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Automatic determination of diffuse‐peak positions and the centre of a diffraction pattern
Author(s) -
Wilkinson S. J.,
Hukins D. W. L.
Publication year - 1999
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889898016161
Subject(s) - diffraction , centroid , optics , gaussian , convolution (computer science) , resolution (logic) , beam (structure) , annulus (botany) , materials science , physics , mathematics , geometry , computer science , quantum mechanics , machine learning , artificial intelligence , artificial neural network , composite material
Correlation with a two‐dimensional Gaussian function was used to locate the positions of diffuse peaks in X‐ray diffraction patterns. The centre of a pattern was defined as the centroid of the image of the undeflected beam, found by convolution with a two‐dimensional Gaussian function. These methods were implemented using the IDL programing language. They were tested on diffraction patterns from systems containing oriented molecules of the protein collagen: collagen tape, elastoidin spicules and annulus fibrosus of intervertebral disc. Specimens were dusted with quartz to calibrate the diffraction patterns. These patterns were recorded on film, using a semi‐transparent beam stop to obtain an image of the undeflected beam, and digitized at a resolution of 105 µm. Intermolecular spacings, calculated from the distance between a peak and the centre of a pattern, were in good agreement with those determined previously.