library("rplatypus")
coloured <- classes_to_colours(matrix(c(1, 2, 2, 1), nrow = 2), binary_colormap)
colours_to_classes(coloured, binary_colormap)$classes [,1] [,2]
[1,] 1 2
[2,] 2 1Read a colour mask back to class indices
Description
The inverse of classes_to_colours(). Anything matching no colour becomes background, and coverage in the result says how much of the mask that was - a number near 1 means the colormap does not describe this dataset, which is the quietest way to train on nothing.
Usage
colours_to_classes(mask, colormap, tolerance = 0)
Arguments
mask
|
An RGB array: height x width x 3, or with a leading image axis.
|
colormap
|
A list of RGB triples, one per class. |
tolerance
|
Allow this much difference per channel. Useful after lossy resizing, though masks should be resized with nearest = TRUE so it is not needed.
|
Value
A list with classes (indices counted from 1) and coverage (the fraction of pixels that matched a colour).