Accurate nonlinear phase step estimation in phase shifting interferometry

2006 ◽  
Vol 266 (2) ◽  
pp. 638-647 ◽  
Author(s):  
Rajesh Langoju ◽  
Abhijit Patil ◽  
Pramod Rastogi
Keyword(s):  
Phase Shifting ◽  
Phase Step ◽  
Phase Shifting Interferometry ◽  
Nonlinear Phase

scholarly journals High-Accuracy Surface Profile Measurement Based on the Vortex Phase-Shifting Interferometry

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Donge Zhao ◽  
Chaozheng Jia ◽  
Yayun Ma ◽  
Xuefeng Yang ◽  
Bin Zhang ◽  
...  
Keyword(s):  
Phase Modulation ◽  
Spatial Light Modulator ◽  
Surface Profile ◽  
Phase Shifting ◽  
Profile Measurement ◽  
Vortex Beam ◽  
Light Modulator ◽  
Vortex Phase ◽  
Phase Shifting Interferometry ◽  
Nonlinear Phase

According to the principle of phase-shifting interferometry and spiral phase characteristics of the vortex beam, this article proposes a method for detecting the surface profile of a transparent object, in which the +1 order vortex beam is generated by a spatial light modulator and is taken as the reference light. The influence of the nonlinear phase modulation characteristics of the spatial light modulator on the measurement precision is studied. The results show that nonlinear phase modulation has a great impact on the measurement. Then, the vortex lights with initial phases of 0, π/2, π, and 3π/2 are used to measure the H-type thin film sample based on the Twyman-Green interference system after correcting the nonlinear phase modulation characteristics. The experimental results show that the measurement error of the surface profile to an object with the theoretical value of 20 nm is 1.146 nm, and the feasibility of the optical vortex phase-shifting technique used to measure the surface profile of an object is verified.

Comparative analysis of interferogram noise filtration using wavelet transform and spin filtering algorithms

2010 ◽  
Vol 18 (2) ◽  
Author(s):  
B. Zielinski ◽  
K. Patorski
Keyword(s):  
Wavelet Transform ◽  
Wavelet Decomposition ◽  
Lattice Site ◽  
Phase Shifting ◽  
Discrete Wavelet ◽  
Spin Filter ◽  
Phase Step ◽  
Phase Shifting Interferometry ◽  
2D Histogram ◽  
Spin Filtering

AbstractThe aim of this paper is to analyze 2D fringe pattern denoising performed by two chosen methods based on quasi-1D two-arm spin filter and 2D discrete wavelet transform (DWT) signal decomposition and thresholding. The ultimate aim of this comparison is to estimate which algorithm is better suited for high-accuracy measurements by phase shifting interferometry (PSI) with the phase step evaluation using the lattice site approach. The spin filtering method proposed by Yu et al. (1994) was designed to minimize possible fringe blur and distortion. The 2D DWT also presents such features due to a lossless nature of the signal wavelet decomposition. To compare both methods, a special 2D histogram introduced by Gutman and Weber (1998) is used to evaluate intensity errors introduced by each of the presented algorithms.

Phase-shifting interferometry in the presence of nonlinear phase steps, harmonics, and noise

2006 ◽  
Vol 31 (8) ◽  
pp. 1058 ◽  
Author(s):  
Rajesh Langoju ◽  
Abhijit Patil ◽  
Pramod Rastogi
Keyword(s):  
Phase Shifting ◽  
Phase Shifting Interferometry ◽  
Nonlinear Phase
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