K-Nearest Neighbors for image segmentation

Script Exemple :
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% k of k-nearest neighbors
k = 3 ;
% generate a test image data , a matrix of 3 by 3, values are doubles that
% range from 10 to 20
im_test_data = [10 20 30; 20 10 30; 20 10 30];

% generate a training/apprentissage data image from test data image
im_tr_data = [10 0 30;0 10 0; 20 0 30];

% generate a truth image labels with 3 by 3 matrix, values are integers
% that range from 1 to 3 (10 correspond to label 1, 20 to 2 and 30 to 3)
im_t_lbls = [1 2 3; 2 1 3; 2 1 3];

% generate a training/apprentissage image labels from truth image labels
im_tr_lbls = [1 0 3;0 1 0; 2 0 3];

% we are looking for "test_lbls" ?
test_lbls = knnAlgo(im_test_data, im_tr_data,im_tr_lbls,k);