Abstract: We describe a real time vision system for electronic billboards that can detect and count number of people standing in front of the billboards, determine how long they have been looking at the advertisements currently shown on the billboards, and try to obtain demographics information about the audience automatically to determine when and which advertisements might be shown on the electronic billboard to reach targeted audience. As the location of billboard, such as coffee shops, stores are very crowded areas where people either are waiting or moving together, individual person cannot be isolated but are partially or total occluded by other people. We combined silhouette and motion based people detection, with fast infrared illumination based pupil detection to detect people and determine whether they are looking at the billboards or not. Experimental results demonstrate robustness and real-time performance of the algorithm.