Results 261 to 270 of about 2,809,534 (302)

Phase shift selection for two-step generalized phase-shifting interferometry

Applied Optics, 2011
A phase shift selection method is proposed to design algorithms immune against phase shift errors in two-step generalized phase-shifting interferometry. A general formula for wavefront reconstruction error is derived, and its specific expressions for two common errors are also given.
Xiangfeng, Xu, Luzhong, Cai, Hongguang, Yuan, Qian, Zhang, Guangcan, Lu, Chu, Wang   +5 more
openaire   +2 more sources

Accurate Phase Shift Extraction for Generalized Phase-Shifting Interferometry

Chinese Physics Letters, 2010
An accurate phase shift extraction method for generalized phase-shifting interferometry is suggested. Based on the nearly random phase distribution of the diffraction field of the object, a singular formula is derived to calculate the unknown phase shift without the requirements of an iteration process or the selection of the correct value from two or ...
Xu Xian-Feng, Cai Lu-Zhong, Wang Yu-Rong, Li Dai-Lin   +3 more
openaire   +1 more source

Phase shifting for nonsinusoidal waveforms with phase-shift errors

Journal of the Optical Society of America A, 1995
In phase measurement systems that use phase shifting techniques, phase errors that are due to nonsinusoidal waveforms can be minimized by applying synchronous phase shifting algorithms with more than four samples. However, when the phase shift calibration is inaccurate, these algorithms cannot eliminate the effects of nonsinusoidal characteristics.
K. Hibino, K.G. Larkin, B. F. Oreb, D. I. Farrant   +3 more
openaire   +1 more source

Embedded phase shifting: Robust phase shifting with embedded signals

2015 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2015
We introduce Embedded PS, a new robust and accurate phase shifting algorithm for 3D scanning. The method projects only high frequency sinusoidal patterns in order to reduce errors due to global illumination effects, such as subsurface scattering and interreflections.
Daniel Moreno, Kilho Son, Gabriel Taubin
openaire   +1 more source

Algorithm immune to tilt phase-shifting error for phase-shifting interferometers

Applied Optics, 2000
As a phase shifter usually suffers from both translational and tilt-shift errors during shifting, so every pixel in the same interferogram will have a different phase-shift value. Thus nonlinear phase-measurement errors cannot be avoided, but even translational-shift error has been corrected effectively.
M, Chen, H, Guo, C, Wei
openaire   +2 more sources

Phase-shifting shearing interferometer

Optics Letters, 2001
A single-element phase-shifting interferometer has been developed based on the lateral shearing interferometer. This new interferometer requires no precise alignment, and the phase is continuously varied by changes in the voltage across a commercially available liquid-crystal phase retarder.
openaire   +2 more sources

Phase-shifting error and its elimination in phase-shifting digital holography

Optics Letters, 2002
We investigate the influence of phase-shifting error on the quality of the reconstructed image in digital holography and propose a method of error elimination for a perfect image. In this method the summation of the intensity bit errors of the reconstructed image is taken as an evaluation function for an iterative algorithm to find the exact phase ...
Cheng-Shan, Guo, Li, Zhang, Hui-Tian, Wang, Jun, Liao, Y Y, Zhu   +4 more
openaire   +2 more sources

Iterative phase-shifting algorithm immune to random phase shifts and tilts

Applied Optics, 2013
An iterative phase-shifting algorithm based on the least-squares principle is developed to overcome the random piston and tilt wavefront errors generated from the phase shifter. The algorithm iteratively calculates the phase distribution and the phase-shifting map to minimize the sum of squared errors in the interferograms.
Yi-Chun, Chen, Po-Chih, Lin, Chung-Min, Lee, Chao-Wen, Liang   +3 more
openaire   +2 more sources

Multichannel phase-shifted interferometer

Optics Letters, 1984
A new real-time interferometer based on diffraction phenomena is discussed. It consists of a point-diffraction interferometer fabricated on a transmission grating. The real-time data-analysis capability is achieved by simultaneously introducing a phase shift (piston) on the three separate channels of diffracted interferograms. Mathematical analysis and
openaire   +2 more sources

Random phase-shifting algorithm by constructing orthogonal phase-shifting fringe patterns

Applied Optics, 2017
The intensity distribution of fringe patterns becomes nonsinusoidal in real testing environments. Thus, the performance of existing phase shift extraction algorithms, which usually compute the desired phase shift by arccosine function or arcsine function, may be affected. In the presented paper, we report an arctangent-function-based technique to solve
Hubing, Du, Jingjing, Yan, Jianhua, Wang
openaire   +2 more sources