Module: Degree Of Anisotropy ()

Description:

For an introduction, see section Porosity.

This module computes a measure of 3D anisotropy in a binary image. It is a good indicator to detect structural alignments along particular directional axis. The measure is based on an eigen value analysis of the mean intercept length at different angles.

Mean intercept length proceeds by sending a set of oriented ray through the binary image. A set of discreet angles are processed as described and for each one an averaged is done by using a regularly spaced grid of rays. The parameter is the distance between two lines intercept. The pitch angle is fixed at 10 degrees. For each orientation, a regularly spaced grid of rays are shot. The length of the intersection of each ray with the object encountered is measured, and averaged over the grid of rays. The spacing of this grid is controlled by the parameter Intercept Distance.

The distribution of the mean intercept length, as a function of the angle, is analysed via an eigenvalue decomposition. This analysis allows one to extract a minimal and a maximal eigen value. The closest these values are, the less the structural anisotropy is. Indeed maximum and minimum eigen values equality means that their is no privileged structural direction.



Degree Of Anisotropy is 0 for perfect isotropy and 1 for complete anisotropy.

See also: Structure Model Index, Fractal Dimension, Eccentricity, ASBMR Porosity

Connections:

Input Binary Image [required]
The image to be analyzed. Supported types include: binary images (Uniform Label Field with 2 labels).

Ports:

Interpretation

This port specifies whether the input will be interpreted as a 3D volume or a stack of 2D images for processing.

Intercept Distance

Intercept Distance is the distance between two lines intercept.