A Novel Surface Recovery Algorithm for Dual Wavelength White LED in Vertical Scanning Interferometry (VSI)
Linlin Zhu1, Yuchu Dong1, Zexiao Li1
1State Key Laboratory of Precision Measuring Technology & Instruments, Centre of MicroNano Manufacturing Technology, Tianjin University, Tianjin 300072, China.
Sensors (Basel, Switzerland)
|September 16, 2020
Summary
Dual-wavelength white light interferometry using LEDs creates signal discontinuities, impacting 3D reconstruction accuracy. A new Hilbert phase envelope algorithm overcomes these issues for reliable surface recovery.
Area of Science:
- Optical Metrology
- Interferometry
- Surface Characterization
Background:
- White light scanning interferometry (WLSI) is crucial for 3D surface measurements.
- Dual-wavelength LEDs introduce spectral discontinuities, affecting fringe analysis.
- Existing methods struggle with accuracy due to these signal artifacts.
Purpose of the Study:
- To develop a novel algorithm for accurate 3D surface reconstruction in WLSI.
- To address the challenges posed by dual-wavelength LED interference signals.
- To enhance the repeatability and accuracy of WLSI measurements.
Main Methods:
- A new surface recovery algorithm utilizing Hilbert phase envelope and adjacent reference points.
- Analysis of interference signals from dual-wavelength white light emitting diodes (LEDs).
- Experimental verification of the proposed algorithm's reliability.
Main Results:
- The proposed algorithm effectively overcomes signal discontinuities from dual-wavelength LEDs.
- Improved accuracy in determining the zero-order fringe position.
- Successful 3D reconstruction of surfaces with enhanced precision.
Conclusions:
- The Hilbert phase envelope algorithm provides a robust solution for WLSI with dual-wavelength LEDs.
- This method significantly improves measurement accuracy and repeatability.
- The findings advance the application of LED-based WLSI for precise metrology.
