machine vision. I've envisioned a system similar to what hawks might use. A video camera with telescope in the cockpit is connected to a computer and to a very sensitive vario. The idea is for the camera to spot bugs, leaves, etc. in the air and then determine their vertical motion and approximate rate. Since we are a moving platform we must subtract out the motion of the sailplane in the vertical to obtain a true picture of what the remote objects are doing. If you've ever looked at distant bugs with a powerful telescope you know the problems that would occur with this scheme. But it could be done.