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Analysis of low-coherence interference fringes by the Kalman filtering method
Igor Gurov1, Elena Ermolaeva, Alexey Zakharov
1Saint Petersburg Institute of Fine Mechanics and Optics (Technical University), 14 Sablinskaya Street, Saint Petersburg 197101, Russia. ig@spb.runnet.ru
Summary
This study introduces a Kalman filtering method to improve low-coherence interferometry for rough surface measurement. The technique enhances signal processing, overcoming light scattering issues for more accurate results.
Area of Science:
- Optical metrology
- Signal processing
- Surface characterization
Background:
- Low-coherence interferometry enables noncontact measurement of surface relief.
- Light scattering from rough surfaces distorts interferometric signals.
- Accurate processing of noisy fringe data is crucial for reliable measurements.
Purpose of the Study:
- To develop a robust method for processing noisy low-coherence interferometric fringes.
- To mitigate signal distortion caused by light scattering.
- To improve the accuracy and speed of rough-surface relief measurement.
Main Methods:
- Utilizing a stochastic fringe model for signal representation.
- Applying Kalman filtering for dynamic processing of fringe data.
- Employing prediction error for real-time correction of fringe envelope and phase estimates.
Main Results:
- Demonstrated immunity of the Kalman filtering method to noise.
- Achieved optimal evaluation of low-coherence fringes.
- Showcased enhanced data-processing speed compared to traditional methods.
Conclusions:
- Kalman filtering offers a powerful solution for noisy low-coherence interferometry.
- The proposed method improves the reliability of rough-surface measurements.
- This technique enhances measurement definition and accuracy in optical metrology.