Determination of an orientation parameter of an elongate object with a scan beam apparatus

摘要

An elongate object optically determines at least one of its orientation parameters relative to a plane surface. A probe radiation beam is directed from the object at various angles sigma to various locations on the plane, where the angle sigma is a periodic function of time. Two angularly-selective radiation detectors oriented at fixed angles tau₁ and tau₂ sense scattered portions of the beam from two locations at two corresponding times. The orientation parameter is computed from a time difference Deltat=t₂-t₁ between the two times.