deformation is 0.7 um [99Gee]. The EBSD information depth for this material is estimated to be 
about 0.04 um at 20 kV [93Joy], [98Ren]. nz 
Pattern Quality as a Measure for Preparation Quality 
A reliable automatic EBSD scan is only possible if the EBSPs are of good quality (contrast) so that 
they can be recognized by the computer. Lines in the pattern are transformed by Hough transform in 
points in the Hough space for easier and faster location (Fig. 3) [92Kri]. The average height of the 
detected peaks in the Hough transform can be used as a quality parameter [94 War], [98TSL]. 
(X4,Yı) 
P {ad 
Bays) 
) PQl = 205 
Fig. 3: Line detection for indexing of EBSP 
It should be noticed that the so defined pattern quality index (PQI) is also dependent on other 
factors like crystal system, orientation, etc. Nevertheless it is a very good measure, even not 
absolute, for the strain in the diffraction volume of material (Fig. 4). For automatic scans a PQI 
above 80 is desirable. But depending on the crystal symmetry and orientation pattern with much 
lower PQI can be indexed correctly as well. 
MM 
mate 
best 
Wh 
ny 
may 
Fig. 4: EBSP of different quality index due to different preparation (Iron, 20 kV) a 
Preparation for EBSD 
Different materials were prepared so that EBSPs of good quality were obtained. The test materials | N 
differ in hardness, which strongly influences the preparation behaviour, and also in their EBSD a 
information depth. In Fig 5 they are plotted by hardness versus the escape depth of the . 
356