imager (version 0.45.8)

grayscale: Convert an RGB image to grayscale

Description

This function converts from RGB images to grayscale

Usage

grayscale(im, method = "Luma", drop = TRUE)

Value

a grayscale image (spectrum == 1)

Arguments

im

an RGB image

method

either "Luma", in which case a linear approximation to luminance is used, or "XYZ", in which case the image is assumed to be in sRGB color space and CIE luminance is used.

drop

if TRUE returns an image with a single channel, otherwise keep the three channels (default TRUE)

Examples

cimg.limit.openmp()
grayscale(boats) %>% plot
#In many pictures, the difference between Luma and XYZ conversion is subtle 
grayscale(boats,method="XYZ") %>% plot
grayscale(boats,method="XYZ",drop=FALSE) %>% dim