Spherical EBSD

Spheres, or more usually spherical surfaces, are important in electron backscatter diffraction. Both electron backscatter patterns (EBSPs) and pole figure texture data are more accurately represented on the spherical surface, S-2; and unit quaternions, which are the optimal method for orientation calculations, exist on the surface of the hypersphere, S-3. This paper is split into two distinct parts. The first shows a little of the history of the EBSP technique, including the use of spheres to assemble a spherical Kikuchi map (SKM) and as calibration artefacts. The second part relates new developments in the analysis of EBSPs on the surface of a sphere, a new spherical Hough transform and ideas for fully automatic, ab initio analysis of unknown phases using collections of EBSPs assembled as spherical Kikuchi maps.