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

Abstract

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