PatR
Premium Pilot
The principle is quite feasible, and one used extensively with military grade UAV systems. It is also extremely expensive to incorporate and requires a massive level of computational power. A system pretty much requires a computer program, or separate computer, dedicated to target lock technologies. The camera/gimbal system also needs to be far more sophisticated, inclusive of an image adaptive smoothing program, than what small multirotors are capable of providing at a price point the vast majority can possibly afford. At super zoom levels the gimbal is not effective for stabilizing the image, it's done through image stabilization programs as the imagery is received at the ground station.