An automatic camera system for distant lecturing system

High-speed communication networks and multimedia processing techniques enable us to attend a distant lecture. When the lecturing scenes are taken, a camera-person controls the camera in order to capture suitable scenes; otherwise, the camera is set to capture the same position at all times. Since the scene sent from a fixed camera is unable to give us the feeling of being at the live lecture, we would like to pan or tilt the camera to follow the teacher´s action. Therefore, a mechanism to control a camera automatically is necessary. We describe experiments on an automatic camera system for taking lecture scenes. Computer vision techniques are used to implement the system. We have categorized the teacher´s actions into three states. The first is a state explaining without a blackboard; the second is one writing on a blackboard or explaining with it; the last is one moving in front of a blackboard. We assumed that the teacher is in one of the three states in a lecturing scene, and have examined how to control a camera in each state. We have implemented two prototypes: one is a prototype following a teacher; the other is a prototype estimating the teacher´s posture