Construct a mean image, blur and threshold to make an ROI for analysis

make_roi_from_mean(x, blur = 5, thr = "95%", ...)

Arguments

x	A hyperstack or path to one or more TIFF files (see `make_hyperstack`)
blur	The gaussian sigma to use
thr	A thresholding specification (passed to `imager::threshold`)
...	Additional arguments passed to `make_hyperstack`

A 2D mask in the form of an imager::cimg object

This is currently targeted at single plane imaging data.