% Sample script for color image segmentation.

% Octave notes:
%  We need the statistics package for kmeans 
%  and we need the image package for the color conversion rgb2lab
%
% If these are not installed, run the following at Octave command line
%   for the image package. (or replace image with statistics if you don't
%   have the statistics package installed).
%
% pkg install -forge image
%
% Uncomment these lines for the first run through Octave
%pkg load statistics
%pkg load image

clear;
clc;

[X,map]=imread('P355F1.jpg');

figure(1)
image(X); colormap(map)

Y=rgb2lab(X);
nrows=size(Y,1); ncols=size(Y,2);

% Strip off "L" channel, just use "a" and "b" channels
Y1=Y(:,:,2:3);

Y2=reshape(Y1,nrows*ncols,2);
[idx,C,disterr]=kmeans(Y2,3);
Z=reshape(idx,nrows,ncols);
figure(2)
imagesc(Z)