Hi, I am a final year student whos doing engineering degree. My final year project involves tracking the speed of a swimmer inside a pool. The current problem is that i dont have a good way of monitoring the swimmer's speed, which needs to be quite accurate(centimeters). Due to different stroke patterns and unregular shape of human body, it is very hard to find a way of getting the swimmer's speed during motion. I've been thinking about infra-red sensors, ultra sonic sensors and also other methods. Is there any way of using sensors wisely and place them the right way so that i can accurately get the motion of the C.O.M. of the swimmer OR the mid-point of the body length? Very appreciated for any suggestions or ideas. Regards, Kent Zhou.