Convert RGB colormap to grayscale colormap
Load an indexed image with its colormap into the workspace. The
load command returns a structure containing the image data and the colormap. View the image.
indImage = load('clown.mat'); figure imshow(indImage.X,indImage.map)
Convert the RGB colormap that came with the image into a grayscale colormap.
newmap = cmap2gray(indImage.map);
Display the image with the grayscale colormap.
map— RGB colormap
RGB colormap, specified as a c-by-3 numeric matrix with values in
the range [0, 1]. Each row of
map is a three-element RGB triplet
that specifies the red, green, and blue components of a single color of the
If you have Parallel Computing Toolbox™ installed,
map can also be a
newmap— Grayscale colormap
Grayscale colormap, returned as a c-by-3 numeric matrix with
values in the range [0, 1]. The three columns of
identical, so that each row specifies a single intensity value.
If you have Parallel Computing Toolbox installed, then
newmap can also be a gpuArray.
This function fully supports GPU arrays. For more information, see Run MATLAB Functions on a GPU (Parallel Computing Toolbox).
This function fully supports distributed arrays. For more information, see Run MATLAB Functions with Distributed Arrays (Parallel Computing Toolbox).