- Published: Tuesday, 20 March 2012 00:00
Blob3D and Quant3D are custom designed software developed by the High Resolution X-ray CT Facility at the University of Texas at Austin. Both programs run well on most mid range desktop and laptops.
The following overviews are taken from the UTCT website:
Blob3D is designed for efficient measurement of up to thousands of discrete features (e.g. clasts, mineral grains, porphyroblasts, voids) within a single sample. Blob3D is unique because it gives the program operator primary control over data interpretation and measurement, and all computations are carried out in 3D, rather than individually on a series of 2D slices.
A "blob" is a contiguous set of voxels (3D pixels) that meets some user-defined criteria. Three steps are involved in Blob3D data processing. In the first step, Segment, a set of criteria are defined by the user that defines which voxels belong to the material of interest. The second step, Separate, distinguishes contiguous sets of segmented voxels (i.e. blobs) and allows the operator to divide interconnected or touching objects into individual objects. The third step, Extract, performs measurements on separated objects, such as size, shape, orientation, and contact relationships. Another feature in the Extract module allows the user to input sample coordinates (e.g. strike and dip) and the program calculates geographic coordinates for mineral grains or other features of interest in a sample.
Blob3D is a powerful quantitative tool for CT data and has been applied to the study of a wide variety of problems. Geological examples include textural analysis of porphyroblasts in metamorphic rocks (Ketcham et al., 2005), measurement of vesicles in meteoritic basalts (Benedix et al., 2003; McCoy et al., 2002) and troilite particles in chondritic meteorites (Nettles and McSween, 2006), and grading and orientation analysis of gold grains in ores (Kyle and Ketcham, 2003; Mote et al., 2005). It can also be used for engineering applications, such as quantifying aggregate clasts in asphalt concretes (Ketcham and Shashidhar, 2001) and the pore structure of tissue scaffolds (Dunkers et al., 2005). It can also be used for segmenting and quantifying complex three-dimensional structures such as nasal passageways (Rowe et al., 2005).
Quant3D is a versatile program that can be used to analyze fabrics in any three-dimensional data set; examples include quantification of anisotropy in trabecular bone (Ketcham and Ryan, 2004; Ryan and Ketcham, 2005) and textural analysis of metamorphic rocks (Ketcham, 2005b). Fabric tensors are produced based on the star volume distribution (SVD), star length distribution (SLD), and mean intercept length (MIL) methods. Principal component directions and magnitudes are provided by the tensors, providing the degree of anisotropy and shape indices of the phase of interest. Three-dimensional rose diagrams are a unique feature implemented in Quant3D for analyzing non-orthogonal directional fabric components; they are VRML-format graphics files that can be rotated and viewed interactively.
Ketcham, R.A. (2005b) Three-dimensional textural measurements using high-resolution X-ray computed tomography. Journal of Structural Geology, 27, 1217-1228.
Ketcham, R.A., and Ryan, T. (2004) Quantification and visualization of anisotropy in trabecular bone. Journal of Microscopy, 213, 158-171.