Image not generated after separation..?

In this code finally image is not being generate. I have following code... I want to detect Lung cancer.

 % This code reads image , extract the part of lung
% and then dispaly the result.

 %%Read the image data
im=imread('LungSeg_01.png');
im=rgb2gray(im);
[row column]=size(im);
imshow(im)
title('the Original Image')

 %%Get the threshold for segmentation using iteration process
%get the maximun and minimun value of the vector
Gmax=max(max(im));
Gmin=min(min(im));

 %supposing T0 is the threshold
T0=(Gmax+Gmin)/2;

 %mean of both parts,then get the new threshold T1
M0=mean(im(find(im<T0))); 
M1=mean(im(find(im>=T0)));
T1=(M0+M1)/2; 

 %get the appropriate threshold 
%by no more then 5000 loops 
for i=1:5000               %here gives the maximun numbers of trying
    if T1~=T0
        T0=T1;
        M0=mean(im(find(im<T0)));
        M1=mean(im(find(im>=T0)));
        T1=(M0+M1)/2;
    else break
    end
end
thresh=T0

 %%Segmentation
for index=1:row*column
    if im(index)>thresh
        im(index)=0;
    end
end
figure,imshow(im)
title('After Segmentation')

 %make a copy,using to get the position
im0=im;

 %%Extract
%divided the image into 2 parts
%foreground with 1,background with 0
for index=1:row*column
    if im0(index)~=0
        im0(index)=1;
    end
end

 %transform im0 into 'logical',then label
%the part of lung has been labelled with 20

 im0=logical(im0);
im0=bwlabel(im0);

 %display the relational pixel
for i=1:row*column
    if im0(i)~=20                
        im(i)=0;
    end
end
figure,imshow(im)
title('After Extract')

[B.k Sumedha]

Do you get any error?

[Nimisha]

No, didnt getting any error. Just code is run without error. But final image is totally black.

I want to detect Lung cancer.

[Walter Roberson]

What reason do you have to expect that there will definitely be 20 or more different labels?

Answer 1

[drummer]

uHm... Did you try to set a displayrange in your imshow?

I don't know... it should work.

    figure,imshow(im, 'DisplayRange', [])

[Walter Roberson]

[] is the default for imshow(). imagesc() uses the same as imshow(). It is image() that defaults to a different display range.