Contouring of moving technical surfaces via speckle-interferometry

Growing demands on quality inspection in industrial manufacturing require new methods for fast and non-destructive surface inspection. For surface contouring the speckle interferometry provides the two-wavelength technique. So far both the enormous susceptibility of interferometric measurements to any movements of the measurement object and the long calculation time for evaluating the interferograms hardly permitted any industrial applications. A new kind of setup is presented which is capable of simultaneously recording all data necessary for interferometric contour measurement using a system of two spatially separated cameras. Thus measurements of moving objects become possible. A data flow and hardware based evaluation of the interferograms with FPGAs (Field Programmable Gate Arrays) enables a high frame rate whereby the device becomes attractive for industrial applications.