dd_rice

3D-Rice distribution

Syntax

info = dd_rice()
P = dd_rice(r,param)
Parameters
  • r - Distance axis (N-array)
  • param - Model parameters
Returns
  • P - Distance distribution (N-array)
  • info - Model information (struct)

Model

P(r) = \frac{\nu^{n/2-1}}{\sigma^2}r^{n/2}\exp\left(-\frac{(r^2+\nu^2)}{2\sigma^2}\right)I_{n/2-1}\left(\frac{r\nu}{\sigma^2} \right)

where n=3 and I_{n/2-1}(x) is the modified Bessel function of the first kind with order n/2-1. This is a three-dimensional non-central chi distribution, the 3D generalization of the 2D Rice distribution.

Variable Symbol Default Lower bound Upper bound Description
param(1) \nu 3.5 1.0 10 Center
param(2) \sigma 0.7 0.1 5 Width

Example using default parameters:

../_images/model_dd_rice.png

Description

info = dd_rice()

Returns an info structure containing the specifics of the model:

  • info.model - Full name of the parametric model.
  • info.nparam - Total number of adjustable parameters.
  • info.parameters - Structure array with information on individual parameters.
P = dd_rice(r,param)

Computes the distance distribution model P from the axis r according to the parameters array param. The required parameters can also be found in the info structure.