get-invariant: Tensor Invariants

In astamm/fdatractography: Functional Data Analysis for Tractography in R

Description

A set of functions calculating orthogonal tensor invariants as suggested in the paper by Ennis, D. B., & Kindlmann, G. (2006). Orthogonal tensor invariants and the analysis of diffusion tensor magnetic resonance images. Magnetic resonance in medicine, 55(1), 136-146.

Usage

get_K1_invariant(x)

get_R2_invariant(x)

get_R3_invariant(x)

Arguments

x	An object of class tensor.

Details

get_K1_invariant computes the trace of the tensor, get_R2_invariant computes the fractional anisotropy of the tensor and get_R3_invariant computes the mode of the tensor.

Value

A scalar giving the desired tensor invariant extracted from the input diffusion tensor.

Examples

DT <- diag(c(1.71e-3, 3e-4, 1e-4))
get_K1_invariant(DT)
get_R2_invariant(DT)
get_R3_invariant(DT)

astamm/fdatractography documentation built on May 12, 2019, 5:37 a.m.