Phase reconstruction with simultaneous correction of spherical and astigmatic aberrations by three-dimensional Fourier filtering method

2003 ◽  
Vol 35 (1) ◽  
pp. 51-54 ◽  
Author(s):  
Tadahiro Kawasaki ◽  
Yoshizo Takai
Keyword(s):  
Three Dimensional ◽  
Phase Reconstruction ◽  
Filtering Method ◽  
Fourier Filtering

Wave field restoration using three-dimensional Fourier filtering method

2001 ◽  
Vol 90 (1) ◽  
pp. 47-59 ◽  
Author(s):  
Tadahiro Kawasaki ◽  
Yoshizo Takai ◽  
Takashi Ikuta ◽  
Ryuichi Shimizu
Keyword(s):  
Wave Field ◽  
Three Dimensional ◽  
Filtering Method ◽  
Fourier Filtering

Novel, Fourier Filtering Method That Reuses Interference-Patterned Spectra to Extend the Calibration Set for Thickness Determination

2006 ◽  
Vol 60 (2) ◽  
pp. 162-167 ◽  
Author(s):  
Éva Jeszenszky ◽  
László Kocsányi ◽  
Attila Barócsi ◽  
Péter Richter
Keyword(s):  
Filtering Method ◽  
Thickness Determination ◽  
Fourier Filtering

Study of a Fast Windowed Fourier Filtering Method for Interference Fringes

2014 ◽  
Vol 34 (6) ◽  
pp. 0612008
Author(s):  
郭媛 Guo Yuan ◽  
毛琦 Mao Qi ◽  
陈小天 Cheng Xiaotian ◽  
王娜 Wang Na ◽  
赵丽娜 Zhao Lina
Keyword(s):  
Filtering Method ◽  
Interference Fringes ◽  
Fourier Filtering

scholarly journals A flexible three-dimensional stratocumulus, cumulus and cirrus cloud generator (3DCLOUD) based on drastically simplified atmospheric equations and the Fourier transform framework

2014 ◽  
Vol 7 (4) ◽  
pp. 1779-1801 ◽  
Author(s):  
F. Szczap ◽  
Y. Gour ◽  
T. Fauchez ◽  
C. Cornet ◽  
T. Faure ◽  
...  
Keyword(s):  
Water Content ◽  
Three Dimensional ◽  
Atmospheric Equations ◽  
Cloudy Atmosphere ◽  
Fourier Filtering ◽  
Ice Water Content ◽  
Inhomogeneity Parameter ◽  
The Mean ◽  
The Fourier Transform ◽  
Ice Water

Abstract. The 3DCLOUD algorithm for generating stochastic three-dimensional (3-D) cloud fields is described in this paper. The generated outputs are 3-D optical depth (τ) for stratocumulus and cumulus fields and 3-D ice water content (IWC) for cirrus clouds. This model is designed to generate cloud fields that share some statistical properties observed in real clouds such as the inhomogeneity parameter ρ (standard deviation normalized by the mean of the studied quantity), the Fourier spectral slope β close to −5/3 between the smallest scale of the simulation to the outer Lout (where the spectrum becomes flat). Firstly, 3DCLOUD assimilates meteorological profiles (humidity, pressure, temperature and wind velocity). The cloud coverage C, defined by the user, can also be assimilated, but only for stratocumulus and cumulus regime. 3DCLOUD solves drastically simplified basic atmospheric equations, in order to simulate 3-D cloud structures of liquid or ice water content. Secondly, the Fourier filtering method is used to constrain the intensity of ρ, β, Lout and the mean of τ or IWC of these 3-D cloud structures. The 3DCLOUD model was developed to run on a personal computer under Matlab environment with the Matlab statistics toolbox. It is used to study 3-D interactions between cloudy atmosphere and radiation.

scholarly journals Time-efficient filtering method for three-dimensional point clouds data of tunnel structures

2018 ◽  
Vol 10 (5) ◽  
pp. 168781401877315 ◽  
Author(s):  
Xiangyang Xu ◽  
Hao Yang ◽  
Ingo Neumann
Keyword(s):  
Three Dimensional ◽  
Point Clouds ◽  
Filtering Method

scholarly journals Direct information retrieval after 3D reconstruction in grating-based X-ray phase-contrast computed tomography

2018 ◽  
Vol 25 (4) ◽  
pp. 1222-1228 ◽  
Author(s):  
Zhao Wu ◽  
Kun Gao ◽  
Zhili Wang ◽  
Chenxi Wei ◽  
Faiz Wali ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Information Retrieval ◽  
Phase Contrast ◽  
Three Dimensional ◽  
Large Field ◽  
Computational Time ◽  
Imaging Method ◽  
Phase Reconstruction ◽  
Phase Information ◽  
X Ray

Grating-based X-ray differential phase-contrast imaging has attracted a great amount of attention and has been considered as a potential imaging method in clinical medicine because of its compatibility with the traditional X-ray tube source and the possibility of a large field of view. Moreover, phase-contrast computed tomography provides three-dimensional phase-contrast visualization. Generally, two-dimensional information retrieval performed on every projection is required prior to three-dimensional reconstruction in phase-contrast computed tomography. In this paper, a three-dimensional information retrieval method to separate absorption and phase information directly from two reconstructed images is derived. Theoretical derivations together with numerical simulations have been performed to confirm the feasibility and veracity of the proposed method. The advantages and limitations compared with the reverse projection method are also discussed. Owing to the reduced data size and the absence of a logarithm operation, the computational time for information retrieval is shortened by the proposed method. In addition, the hybrid three-dimensional images of absorption and phase information were reconstructed using an absorption reconstruction algorithm, hence the existing data pre-processing methods and iterative reconstruction algorithms in absorption reconstruction may be utilized in phase reconstruction immediately.

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