CROSS INFLUENCE OF COORDINATE AND SLOPE RELATED FRINGES DURING SHEAROGRAPHIC PROFILING

In this paper, an optical technique based on speckle-shearing interfer ometry is employed for the measurement of surface coordinates and slop es. By the double exposure technique and shifting the light source in a prescribed manner between the exposures, carrier and slope related f ringes are generated. The surface coordinates and slopes are determine d from the carrier and slope fringes respectively. Theoretical derivat ion shows that the resulting fringe pattern is a mixture of both carri er and slope fringes. The mutual influence of each parameter (carrier and slope) on the resulting fringe pattern ir studied. The results dem onstrate that the slope parameter has a dominating influence on the re sulting fringe pattern. Experimental results conducted on objects of k nown shapes compare favourably with the computed fringe patterns. Copy right (C) 1996 Elsevier Science Ltd.