A digital computer technique for orientation analysis of micrographs of soil fabric

Abstract

SUMMARYSeveral methods exist for quantifying soil fabric information from electron micrographs, but hitherto little interest has been shown in digital computer techniques. This paper describes such a method for the quantitative analysis of the orientation of clay particles in electron micrographs. The intensity distributions across several micrographs have been digitized at up to two million picture points and the data stored on magnetic tape. By examining the gradient of the intensity variations in two orthogonal directions, the resulting intensity gradient vector at each point can be determined. The information from all points in a micrograph can then be plotted as a rosette diagram, or used in a regression analysis to determine the equation of the ellipse which most closely approximates the actual rosette distribution. Finally an index of anisotropy can be estimated from the major and minor axes of the ellipse.