames image,and Region of Interest(RoI) is determined in 9fixed partitions according to the results of traffic sign detection．Then the exposure situation is accurately judged by the histogram of V component in HSV color space,and weight matrix is selected according to the location of the interested region and exposure situation．Lastly,the exposure time of next frame image is got using gray value method,and the camera's automatic exposure is completed．The experimental results show that this method can quickly and effectively complete automatic exposure,and is adaptable for the backlight and backlit cases．

Key words: Auto exposure,Intelligent vehicle,Luminance image,Exposure time,Histogram