Hey everyone, I've been trying to tackle the issue of autonomous landing for a little while now, specifically restrained to optical flow techniques. I have hit a roadblock and wanted to see if anyone on here could shed some advice on the issue.

Essentially what is happening is I have a downward looking vision chip that can successfully put a Coaxial helicopter into a hover using a minimization of OF. I want that chip to now track a moving surface underneath it, particularly a landing platform. The problem lies in that the helicopter has no way of knowing the linear velocity of the thing it is tracking. Because the OF is only calculating a height/speed ratio, there is no way to know exactly how far the surface it is tracking has displaced in the X and Y direction. I am trying to avoid using other sensors that would give me height over ground because my objective is to operate using only vision chips. Therefore, unless I constrain the speed of the landing platform and keep the height of my UAV at a very fixed height to match the linear velocity of the platform, does anyone have any suggestions on how to remedy this issue?

For reference, I am programming via an Arduino board and I am using a Centeye 16X16 vision chip.