library("rplatypus")
mask <- array(1L, dim = c(10, 10, 4))
mask[3:6, 3:6, 2:3] <- 2L
# 32 voxels of 2 x 2 x 5 mm: 32 * 20 mm^3 = 640 mm^3 = 0.64 ml
mask_volume(mask, spacing = c(2, 2, 5))[1] 0.64How much of a volume a class occupies, in millilitres
Description
A voxel count answers nothing on its own: the same tumour is 4000 voxels on one scanner and 12000 on another, and neither number goes in a report. Multiplied by the volume of a voxel it becomes millilitres, which is comparable between scans, between patients and against whatever the radiologist measured by hand.
Usage
mask_volume(mask, spacing, class = 2L)
Arguments
mask
|
A mask of class indices, as predict() returns - one volume, not a stack.
|
spacing
|
Voxel size in millimetres, length 3. volume_info() reports it; so does the spacing_1/2/3 columns of its output.
|
class
|
Which class to measure, numbered from 1 as the colormap and labels are. Defaults to 2, which is the foreground in a binary segmentation.
|
Value
The volume in millilitres.