Application of a Three-Dimensional Maximum-Entropy Method to Processing Sections of Three-Dimensional NMR Spectra

The study of the spatial characteristics of soil pore networks is essential to obtain different parameters that will be useful in developing simulation models for a range of physical, chemical, and biological processes in soils. Over the last decade, major technological advances in X-ray computed tomography (CT) have allowed for the investigation and reconstruction of natural porous soils at very fine scales. Delimiting the pore network (pore space) from the CT soil images applying image binarization methods is a critical step. Different binarization methods can result in different spatial distributions of pores influencing the connectivity metrics used in the models. A combined global & local 2D segmentation method called &#8220;Combining Singularity-CA method&#8221; was successfully applied improving pore space detection. This method combines a local scaling method (Singularity-CA method) with a global one (Maximum Entropy method). The Singularity-CA method, based on fractal concepts, creates singularity maps, and the CA (Concentration Area) method is used to define local thresholds that can be applied to binarize CT soil images. Combining Singularity-CA (2D) method obtains better performance than the Singularity-CA and the Maximum Entropy method applied individually to the soil images. A new three dimensional binarization method is presented in this work. It combines the 3D Singularity-CV (Concentration Volume) method and a global one to improve 3D pore space detection. Porosity and connectivity metrics of soil pore spaces are calculated and compared to other segmentation methods. &#160; Acknowledgements: The authors acknowledge the support from Project No. PGC2018-093854-B-I00 of the "Ministerio de Ciencia, Innovaci&#243;n y Universidades" of Spain and the funding from the "Comunidad de Madrid" (Spain), Structural Funds 2014-2020 512 (ERDF and ESF), through project AGRISOST-CM S2018/BAA-4330.

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ENIGMA: maximum-entropy method program package for huge systems

Journal of Applied Crystallography ◽

10.1107/s002188980200050x ◽

2002 ◽

Vol 35 (2) ◽

pp. 282-286 ◽

Cited By ~ 98

Author(s):

Hiroshi Tanaka ◽

Masaki Takata ◽

Eiji Nishibori ◽

Kenichi Kato ◽

Takashi Iishi ◽

...

Keyword(s):

Maximum Entropy ◽

Message Passing ◽

Message Passing Interface ◽

Maximum Entropy Method ◽

Computing Time ◽

Three Dimensional ◽

Entropy Method ◽

Program Package ◽

Fast Fourier Transformation ◽

Memory Space

ENIGMA(Electron and Nuclear Image Generator by Max-ent Analysis) is a program package to evaluate three-dimensional electron and nuclear density from X-ray and neutron diffraction data by using the maximum-entropy method (MEM). Compared with the previous program packageMEED,ENIGMAsaves computing time and frees memory space at the same time by employing parallel data processing. The fast Fourier transformation (FFT) technique is also implemented. As a consequence of these improvements, the MEM analysis byENIGMAbecomes applicable to huge systems, such as proteins and polymers, when the phased structure factors are provided. The package is transferable to a wide variety of parallel computers, because it is written in Fortran 90 and a standard message-passing interface (MPI).

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