rgb2grey: Convert RGB to greyscale using 'average' or 'gleam' methods

In treysp/coolit: Identify water cooling towers from aerial orthoimagery

Description

Convert RGB to greyscale using 'average' or 'gleam' methods

Usage

rgb2grey(my_brick, method = c("ave", "gleam"))

Arguments

my_brick	Object of class RasterBrick or RasterStack from the raster package
method	Method of converting RGB to greyscale

Details

For the 'gleam' method we assume that the RGB image has been gamma-compressed. We then: 1. Gamma expand it based on the formula at the wikipedia link below 2. Calculate the arithmetic mean across the gamma-expanded channels 3. Rescale to 0:255

See PLoS One article referenced below.

References

https://en.wikipedia.org/wiki/Grayscale#Converting_color_to_grayscale https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0029740

treysp/coolit documentation built on June 5, 2019, 5:16 p.m.