Electron Diffraction Processing

Processing of electron diffraction patterns is done with the iplt_diff and iplt_diff_merge stand-alone python executable. It is run from the main project directory, which contains the individual image directories plus the project.xml file (see ex/diff/ProjectSetup and Example XML File).

The processing logic of individual diffraction patterns is closely mirrored in the individual subroutines of the iplt_diff tool, and consists of:

  1. Automatic lattice determination (search, with beamstop masking and origin determination)
  2. Manual verification of the automatically determined lattice; potential re-indexing
  3. Extraction of individual reflection values, such as gaussian fit parameters and background (extract)
  4. Integration of spots with background correction (integrate)
  5. Determination of tilt geometry and conversion of reflection values to intensity and sigma (tilt)
  6. Symmetrization (sym)

After processing each diffraction pattern, the scaling, merging and lattice line discretization takes place with iplt_diff_merge

  1. Scaling to a reference (scale)
  2. Merging to lattice lines (merge)
  3. Discretizaton (fit)
  4. Refinement of scale and/or tilt (refine)

Graphical checking and verification is done with giplt_diff.