Pattern averageΒΆ

Quality metric that is computed from the average of all the pixels in the diffraction pattern. The pixels with a value of zero are ignored, so that the pixels removed from the Mask disc operation are ignored.

Q = \frac{1}{W\cdot H} \sum\limits_{i=0}^{W}{\sum\limits_{j=0}^{H}{I_{ij}}}

where W is the width of the pattern, H is the height of the pattern and I_{ij} the pixel value at position (i, j).

This quality index was used by Wright and Nowell [1]. They summarized this quality index as:

  • a measure of the overall backscatter yield
  • related to surface topography
  • show scratches, microtwins and small strain levels
  • affected by contamination, gain, contrast settings and current drift

Example on NiCoCrAlY sample

  1. Wright, S. I., & Nowell, M. M. (2006). EBSD image quality mapping. Microscopy Microanalysis, 12, 72-84.