Open AccessFEM: feature‐enhanced map
Author(s) -
Afonine Pavel V.,
Moriarty Nigel W.,
Mustyakimov Marat,
Sobolev Oleg V.,
Terwilliger Thomas C.,
Turk Dusan,
Urzhumtsev Alexandre,
Adams Paul D.
Publication year - 2015
Publication title -
acta crystallographica section d
Language(s) - English
Resource type - Journals
ISSN - 1399-0047
DOI - 10.1107/s1399004714028132
Subject(s) - interpretability , sharpening , feature (linguistics) , noise (video) , series (stratigraphy) , artificial intelligence , histogram , pattern recognition (psychology) , signal (programming language) , algorithm , computer science , image (mathematics) , mathematics , geology , paleontology , philosophy , linguistics , programming language
A method is presented that modifies a 2 m F obs − D F model σ A ‐weighted map such that the resulting map can strengthen a weak signal, if present, and can reduce model bias and noise. The method consists of first randomizing the starting map and filling in missing reflections using multiple methods. This is followed by restricting the map to regions with convincing density and the application of sharpening. The final map is then created by combining a series of histogram‐equalized intermediate maps. In the test cases shown, the maps produced in this way are found to have increased interpretability and decreased model bias compared with the starting 2 m F obs − D F model σ A ‐weighted map.