Computational methods for quantitative analysis of three-dimensional features in geological specimens

Volumetric imaging techniques, such as high-resolution X-ray computed tomography, allow three-dimensional measurements of discrete objects inside solid samples. This paper introduces a new computer program called BLOB3D that is designed to allow efficient measurement of up to thousands of features in a single sample, such as porphyroblasts, sediment grains, clasts, and voids. BLOB3D implements an original suite of software methods, divided into three modules, which respectively enable the tasks of segmenting those regions in the data volume that correspond to the material of interest; separating touching or impinging objects; and extracting measurements from the interpreted volume. Program functions are demonstrated and verified with a set of phantoms used to test determinations of particle size distributions and particle-particle contact orientations.