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Speckle-noise-reduction method of projecting interferometry fringes based on power spectrum density
Liping Zhou1, Jianghong Gan, Xiaojun Liu
1The State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, China.
Applied Optics
|October 12, 2012
Summary
A new method reduces speckle noise in fringe projection surface inspection using power spectrum density (PSD) thresholding. This technique enhances fringe pattern clarity for improved 3D surface measurements.
Area of Science:
- Optical Metrology
- Image Processing
Background:
- Fringe projection techniques are vital for noncontact, high-resolution 3D surface inspection.
- Speckle noise in fringe patterns significantly degrades measurement accuracy.
Purpose of the Study:
- To introduce a novel method for speckle noise reduction in fringe projection interferometry.
- To enhance the quality of fringe patterns for more reliable surface inspection.
Main Methods:
- Calculation of Power Spectrum Density (PSD) from the Fourier transform of fringe patterns.
- Application of PSD thresholding to design a filter for speckle noise removal.
- Utilizing inverse Fourier transform to reconstruct the noise-reduced image.
Main Results:
- The proposed PSD thresholding method effectively reduces speckle noise.
- Experimental validation demonstrates the feasibility and high effectiveness of the technique.
- Improved fringe pattern quality leads to more accurate surface measurements.
Conclusions:
- The PSD thresholding method offers a robust solution for speckle noise in fringe projection.
- This technique is crucial for advancing the accuracy and reliability of optical surface inspection.
- The method has significant implications for industrial surface metrology and quality control.
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