Infrared Sensing - Optical flow sensors: An introduction

摘要

The optical flow sensor (OFS) and its predecessor, the long-baseline optical anemometer (LOA) use optical scintillation as their detection method, The LOA is a sensor that uses the same technology as the OFS but measures along much longer path lengths, 100m to 10 km, Scintillation is a general term, which describes changes in the apparent position or brightness of an object when viewed through the atmosphere, A common example of this phenomenon is the twinkling of starlight. These fluctuations occur as light passes through pockets of air with differing temperature and density, causing the refraction and scattering of the light through the non-homogenous air, By detecting the speed of movement of this scintillation, the OFS can measure air velocity in a stack or duct You can see the mechanism of this scintillation or optical turbulence in the scintillation diagram.