Orientation indexing

The inverse problem: recover the orientation that produced a measured pattern. Both examples index a synthetic two-grain scan projected from a de-ebsd master pattern, so the answer is known and the error can be quoted – a closed round trip that validates the conventions and the workflow, not experimental accuracy.

dictionary_indexing.py is the brute-force baseline: project the master at every orientation of a fundamental-zone sample and take the best normalized cross-correlation. spherical_indexing.py replaces that library with a spherical-harmonic cross-correlation over all of SO(3), whose cost does not depend on the crystal symmetry. Both end in gradient refinement, which is what takes a coarse grid hit to sub-degree accuracy.

Dictionary indexing: a synthetic scan, indexed and refined

Dictionary indexing: a synthetic scan, indexed and refined

Spherical indexing: cross-correlation over all of SO(3)

Spherical indexing: cross-correlation over all of SO(3)