espadon (version 1.11.3)

fan.planar: Creation of pyramid fan object passing through pixels of a plane.

Description

The fan.planar 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 passing through all pixels of a plane, which represent the pyramid basis. It is for instance useful to compute rt-image.

Usage

fan.planar(
  vol,
  k = vol$k.idx[ceiling(length(vol$k.idx)/2)],
  origin = c(0, 0, 0),
  alias = "",
  description = "planar fan"
)

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.coords : a list of the ijkt DICOM coordinates of the crossed plane, and the transfer matrix to xyz.from.ijk to compute xyz coordinates in $ref.pseudo.

Arguments

vol

"volume" class object.

k

Positive number specifying the plane index that the rays of the fan must cross. By default, k is the central plane.

origin

Numeric vector, giving the xyz coordinates of the fan origin. By default c (0, 0, 0).

alias

Character string, $alias of the created object.

description

Character string, describing the the created object.

See Also

fan.sphere, fan.beam, fan.to.voxel

Examples

# loading of toy-patient objects (decrease dxyz and increase beam.nb for
# better result)
step <- 5
patient <- toy.load.patient (modality = c("ct"), dxyz = rep (step, 3))
fan <- fan.planar (patient$ct[[1]], origin = patient$ct[[1]]$xyz0[1,])
head (fan$xyz)
if (interactive()) {
  rgl::open3d ()
  points3d (fan$xyz)
}