Optical Flow Techniques for Wind-Velocity Sensing on a Small Unmanned Aircraft System

摘要

Optical correlation techniques for wind velocity sensing have the potential to improve vertical wind velocity measurements from fixed wing sUAS an order of magnitude, from tens of cm/s to one cm/s. This is due to the insensitivity of optical correlation to the relatively large forward velocity component of the oncoming flow. This reduces the precision requirements of the measurement. Using optical flow techniques on sUAS does offer unique challenges, however. The structures in the fllow deform over time, making it impossible to find exact matches of common shapes between image pairs. This deformation must be small enough that the correlation is still able to match the rough shape of a structure from one image to the next. A second challenge is the dilation of images, as structures will appear to grow in size from one image to the next. Accounting for this is easily done using basic geometry.