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Micro/Nano-scale Strain Distribution Measurement from Sampling Moiré Fringes
Published on: May 23, 2017
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Subpixel sampling moiré method for in-plane displacement measurement considering the symmetric errors induced by
Applied Optics
|March 10, 2021
Summary
A novel subpixel Sampling Moiré Method (SMM) enhances deformation measurement accuracy. This vision-based technique improves precision by using subpixel interpolation and an average filter for in-plane deformation analysis.
Area of Science:
- Optical Metrology
- Materials Science
- Mechanical Engineering
Background:
- The Sampling Moiré Method (SMM) is a vision-based technique for accurate deformation measurement.
- Traditional SMM achieves minimal error when the sampling pitch is an integer closest to the grating pitch.
Purpose of the Study:
- To develop an improved SMM with enhanced accuracy for in-plane deformation measurement.
- To introduce a subpixel SMM that overcomes limitations of traditional integer sampling pitches.
Main Methods:
- A subpixel interpolation operation is applied before downsampling in the SMM process.
- The sampling pitch is selected as a non-integer value closest to the grating pitch in the subpixel-resolved image.
- An average filter is employed to mitigate symmetric errors introduced by interpolation.
Main Results:
- The subpixel SMM significantly enlarges the moiré fringe period, leading to increased measurement accuracy.
- Computer simulations validated the accuracy of the proposed subpixel SMM.
- Experimental results from a tensile test showed strong agreement between subpixel SMM and fiber Bragg grating measurements.
Conclusions:
- The proposed subpixel SMM offers a novel approach for high-accuracy in-plane deformation measurement.
- This method demonstrates superior performance compared to traditional SMM techniques.
- The subpixel SMM is a viable tool for precise deformation analysis in various engineering applications.
