scholarly journals Computer-Oriented Real Spherical Harmonics for Texture and Properties Analyses

1996 ◽  
Vol 28 (1-2) ◽  
pp. 93-104 ◽  
Author(s):  
O. Raymond ◽  
L. Fuentes ◽  
J. I. Gómez

An algorithm system to generate symmetric real functional bases for Quantitative Texture Analysis (QTA) is presented. A review of the analytical conditions to be satisfied by the considered functions is given. Suitable two- and three-dimensional bases are proposed. All crystal and sample point groups are analyzed. Computer implementation of the suggested algorithms is straightforward.

Author(s):  
S. S. Cho ◽  
K. C. Park ◽  
R. Kolman

Computer implementation of the new algorithm developed in [1, 2, 3] and its numerical performance is presented, with detailed discussions of the element-by-element decomposition of the extensional and shear components and step-by-step algorithmic procedures. Numerical results as applied to wave propagating through cracked plane stress problems, three-dimensional problems and elasto-plastic problems illustrate high-fidelity of the present algorithm compared with existing ones, and the new algorithm is implemented into an open source research code TAHOE[4] code along with the further computational performance.


2014 ◽  
Vol 533 ◽  
pp. 415-420 ◽  
Author(s):  
Wei Fang Liu ◽  
Xu Wang ◽  
Hong Xia

This study investigated three-dimensional (3D) texture as a possible diagnostic marker of Alzheimers disease (AD). Methods: T1-weighted MRI of 18 AD patients, 18 Mild Cognitive Impairment (MCI) patients and 18 normal controls (NC) were selected.3D Texture parameters of the corpus callosum,including contrast, inverse difference moment , entropy, short run emphasis, long run emphasis, grey level nonuniformity, run length nonuniformity and fraction were extracted from the gray level co-occurrence matrix and run length matrix. Finally statistic significance was tested among three groups, and the correlations between parameters and Mini-Mental State Examination (MMSE) scores were calculated. Results: The results showed that the 3D texture features had significant differences (p<0.05) among three groups except grey level nonuniformity and run length nonuniformity that the difference was not significant (p>0.05) between MCI and NC or AD and MCI , and they were correlated with MMSE scores.Conclusions: 3D texture analysis can reflect the pathological changes of corpus callosum in patients with AD and MCI, and it may be helpful to AD early diagnosis.


2019 ◽  
Vol 34 (2) ◽  
pp. 97-102
Author(s):  
M. A. Rodriguez ◽  
T. T. Amon ◽  
J. J. M. Griego ◽  
H. Brown-Shaklee ◽  
N. Green

Advancements in computer technology have enabled three-dimensional (3D) reconstruction, data-stitching, and manipulation of 3D data obtained on X-ray imaging systems such as micro-computed tomography (μ-CT). Likewise, intuitive evaluation of these 3D datasets can be enhanced by recent advances in virtual reality (VR) hardware and software. Additionally, the generation, viewing, and manipulation of 3D X-ray diffraction datasets, such as pole figures employed for texture analysis, can also benefit from these advanced visualization techniques. We present newly-developed protocols for porting 3D data (as TIFF-stacks) into a Unity gaming software platform so that data may be toured, manipulated, and evaluated within a more-intuitive VR environment through the use of game-like controls and 3D headsets. We demonstrate this capability by rendering μ-CT data of a polymer dogbone test bar at various stages of in situ mechanical strain. An additional experiment is presented showing 3D XRD data collected on an aluminum test block with vias. These 3D XRD data for texture analysis (χ, ϕ, 2θ dimensions) enables the viewer to visually inspect 3D pole figures and detect the presence or absence of in-plane residual macrostrain. These two examples serve to illustrate the benefits of this new methodology for multidimensional analysis.


2019 ◽  
Vol 36 (7) ◽  
pp. 2237-2243
Author(s):  
Cyril F Reboul ◽  
Simon Kiesewetter ◽  
Dominika Elmlund ◽  
Hans Elmlund

Abstract Motivation No rigorous statistical tests for detecting point-group symmetry in three-dimensional (3D) charge density maps obtained by electron microscopy (EM) and related techniques have been developed. Results We propose a method for determining the point-group symmetry of 3D charge density maps obtained by EM and related techniques. Our ab initio algorithm does not depend on atomic coordinates but utilizes the density map directly. We validate the approach for a range of publicly available single-particle cryo-EM datasets. In straightforward cases, our method enables fully automated single-particle 3D reconstruction without having to input an arbitrarily selected point-group symmetry. When pseudo-symmetry is present, our method provides statistics quantifying the degree to which the 3D density agrees with the different point-groups tested. Availability and implementation The software is freely available at https://github.com/hael/SIMPLE3.0.


1982 ◽  
Vol 5 (2) ◽  
pp. 95-125 ◽  
Author(s):  
C. Esling ◽  
E. Bechler-Ferry ◽  
H. J. Bunge

Bunge's and Roe's three-dimensional texture analysis methods, although both founded on harmonic analysis, show some differences between the various mathematical techniques used.This paper establishes the correspondence relation between the respective mathematical techniques allowing one to compare works done in either variant. Taking the latest developments in three dimensional texture analysis into account, the correspondence relations hold for the odd degrees l as well as for the even ones.Finally numerical tables give the extension of the symmetry coefficients B:l4mμ (after Bunge) and R4nμl (after Roe) to all the degrees l of the series expansion, even and odd, including l = 34.


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