Logarithmic 3-Band Color Encoding: A Robust Method for Display and Comparison of Compositional Maps in Electron Probe X-Ray Microanalysis
Dale E. Newbury, David S. Bright
Digitally-recorded electron-excited x-ray maps are processed in a variety of ways to improve the visibility of features. Scaling of the recorded signal to match the 8-bit gray scale intensity range of a typical computer display system is almost always necessary. Inherent limitations of gray scale displays have led to other intensity encoding methods for x-ray maps, including clipping, histogram normalization, and pseudocolor scales. While feature visibility is improved by applying these scales, comparisons among image sets are difficult. Quantitative comparisons must be based upon standardized intensities corrected for background to produce intensity ratio (k-value) maps. To view these k-value maps effectively, a new method, logarithmic multiband color encloding, is presented. Three color bands are defined, starting with a dark primary color and grading to a bright pastel: blue = trace (0.001 to 0.01); green = minor (0.01 to 0.1) and red = major (0.1 to 1.0). Within each band, the color is assigned according to a logarithmic scale.
Microscopy and Microanalysis
compositional map, digital image, feature visibility, logarithmic 3-band color scale, logarithmic color scale, x-ray map
and Bright, D.
Logarithmic 3-Band Color Encoding: A Robust Method for Display and Comparison of Compositional Maps in Electron Probe X-Ray Microanalysis, Microscopy and Microanalysis
(Accessed December 4, 2023)