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E. Csencsics, T. Wolf, G. Schitter:
"Speckle Simulation Tool for the Design of Laser-based Displacement Sensors";
Talk: SPIE Optical Metrology Conference 2021, Munich, Germany; 06-21-2021 - 06-25-2021; in: "SPIE Optical Measurement Systems for Industrial Inspection XII", SPIE, 11782 (2021), 117820 pages.

This paper presents the development of a versatile, accurate and efficient speckle simulation tool for the design of laser-based displacement sensors, capable of handling objective as well as subjective speckles. The simulation tool integrates the statistical nature of speckles with the deterministic properties of ray-tracing simulations, providing a reliable estimation of the performance of laser and/or speckle-based sensors in the design phase, even for more complex optical assemblies. It enables the calculation of several simulation outputs in order to determine the best performing system configuration for a given requirement and measurement principle. To validate the simulation results, they are compared against the experimental data of four designed laser-speckle based sensor setups for measuring in- and out-of-plane displacement of a target as well as against analytical relations for describing speckle pattern translation for simple geometries. With resulting simulation errors of less than 2 μm rms for in-plane (output: correlation peak shift) and 2.6 μm for out-of-plane displacements (output: center of gravity shift) for an integrated laser sensor geometry, the good accuracy of the speckle simulation tool is demonstrated.

Laser speckles, Speckle simulation, Triangulation sensor, Displacement measurement, Surface tracking, In-process measurement, Design tool

http://dx.doi.org/10.1117/12.2592596

https://publik.tuwien.ac.at/files/publik_296573.pdf