Method of Contactless Measurement of Large Object Deformations Based on Structured Illumination

摘要

The possibility of determining deformations of large-sized objects by structured illumination is considered. The method is based on projection of sinusoidal fringe patterns on the surface of the object under study. Using the step-by-step phase shift allows one to distinguish information about the phase distribution reflecting the surface relief. Comparison of phase distributions before and after the action on the object makes it possible to establish the deformation field. A new method of finding phase differences is presented; it considerably reduces demands to phase ambiguity elimination algorithms. An experimental facility for the determination of ultimate sensitivity of the method when investigating deformations of a clamped cantilever beam is developed. It is shown that the sensitivity of the method is less than 10 mu m at the free end of the beam.