Coerce a streamline or bundle to a dwiFiber object

as_dwifiber() converts a streamline or bundle to the S4 class dwiFiber from the dti package.

Usage

as_dwifiber(x, ...)

Arguments

x

A streamline or bundle object.

...

Additional arguments (currently unused).

Value

An S4 object of class dwiFiber (from dti).

Details

Per-point direction vectors are taken from @point_data$direction_x, @point_data$direction_y, and @point_data$direction_z when present; otherwise they are estimated via finite differences of the coordinates (forward difference at the first point, backward difference at the last, central differences in between), then unit-normalised.

Bundle-level metadata stored in @bundle_data under the keys method, minfa, maxangle, ddim, ddim0, voxelext, orientation, rotation, level, and source are transferred to the corresponding dwiFiber / dwi slots when present. MRI-acquisition metadata that cannot be recovered from a fiber object (gradient directions, b-values, etc.) are filled with neutral placeholders.

See also

as_streamline(), as_bundle()

Examples

if (requireNamespace("dti", quietly = TRUE)) {
  pts <- matrix(runif(15), ncol = 3, dimnames = list(NULL, c("X", "Y", "Z")))
  sl  <- streamline(points = pts)
  b   <- bundle(streamlines = list(sl))
  dfi <- as_dwifiber(b)
  class(dfi)  # "dwiFiber"
}
#> Warning: RGL: unable to open X11 display
#> Warning: 'rgl.init' failed, will use the null device.
#> See '?rgl.useNULL' for ways to avoid this warning.
#> [1] "dwiFiber"
#> attr(,"package")
#> [1] "dti"