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Title: Incorrect support and missing center tolerances of phasing algorithms

In x-ray diffraction microscopy, iterative algorithms retrieve reciprocal space phase information, and a real space image, from an object's coherent diffraction intensities through the use of a priori information such as a finite support constraint. In many experiments, the object's shape or support is not well known, and the diffraction pattern is incompletely measured. We describe here computer simulations to look at the effects of both of these possible errors when using several common reconstruction algorithms. Overly tight object supports prevent successful convergence; however, we show that this can often be recognized through pathological behavior of the phase retrieval transfer function. Dynamic range limitations often make it difficult to record the central speckles of the diffraction pattern. We show that this leads to increasing artifacts in the image when the number of missing central speckles exceeds about 10, and that the removal of unconstrained modes from the reconstructed image is helpful only when the number of missing central speckles is less than about 50. In conclusion, this simulation study helps in judging the reconstructability of experimentally recorded coherent diffraction patterns.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [2] ;  [5]
  1. Stony Brook Univ., Stony Brook, NY (United States); Univ. College London (United Kingdom)
  2. Stony Brook Univ., Stony Brook, NY (United States)
  3. Stony Brook Univ., Stony Brook, NY (United States); Max Planck Institute for Medical Research, Heidelberg (Germany)
  4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  5. Stony Brook Univ., Stony Brook, NY (United States); Northwestern Univ., Evanston, IL (United States); Argonne National Lab., Argonne, IL (United States)
Publication Date:
OSTI Identifier:
1165053
Report Number(s):
DOE-RFSUNY--46128
Journal ID: ISSN 1094-4087; OPEXFF
Grant/Contract Number:
FG02-04ER46128
Type:
Accepted Manuscript
Journal Name:
Optics Express
Additional Journal Information:
Journal Volume: 18; Journal Issue: 25; Journal ID: ISSN 1094-4087
Publisher:
Optical Society of America (OSA)
Research Org:
Stony Brook Univ., Stony Brook, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY X-ray imaging; diffraction; image reconstruction techniques; noise in imaging systems