angGaussSumm: Estimate and Summarize Angular Central Gaussian Distribution...

In TobinH/microTransit: Quantitative Polarized Light Imaging and Analysis Tools

Estimate and Summarize Angular Central Gaussian Distribution for Axial Data

Description

angGaussSumm estimates the angular central Gaussian distribution of 3D axial data using Tyler's (1987) maximum likelihood method.

Usage

angGaussSumm(X, alpha = 0.05, tol = sqrt(.Machine$double.eps))

Arguments

X	An [n,3] matrix of Euclidean coordinates for axial orientations, for general use. angGaussSumm will also parse the orientations from a qPLMtab object referenced by this argument, without requiring specific column addresses.
alpha	Alpha value corresponding to confidence interval 1 - CI. Default is 95% CI.
tol	Tolerance for convergence of iterative algorithm. Default value is the default for the all.equal() function. Increase this value if the function returns an identity matrix for the lambda estimate.

Value

A list with four components:

1. $lambda.matrix: a matrix of lambda values,

2. $lambda.eigval: the eigenvalues of the lambda matrix,

3. $lambda.eigvec: the eigenvectors of the lambda matrix (major orientations of the ACG distribution), and

4. $aCI: angular confidence intervals for first axis in second axis plane (I-II), first axis in third axis plane (I-III), and second axis in third axis plane (II-III), given in both radians and degrees.

References

Tyler, D.E., 1987. Statistical analysis for the angular central Gaussian distribution on the sphere. Biometrika, 74(3): 579 - 589.

See Also

Other qPLM Analysis Functions: centroidCorr(), pullCluster(), pullROI(), pullqPLMSample(), qPLMClust(), qPLMTabulate()

Examples

#oldwd<-getwd()
#setwd(system.file("extdata", package = "microTransit"))
#load("testqPLMtab.R")
testqPLMGauss_tab<-angGaussSumm(testqPLMtab)
save(testqPLMGauss_tab, file = "testqPLMGauss_tab.R")
#setwd(oldwd)

TobinH/microTransit documentation built on Jan. 19, 2024, 5:21 a.m.