darkpix: Calculates percentage of dark pixels in an image.

In ozjimbob/ecbtools: Environmental Change Biology Tools

Description

This function takes a colour image file, typically a JPEG, and counts the percentage of pixels below a certain darkness threshold. By default, only a central circle representing the hemispherical horizon is counted. The threshold at which darkness is detected can be altered.

Usage

darkpix(file, cutoff = 100, clip.circle = T)

Arguments

file	Character string for the filename of the image file to be processed.
cutoff	The cutoff value, from 0-255. Pixels with brighness values below this threshold are considered dark.
clip.circle	True/fale - if true, central circle of image is used. If false, whole image is used.

Value

A value representing the percentage of dark pixels in the image.

Author(s)

Grant Williamson <[e-mail]>

See Also

darkpix.dir

Examples

rlogo=system.file("pictures/Rlogo.jpg", package="rgdal")[1]
darkpix(rlogo,cutoff=100,clip.circle=T)

ozjimbob/ecbtools documentation built on Jan. 18, 2021, 7:39 p.m.