How to convert RGB image to CIELAB using raster package in R?

Question

I have read an RGB image using the following code

library(raster)
#Load an image
logo <- stack(system.file("external/rlogo.grd", package="raster"))
plot(logo)

Now, I want to convert the RGB image to CIELAB image. How to do it using raster R package? I know CRImage Bioconductor package has a function to implement this (convertRGBToLAB). But I want to implement it using raster R package.

score 2 · Accepted Answer · answered May 14 '21 at 08:48

2

You could use the convertColor() function:

library(raster)
logo <- stack(system.file("external/rlogo.grd", package="raster"))
plot(logo)

new_vals <- values(logo) / 255
new_vals <- convertColor(new_vals, from = "sRGB", to = "Lab")
values(logo) <- new_vals
plot(logo)

answered May 14 '21 at 08:48

Jot eN

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I want to have average values of Lab. How to do that? – UseR10085 May 14 '21 at 13:42
or like this: `x <- calc(logo, function(i) convertColor(i, "sRGB", "Lab", scale.in=255))`. Perhaps followed by `mean(x)`, to get the average – Robert Hijmans May 14 '21 at 14:48
@RobertHijmans `x <- calc(logo, function(i) convertColor(i, "sRGB", "Lab", scale.in=255))` is taking long time to do the job. – UseR10085 May 15 '21 at 04:40

How to convert RGB image to CIELAB using raster package in R?

1 Answers1