fan.beam: Creation of pyramid fan object with constant angle step.

In espadon: Easy Study of Patient DICOM Data in Oncology

Creation of pyramid fan object with constant angle step.

Description

The fan.beam function creates a "fan" class object containing, among others, the coordinates of the unit director vectors of the rays of rectangular pyramid fan. Rays are uniformly distributed by angle.

Usage

fan.beam(
  alpha,
  dalpha,
  orientation = c(0, 0, 1, 1, 0, 0),
  origin = c(0, 0, 0),
  ref.pseudo = "ref1",
  frame.of.reference = "",
  alias = "",
  description = "beam fan"
)

Arguments

alpha	Positive number specifying the half-angle of the conical beam.
dalpha	Positive number specifying the step of the angle between the rays of the cone beam.
orientation	Vector orientation of the pyramid base composed by the 2 orthonormal vectors coordinates.
origin	Numeric vector, giving the xyz coordinates of the fan origin. By default c (0, 0, 0).
ref.pseudo	Character string, frame of reference pseudonym of the created object.
frame.of.reference	Character string, frame of reference of the created object.
alias	Character string, $alias of the created object.
description	Character string, describing the the created object.

Value

Returns a "fan" class object (see espadon.class for class definitions) containing, among others,

• $xyz : a matrix of 3 columns giving the xyz coordinates of the fan rays.

• $local : a matrix of 2 columns indicating the deflection angle (in rad) in the main directions defined by orientation.

See Also

fan.planar, fan.sphere, fan.to.voxel.

Examples

fan <- fan.beam (alpha = 30, dalpha = 1)
head (fan$xyz)
if (interactive()) {
  rgl::open3d ()
  rgl::points3d (fan$xyz)
}

espadon documentation built on April 11, 2025, 5:57 p.m.