APPLICATION OF IMPROVED SPECKLE CONTOURING TECHNIQUE TO SURFACE-ROUGHNESS MEASUREMENTS

One of the well known drawbacks in Electronic Speckle Pattern Interfer ometry (ESPI) is the poor fringe density due to electronic and speckle noise and decreasing fringe visibility with increasing speckle decorr elation. As recently reported we suggested improving the fringe densit y and enlarging the measurement range by the incremental addition of p hase images. The technique has already been successfully applied to in -plane and out-of-plane displacement field measurements of carbon-fibr e reinforced. composites. This paper demonstrates how the technique ca n be used to improve the sensitivity and to extend the measurement ran ge for speckle contouring applications. The angular correlation of the speckle phase images is used to get the desired 30 information of the investigated object surface. It is demonstrated how the angular speck le contouring techinque can easily be automated with respect, for exam ple, to possible industrial applications. Roughness measurements are c arried out on milled Rugo test surfaces. All measurements are performe d without the usual vibration isolation, and of course, without the tr eatment of the surface with fine, white powder for contrast enhancemen t, which would falsify the results. Copyright (C) 1996 Elsevier Scienc e Ltd.