This paper describes a new form of orientation imaging microscopy: Adaptive Orientation Imaging Microscopy or AOIM. In standard OIM experiments the local orientation of the crystal lattice is determined with respect to a suitable reference frame by acquiring and indexing electron back-scattering (EBS) patterns on a square or hexagonal grid of sampling points. Since its invention, OIM has been extensively used to characterize polycrystalline materials. With the fast development of computers and CCD camera systems in the past few years, the standard OIM can now acquire and index of the order of 4000 EBS patterns per hour.
In a typical OIM experiment one is usually interested in either the overall texture of. the sample, or in the types and relative frequencies of grain boundaries. In the former case the proper way of acquiring orientation data involves the use of an equidistant grid of sampling points. In the latter case, however, a large fraction of the acquisition time is wasted sampling the grain interior, which does not provide any information about the grain boundaries.