  High angular resolution electron backscatter diffraction (HR-EBSD) affords an
increase in angular resolution, as compared to 'conventional' Hough transform
based EBSD, of two orders of magnitude, enabling measurements of relative
misorientations of 1E-4 rads (~ 0.006 {\deg}) and changes in (deviatoric)
lattice strain with a precision of 1E-4. This is achieved through direct
comparison of two or more diffraction patterns using sophisticated
cross-correlation based image analysis routines. Image shifts between zone axes
in the two-correlated diffraction pattern are measured with sub-pixel precision
and this realises the ability to measure changes in interplanar angles and
lattice orientation with a high degree of sensitivity. These shifts are linked
to strains and lattice rotations through simple geometry. In this manuscript,
we outline the basis of the technique and two case studies that highlight its
potential to tackle real materials science challenges, such as deformation
patterning in polycrystalline alloys.
