MATLAB: How to alterate a mask for Kmeans segmentation

Question

Dear all,

For K-means segmentation I used this code:

K = 4; % cluster number
men = menu('Choose the region of analysis','ALL image','Bounding box');
%%
[fname path]=uigetfile('*.*','Enter and Image'); 
fname=strcat(path, fname); 
im=imread(fname); 
 figure, imshow(im)
%% ROI
if men==1
    rect=[1,1,size(im,2)-1,size(im,1)-1];
elseif men==2
    figure(),imshow(im)
    rect = ceil(getrect());
    close
end
% Mask
M = false(size(im(:,:,1)));
M(rect(2):rect(2)+rect(4),...
    rect(1):rect(1)+rect(3)) = true;  
%% function
[L,C_RGB] = kmeansfcn(im,K,M); 
hold on;
figure('Position',[168,182,1625,744])
subplot(2,1,1),imshow(im)
title('Imagine originala')
% legend
leg = {}; hold on
for i=1:K
Col = (C_RGB(i,:)./255);
leg(i,:)={['Cluster ',num2str(i)]};
plot(1,1,'LineWidth',12,'Color',Col)
end
legend(leg,'FontSize',12);hold off 
L=L(1:4:end, 1:4:end,:); % subsampling-iau din 4 in 4 pixeli=> micsorez aria de 4 ori
subplot(2,1,2),imshow(L,[])
title('Segmentare pe clustere') 

with this function:

function [L,C_RGB] = kmeansfcn(img,K, mask)
if length(size(img))==3
    X = [reshape(img(:,:,1),[],1),...
        reshape(img(:,:,2),[],1),...
        reshape(img(:,:,3),[],1)];
else
    X = reshape(img(:,:,1),[],1);
end
mask = reshape(mask,[],1); 
X2 = X(mask,:);
[Clust,C] = kmeans(double(X2),K,'Replicates',6); 
 
C_RGB = round(C);                                  
idx =uint8(mask);              
idx2 = find(idx);
for i=1:length(idx2)
    idx(idx2(i)) = Clust(i);
end
 L= reshape(idx,size(img,1),size(img,2)); 
 

The code works just fine on sole images, but now I want to run it on an image database and I don't need anymore the whole ROI and the menu thing BUT I don't know how change the mask in the main code.

M = false(size(im(:,:,1)));
M(rect(2):rect(2)+rect(4),...
    rect(1):rect(1)+rect(3)) = true;

I understand that this is related to the first part where I draw a rectangle over the region of interest but I can't see how to eliminate that first part without affecting the rest of my code.

Thanks in advance!!

LATER EDIT: I wish to use the full image option for all images, not the bounding box one.

Answer 1

M = true(size(im,1), size(im,2));