Results 211 to 220 of about 763,081 (262)

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

Reference phase shift determination in phase shifting interferometry

Optics and Lasers in Engineering, 1995
Abstract The phase shifting technique has recently seen application to many types of interferometers, including holographic, speckle and moire systems for strain analysis. In these applications, close control of the phase shifts may be impossible due to the effect of mechanical vibrations, and this presents difficulties when extracting the phase ...
K.E. Perry, J. McKelvie
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

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

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

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

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 speckle interferometry

Applied Optics, 1985
Speckle patterns have high frequency phase data, which make it difficult to find the absolute phase of a single speckle pattern; however, the phase of the difference between two correlated speckle patterns can be determined. This is done by applying phase-shifting techniques to speckle interferometry, which will quantitatively determine the phase of ...
openaire   +2 more sources

Phase-shifted Fresnel axicon

Optics Letters, 2012
We propose an optical element: a phase-shifted Fresnel axicon for generation of multiple Bessel beams. By giving a binary phase modulation to the standard Fresnel axicon, the proposed element is generated. The phase profile of the binary phase modulation is engineered to generate two and three Bessel beams of equal intensities.
Vijayakumar, A., Bhattacharya, Shanti
openaire   +3 more sources

Phase shift in dielectric reflection

Applied Optics, 1987
The phase shifts in external dielectric reflection were analyzed as a function of the incident angle. The contrast of the interference fringes formed between the incident and the reflected beams was considered. For the parallel mode the phase shift disappears between 45 degrees and the Brewster angle.
M C, Simon, J M, Simon, M T, Garea
openaire   +2 more sources