Determines optimal scaling constant for a list of CIs

Usage

autoscale(cis, save_as_pngs = TRUE, targetpath)

Arguments

cis: List of cis, each of which are a list containing the pixel matrices of at least the noise pattern ($ci) and if the noise patterns need to be written to PNGs, also the base image ($base).
save_as_pngs: Boolean, when set to true, the autoscaled noise patterns will be combined with their respective base images and saved as PNGs (using the key of the list as name).
targetpath: String specifying the directory to save PNGs to. Required when save_as_pngs = TRUE; there is no default path. It is created if it does not exist. Use tempdir() if you only want to try the function out.

Value

The input cis list, with the $scaled pixel matrix of each element replaced by its autoscaled version. The scaling constant that was determined is printed to the console, not returned.

Look at $scaled, not $combined. $combined is left exactly as it was passed in: autoscaling deliberately does not disturb it, so a combination made before this call survives unchanged. Only $scaled reflects the autoscaled result. If you want the autoscaled noise shown over the base image, build it yourself with (ci$scaled + ci$base) / 2 — that is exactly what save_as_pngs = TRUE writes to disk.

This matters most after batchGenerateCI or batchGenerateCI2IFC, which scale with 'none' before handing over to this function: their $combined is therefore an overlay of the unscaled noise and will look almost blank, while $scaled is the image you want.

Examples

cis <- list(
  participant1 = list(ci = matrix(runif(64, -0.2, 0.2), 8, 8), base = matrix(0.5, 8, 8)),
  participant2 = list(ci = matrix(runif(64, -0.3, 0.3), 8, 8), base = matrix(0.5, 8, 8))
)
scaled_cis <- autoscale(cis, save_as_pngs = FALSE)
#> Using scaling factor constant:0.298241481184959