scholarly journals Robust sub-micrometer displacement measurement using dual wavelength speckle correlation

2015 ◽  
Vol 23 (11) ◽  
pp. 14960 ◽  
Author(s):  
Mahsa Farsad ◽  
Chris Evans ◽  
Faramarz Farahi
Keyword(s):  
Displacement Measurement ◽  
Dual Wavelength ◽  
Speckle Correlation

scholarly journals Integrated, Speckle-Based Displacement Measurement for Lateral Scanning White Light Interferometry

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2486
Author(s):  
Gert Behrends ◽  
Dirk Stöbener ◽  
Andreas Fischer
Keyword(s):  
White Light ◽  
Lateral Displacement ◽  
Displacement Measurement ◽  
Accurate Information ◽  
White Light Interferometry ◽  
Fully Integrated ◽  
Speckle Correlation ◽  
Dsc Measurements ◽  
Scanning White Light Interferometry ◽  
The Impact

Lateral scanning white light interferometry (LSWLI) is a promising technique for high-resolution topography measurements on moving surfaces. To achieve resolutions typically associated with white light interferometry, accurate information on the lateral displacement of the measured surface is essential. Since the uncertainty requirement for a respective displacement measurement is currently not known, Monte Carlo simulations of LSWLI measurements are carried out at first to assess the impact of the displacement uncertainty on the topography measurement. The simulation shows that the uncertainty of the displacement measurement has a larger influence on the total height uncertainty than the uncertainty of the displacing motion itself. Secondly, a sufficiently precise displacement measurement by means of digital speckle correlation (DSC) is proposed that is fully integrated into the field of view of the interferometer. In contrast to externally applied displacement measurement systems, the integrated combination of DSC with LSWLI needs no synchronization and calibration, and it is applicable for translatory as well as rotatory scans. To demonstrate the findings, an LSWLI setup with integrated DSC measurements is realized and tested on a rotating cylindrical object with a surface made of a linear encoder strip.

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