scholarly journals Potential in reducing scan times of HARDI by accurate correction of the cross-term in a hemispherical encoding scheme

2009 ◽  
Vol 29 (6) ◽  
pp. 1386-1394 ◽  
Author(s):  
Kuan-Hung Cho ◽  
Chun-Hung Yeh ◽  
Yi-Ping Chao ◽  
Jiun-Jie Wang ◽  
Jyh-Horng Chen ◽  
...  
Keyword(s):  
Cross Term ◽  
Encoding Scheme ◽  
The Cross

Diffusion dépolarisée Rayleigh par des molécules anisotropes: calcul analytique des contributions propres, collisionnelles et croisées pour divers potentiels

1989 ◽  
Vol 67 (5) ◽  
pp. 525-531 ◽  
Author(s):  
B. Dumon ◽  
J. Berrue ◽  
A. Chave ◽  
A. Barreau
Keyword(s):  
Pair Correlation ◽  
Analytical Calculation ◽  
Preceding Paper ◽  
Dipole Approximation ◽  
Intermolecular Potential ◽  
Polarizability Tensor ◽  
Cross Term ◽  
Quadrupolar Moment ◽  
Induced Dipole ◽  
The Cross

In a preceding paper, a new analytical calculation of the integrated Rayleigh light scattered intensities, taking into account the permanent anisotropy in the collisionnal polarizability tensor, has been developped. The contributions of orientational pair correlation collision induced light scattering and the cross term have been evaluated in the first order dipole induced dipole approximation, at low density in the center–center polarizability scheme. In this article, from these analytical expansions, we calculate contribution values in N2, CO2, Cl2, and O2 to the scattered intensities. The intermolecular potential is represented by a two (or three)-site Lennard–Jones model without (or with) a quadrupolar moment. We show that these new analytical calculations lead to important corrections of up to 30% for the cross term in O2, and that the potential choice plays an essential role. These results are compared with experimental data and to other studies.

The Certification for Inevitability of Cross-Term in WVD

2014 ◽  
Vol 1030-1032 ◽  
pp. 1930-1933 ◽  
Author(s):  
Zhong Hu Yuan ◽  
Man Yang Xu ◽  
Xiao Xuan Qi
Keyword(s):  
Mathematical Method ◽  
Frequency Analysis ◽  
Cross Term ◽  
Time Frequency Analysis ◽  
Important Method ◽  
Time Frequency ◽  
Multicomponent Signal ◽  
Mathematical Properties ◽  
The Cross

WVD has become an important method for time-frequency analysis because of its mathematical properties. In fact, however, cross-term disturbs its application seriously when the multicomponent signal existed. Now increasing people is going to find pure mathematical method to deal with the cross-term in WVD. But this paper will prove the inevitability of cross-term in WVD.

Mask filtering to the Wigner-Ville distribution

Geophysics ◽  
2021 ◽  
pp. 1-30
Author(s):  
Haifa Alsalmi ◽  
Yanghua Wang
Keyword(s):  
High Resolution ◽  
Seismic Data ◽  
Energy Concentration ◽  
Cross Term ◽  
Time Frequency ◽  
Stationary Signals ◽  
Spectral Analysis Method ◽  
The Cross ◽  
Data Adaptive ◽  
3D Seismic Data

The Wigner-Ville distribution (WVD) is a high-resolution time-frequency spectral analysis method for non-stationary signals, and yet it suffers from cross-term interference among signal components. We proposed applying a masking filter directly to the WVD time-frequency spectrum to suppress the cross-term interference. Conventional methods for suppressing the interference include the smoothed-pseudo WVD (SP-WVD) method, which incorporates smooth filtering in both time and frequency directions. We exploited the SP-WVD spectrum as a reference to design the masking filter, and thus the mask filtered WVD (MF-WVD) procedure is data adaptive. The MF-WVD method preserves the high-resolution energy concentration in the spectrum portrayed by the standard WVD, while suppressing the cross-term interference cleanly like in the SP-WVD method. Applying the MF-WVD method to field 3D seismic data generates high-resolution spectral cubes for various frequencies, and these spectral cubes may be used intuitively for detecting reservoir-related characteristics.

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