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In order to increase the efficiency of phase retrieval,Wang proposed a high-speed moire phase retrieval method.But it is used only to measure the tiny object. In view of the limitation of Wang method,we proposed a dynamic three-dimensional…

Optics · Physics 2023-10-18 Canlin Zhou , Shuchun Si , XiaoLei Li , Zhenkun Lei , Yanjie Li , Chaorui Zhang

The stair phase coding patterns have been widely used to determine the fringe order for phase unwrapping of the wrapped phase in 3D shape measurement. Although the special coding sequence algorithm can achieve with a large number of…

Optics · Physics 2023-02-08 Xingyang Qi , Canlin Zhou , Yixiao Wang , Shuchun Si , Hui Li

In this fluid dynamics video, we present an overview of the most important results recently obtained in our group using an optical profilometric technique that allows for single-shot global measurement of free-surface deformations. This…

Fluid Dynamics · Physics 2010-10-19 P. Cobelli , G. Lagubeau , M. Chekroun , A. Przadka , A. Maurel , V. Pagneux , P. Petitjeans

The number of phase wraps in 2D wrapped phase map can be completely eliminated, or greatly reduced by frequency shifting. But the wraps usually cannot be optimally reduced using the conventional fast Fourier transform (FFT) because the…

Instrumentation and Detectors · Physics 2017-10-11 Minmin Wang , Guangliang Du , Canlin Zhou , Shuchun Si , Zhenkun Lei , XiaoLei Li , YanJie Li

Conventional dual-frequency fringe projection algorithm often suffers from phase unwrapping failure when the frequency ratio between the high frequency and the low one is too large. Zhang et.al. proposed an enhanced two-frequency…

Computer Vision and Pattern Recognition · Computer Science 2017-06-28 Guangliang Du , Minmin Wang , Canlin Zhou , Shuchun Si , Hui Li , Zhenkun Lei , Yanjie Li

Dynamic mode decomposition (DMD) provides a principled approach to extract physically interpretable spatial modes from time-resolved flow field data, along with a linear model for how the amplitudes of these modes evolve in time. Recently,…

Fluid Dynamics · Physics 2020-07-29 Aditya G. Nair , Benjamin Strom , Bingni W. Brunton , Steven L. Brunton

Fourier ptychographic microscopy (FPM) is a promising computational imaging technique with high resolution, wide field-of-view (FOV) and quantitative phase recovery. So far, a series of system errors that may corrupt the image quality of…

Image and Video Processing · Electrical Eng. & Systems 2023-03-29 An Pan , Aiye Wang , Junfu Zheng , Yuting Gao , Caiwen Ma , Baoli Yao

Ptychography involves a sample being illuminated by a coherent, localised probe of illumination. When the probe interacts with the sample, the light is diffracted and a diffraction pattern is detected. Then the probe or sample is shifted…

Numerical Analysis · Mathematics 2023-05-09 Mark Philip Roach

Background: Windowed Fourier decompositions (WFD) are widely used in measuring stationary and non-stationary spectral phenomena and in describing pairwise relationships among multiple signals. Although a variety of WFDs see frequent…

Quantitative Methods · Quantitative Biology 2019-01-30 Christopher K. Kovach , Phillip E. Gander

When subjected to monochromatic incident light a nanoparticle will emit light which then interferes with the incident beam. With sufficient contrast and sufficiently close to the particle this interference pattern may be recorded with a…

Optics · Physics 2019-02-26 T. G. Myers , H. Ribera , W. S. Bacsa

Ptychography is an imaging technique which involves a sample being illuminated by a coherent, localized probe of illumination. When the probe interacts with the sample, the light is diffracted and a diffraction pattern is detected. Then the…

Numerical Analysis · Mathematics 2023-01-31 Mark Iwen , Michael Perlmutter , Mark Philip Roach

In order to measure the radial displacements of facets on surface of a growing spherical Cu_{2-\delta}Se crystal with sub-nanometer resolution, we have investigated the reliability and accuracy of standard method of Fourier analysis of…

Optics · Physics 2009-11-13 Jadranko Gladic , Zlatko Vucic , Davorin Lovric

Deconvolution phase microscopy enables high-contrast visualization of transparent samples through reconstructions of their transmitted phases or refractive indexes. Herein, we propose a method to extend 2D deconvolution phase microscopy to…

Optics · Physics 2022-04-20 Herve Hugonnet , Mahn Jae Lee , Yongkeun Park

One-dimensional detrended fluctuation analysis (1D DFA) and multifractal detrended fluctuation analysis (1D MF-DFA) are widely used in the scaling analysis of fractal and multifractal time series because of being accurate and easy to…

General Physics · Physics 2007-05-23 Gao-Feng Gu , Wei-Xing Zhou

Two-Dimensional (2D) Discrete Fourier Transform (DFT) is a basic and computationally intensive algorithm, with a vast variety of applications. 2D images are, in general, non-periodic, but are assumed to be periodic while calculating their…

Computer Vision and Pattern Recognition · Computer Science 2016-03-17 Faisal Mahmood , Märt Toots , Lars-Göran Öfverstedt , Ulf Skoglund

Sample-induced aberrations and optical imperfections limit the resolution of fluorescence microscopy. Phase diversity is a powerful technique that leverages complementary phase information in sequentially acquired images with deliberately…

Fourier Ptychographic Microscopy (FPM) is a computational imaging method that is able to super-resolve features beyond the diffraction-limit set by the objective lens of a traditional microscope. This is accomplished by using synthetic…

Signal Processing · Electrical Eng. & Systems 2019-04-09 Michael Kellman , Emrah Bostan , Michael Chen , Laura Waller

The Depth from Defocus (DFD) imaging technique for measuring the size and number concentration of particles in a dispersed two-phase flow has up to now been restricted to relatively sparse particle densities and to identifying only…

Fluid Dynamics · Physics 2024-04-01 Rixin Xua , Zuojie Huanga , Wenchao Gonga , Wu Zhoua , Cameron Tropea

Fourier ptychographic microscopy (FPM) is a recently developed imaging modality that uses angularly varying illumination to extend a system performance beyond the limit defined by its optical elements. The FPM technique applies a novel…

Optics · Physics 2014-05-02 Xiaoze Ou , Roarke Horstmeyer , Changhuei Yang , Guoan Zheng

In this paper we present an algorithm for optical phase evaluation based on the wavelet transform technique. The main advantage of this method is that it requires only one fringe pattern. This algorithm is based on the use of a second…

Computational Engineering, Finance, and Science · Computer Science 2010-05-24 Mustapha Bahich , Mohamed Afifi , Elmostafa Barj