A Simple Phase Unwrapping Approach Based on Filtering by Windowed Fourier Transform (II)

Qian Kemao; Seah Hock Soon

doi:10.4028/www.scientific.net/KEM.326-328.67

Paper Titles

Application of Wavelet Transform for Analyzing Instantaneous Contour of Continual Deformation Object
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Analysis of Simultaneous Velocity and Density Distributions for High-Speed CO₂ Flow Using Particle Image Velocimetry and Digital Speckle Tomography
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Stress Analysis of Composite Material Embedded with Optical Fiber Sensor
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Residual Deformation Measurement of Laser Weldment Using the Laser Interferometry
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A Simple Phase Unwrapping Approach Based on Filtering by Windowed Fourier Transform (II)
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Development of Combined Optical System for Thermal Analysis of Impinging Flames
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Application of Determination of Principal-Stress Directions by Color Phase Shifting Technique to Model Containing Isotropic Points
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Strain Analysis on Porous TiNi SMA Using SEM Moiré Method
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Image Reconstruction from Incomplete Data and Its Applications in Experimental Mechanics
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A Simple Phase Unwrapping Approach Based on Filtering by Windowed Fourier Transform (II)

Abstract:

Phase unwrapping is an important and challenging process in optical interferometry. Difficulties in phase unwrapping are usually caused by either noise (“bad” pixels) or invalid areas (“bad” regions). If the “bad” pixels can be removed, the problems due to the noise are solved. Further, if the “bad” regions can be identified, they can be avoided in phase unwrapping. In our previous work the noise can be successfully removed using a windowed Fourier transform [Optics and Lasers Technology, 37:458-462 (2005)]. In this paper we will show that the invalid areas can be identified by the same windowed Fourier transform. Thus a single windowed Fourier transform is able to process both “bad” pixels and “bad” regions simultaneously, which makes the phase unwrapping simple and effective.