Pattern standard deviationΒΆ

Quality metric that is computed from the standard deviation 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 = \sqrt{\frac{1}{WH-1}\sum\limits_{i=1}^W{\sum\limits_{j=1}^{H}{\left( I_{ij}-\bar{I} \right)^2}}}

where W and H are respectively the width and the height of the diffraction pattern, I_{ij} the intensity at pixel (i,*j*) and \bar{I}) the average intensity of all the pixels.

This quality index was used by Wright and Nowell [1] and Tao and Eades [2]. They summarized this quality index as:

  • Measure of the image contrast
  • Affected by contamination, gain, contrast settings and noise

Example on NiCoCrAlY sample

  1. Wright, S. I., & Nowell, M. M. (2006). EBSD image quality mapping. Microscopy Microanalysis, 12, 72-84.
  2. Tao, X., & Eades, A. (2005). Errors, artifacts, and improvements in ebsd processing and mapping. Microscopy Microanalysis, 11, 79-87.