Non-Contact Velocity Measurement System Using Spatial Filter Constructed by Optical-Electrical Circuit

A decting system of the velocity of moving pattern is constructed by using the spatial filter with-out mechanical parts. The filter is composed of optical fibers associated with phototransistors and electrical analogue gate circuits. The movement of the window is carried out by supplying the pulse of the rectangular form to the analogue gate circuits. The accuracy of the measurement with this method is discussed theoretically. It is shown that the present method is not so inferior to the mechanical one in accuracy of the measurement (within 3%). The observed velocity is linearly changed with increasing the velocity of the moving patterns in the range of 0.01m/sec&acd