Deoblique a Neuroimaging Space or Volume

AFNI-like helper that mirrors the core behavior of 3dWarp -deoblique:

• If gridset is supplied, use that as the output grid.

• Otherwise, build an axis-aligned output grid that encloses the input field-of-view.

• If newgrid is not supplied, use the minimum input voxel size isotropically (AFNI-style default for deobliquing).

Usage

deoblique(
  x,
  gridset = NULL,
  newgrid = NULL,
  method = c("linear", "nearest", "cubic"),
  engine = c("internal")
)

Arguments

x

A NeuroSpace or NeuroVol.

gridset

Optional output grid (a NeuroSpace or NeuroVol), analogous to AFNI's -gridset. Mutually exclusive with newgrid.

newgrid

Optional scalar output voxel size (mm), analogous to AFNI's -newgrid. If omitted and gridset is NULL, the minimum input voxel size is used isotropically.

method

Interpolation method used when x is a NeuroVol: one of "nearest", "linear", or "cubic".

engine

Resampling engine passed to resample_to.

Value

If x is a NeuroSpace, returns a deobliqued NeuroSpace. If x is a NeuroVol, returns a resampled NeuroVol in deobliqued space.

Details

For NeuroSpace, this returns the target deobliqued space. For NeuroVol, it also resamples image data into that space.

See also

output_aligned_space, resample_to

Examples

sp <- NeuroSpace(c(32, 32, 20), spacing = c(2, 2, 3))
tx <- trans(sp)
tx[1, 2] <- 0.15
sp_obl <- NeuroSpace(dim(sp), spacing = spacing(sp), trans = tx)

# Build deobliqued target space (minimum spacing default)
sp_deob <- deoblique(sp_obl)

# Resample a volume to deobliqued space
vol <- NeuroVol(array(rnorm(prod(dim(sp_obl))), dim(sp_obl)), sp_obl)
# \donttest{
vol_deob <- deoblique(vol, method = "linear")
# }