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The Use of Colour in Image Enhancement of X-Ray Microtomographs

Tjahjadi T & Bowen DK

Journal of X-Ray Science & Technology, vol 1, 1989, 171-189


This paper examines the effectiveness in displaying monochrome images as colour images and presents a pseudo-colour enhancement technique for enhancing features in x-ray microtomographs of biological and inorganic materials. The technique utilises the knowledge that the grey levels (intensities) in the image represent the linear absorption coefficients of the elements in the material and groups pixels with similar grey levels and hence similar absorption coefficients into a region, with a colour representing the region. Since each colour in the pseudo-colour enhanced image represents a similar region, e.g. an element or phase in the material, its microstructure can easily be determined. This paper also discusses the problems associated with the selection of colours and presents a scheme which uses the CIE 1976 L* u* v* uniform colour space to select 256 colours for replacing the 256 grey shades used to represent the monochrome image.