Simultaneous acquisition of 3D shape and deformation by combination of interferometric and correlation-based laser speckle metrology

Biomed Opt Express. 2015 Nov 13;6(12):4825-40. doi: 10.1364/BOE.6.004825. eCollection 2015 Dec 1.

Abstract

A metrology system combining three laser speckle measurement techniques for simultaneous determination of 3D shape and micro- and macroscopic deformations is presented. While microscopic deformations are determined by a combination of Digital Holographic Interferometry (DHI) and Digital Speckle Photography (DSP), macroscopic 3D shape, position and deformation are retrieved by photogrammetry based on digital image correlation of a projected laser speckle pattern. The photogrammetrically obtained data extend the measurement range of the DHI-DSP system and also increase the accuracy of the calculation of the sensitivity vector. Furthermore, a precise assignment of microscopic displacements to the object's macroscopic shape for enhanced visualization is achieved. The approach allows for fast measurements with a simple setup. Key parameters of the system are optimized, and its precision and measurement range are demonstrated. As application examples, the deformation of a mandible model and the shrinkage of dental impression material are measured.

Keywords: (030.6140) Speckle; (100.0100) Image processing; (120.0120) Instrumentation, measurement, and metrology; (120.2880) Holographic interferometry; (120.4290) Nondestructive testing; (150.0150) Machine vision.