Fiber-optic grid interferogram shape sensing system

Based on the three-fiber-optic grid interferogram technique, a shape sensing approach has been proposed and demonstrated in this paper. The square and hexagon grid interferometric fringe pattern formed by the fiber-optic interferometric grid generator has been designed and performed. The designing and realizing methods of the fiber-optic interferometric grid pattern by using three PM fibers are discussed. Theoretically, the three-fiber coherence optical field intensity distribution has been deduced. By using the 2-D Fourier transform methodology, the object surface can be reconstructed from the modulated fiber-optic grid interferogram pattern. The multiphase data fusion method has been used in our experiments, which greatly improved the accuracy of the 3-D shape measuring results.