Velocity Measurement for Moving Surfaces by Using Spatial Filtering Technique Based on Array Detectors

Spatial filtering velocimetry is an established measurement technique for process control e. g. measuring speed of moving surfaces. The technique uses optical gratings for filtering the velocity information. Usually optical transmission gratings as films or micro-lenticular arrays are used for generating the spatial filter. The article describes the spatial filtering technique by using structured detectors (CCD or CMOS-array), which reduces the optical setup significantly. The grating of the spatial filter is realized by weighting lines of pixels, possible for array detectors in different directions. After describing the technique and the realized system some measurement results are shown.