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High-resolution, High-speed, Three-dimensional Video Imaging with Digital Fringe Projection Techniques
Published on: December 3, 2013
Complete fringe order determination in scanning white-light interferometry using a Fourier-based technique
Young-Sik Ghim1, Angela Davies
1Center for Space Optics, Korea Research Institute of Standards and Science, Daejeon, South Korea.
Applied Optics
|April 27, 2012
Summary
This study introduces a modified white-light interferometry technique to eliminate ghost steps caused by surface curvature. The improved method enhances measurement accuracy for three-dimensional surface profiling.
Area of Science:
- Metrology
- Optical Engineering
- Surface Science
Background:
- White-light interferometry (WLI) is a key technique for 3D surface profiling, offering high vertical resolution without 2π-ambiguity.
- WLI combines coherence and phase information for precise measurements, but struggles with highly curved surfaces.
- Inconsistencies in curved surfaces lead to measurement errors known as 'ghost steps'.
Purpose of the Study:
- To develop a modified WLI technique to overcome limitations with curved surfaces.
- To eliminate ghost steps and enhance the accuracy of 3D surface profile measurements.
- To validate the proposed method through experimental measurements.
Main Methods:
- Modification of the standard white-light interferometry system.
- Integration of advanced algorithms to reconcile phase and coherence data.
- Experimental verification using various test samples with different surface curvatures.
Main Results:
- Successfully eliminated ghost steps in measurements of spherical and tilted surfaces.
- Demonstrated significant improvement in the accuracy of 3D surface profile measurements.
- Validated the robustness and effectiveness of the modified WLI technique.
Conclusions:
- The proposed modified white-light interferometry effectively eliminates ghost steps.
- This advancement significantly improves measurement accuracy for complex 3D surfaces.
- The technique offers a more reliable solution for high-precision surface metrology.
