Subpixelic Measurement of Large 1D Displacements: Principle, Processing Algorithms, Performances and Software

Sensors

Valérian Guelpa¹  Guillaume J. Laurent¹  Patrick Sandoz³  July Galeano Zea² 

[1] Automation and Micro-Mechatronics Systems Department, FEMTO-ST Institute, UMR CNRS 6174, ENSMM, Université de Franche-Comté, 25000 Besançon, France; E-Mails:;Instituto Tecnológico Metropolitano, Grupo de Materiales Avanzados y Energía, 05001 Medellin, Colombia; E-Mail:;Applied Mechanics Department, FEMTO-ST Institute, UMR CNRS 6174, ENSMM, Université de Franche-Comté, 25000 Besançon, France; E-Mail:

关键词: displacement sensing;    subpixelic measurement;    nanometric precision;    extended range-to-resolution ratio;    real-time image processing;    twin-grid pattern;    direct phase computation;   

DOI  :  10.3390/s140305056

来源: mdpi

【 摘 要 】

This paper presents a visual measurement method able to sense 1D rigid body displacements with very high resolutions, large ranges and high processing rates. Sub-pixelic resolution is obtained thanks to a structured pattern placed on the target. The pattern is made of twin periodic grids with slightly different periods. The periodic frames are suited for Fourier-like phase calculations—leading to high resolution—while the period difference allows the removal of phase ambiguity and thus a high range-to-resolution ratio. The paper presents the measurement principle as well as the processing algorithms (source files are provided as supplementary materials). The theoretical and experimental performances are also discussed. The processing time is around 3 μs for a line of 780 pixels, which means that the measurement rate is mostly limited by the image acquisition frame rate. A 3-σ repeatability of 5 nm is experimentally demonstrated which has to be compared with the 168 μm measurement range.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.