*

Improved accuracy

large acceptance angle => stable indexing
sufficient number of consistent bands => reliability
bands from several zone axes => reliabilty
less pattern coarsening or pixel binning => precision
dynamic correction of scan field rotation with focus (that does not affect grain orientation measurement but distorts crystal orientation maps only).

*

High speed of measurement reduces demands on long-term stability of the SEM (ORKID software at present 200,000 orientations/hour).

Digital cameras enable pixel binning (combination of several pixels on the chip => increases sensitivity, reduces volume of data transfer, increases speed). A high speed of about 750 pattern/sec is presently achieved with a Gigabit Ethernet interface.

If intragranular structure is of no concern, it is sufficient to acquire the orientation of each grain only once, and iterative mesh refinement has proven very effective by concentrating measurement along grain boundaries. Mesh refinement is inadequate if the microstructure contains twinned grains or if a broad grain size distribution is present.R.A. Schwarzer, Microscopy and Microanalysis 5, Suppl. 2 (1999) 242-243 .

*

Low crystal symmetry is still a challenge.

*

Fast phase discrimination has to be expanded to fast phase identification.

*

Improved quantification of pattern quality parameter
=> correlation with stress, dislocation density.

=>

Radon transform and peak shape analysis,
Evaluation of band intensities.

*

3-D reconstruction of the microstructure at subgrain resolution by by consecutive sectioning. An excellent depth resolution is achieved with a dual-beam SEM which is a conventional SEM attached with an additional FIB (field ion beam source) column.