Error with image analysis

Hello!

I've been trying to get this script working, but I don't know how. What it should be able to do is make the image black and white and be able to pick out the centroid of the object in the image.

Image

Code

i = imread('343A #1.tif');
j = size(i);
imtool(i);

for k = 1:j(1)
    for l = 1:j(2)
        if i(k,l,1) > 160 & i(k,l,2) > 160
            d(k,l) = 1;
        else
       d(k,l) = 0;
        end
    end
end
imtool(d);

label = bwlabel(d);
imagesc(label);

[label,num] = bwlabel(d,4);

stats = regionprops(label,'basic');

stats(1).Area
stats(1).Centroid
max_area = max([stats.Area]);
biggrain = find([stats.Area]== max_area);
stats(biggrain).Centroid

Error

??? Attempted to access i(2,51,2); index out of bounds because size(i)=[256,64,1].

Error in ==> TestingCentroid3 at 10 if i(k,l,1) > 160 & i(k,l,2) > 160

[Frank]

I've changed the image format to a tiff file to suit my problem better, however I am still receiving the same error.

Answer 1

[Sean de Wolski]

i is apparently a 2d image. what is j (size(i))?

d = I > 160;  %don't name your variables i,j as they are the sqrt(-1)

[Frank]

j = size(i); % compute the size of the ball

[Sean de Wolski]

I meant what were the values...

Answer 2

[Frank]

Got it.

clc;
close all;

i = imread('343c001.tif');
j = size(i);
imtool(i);

for k = 1:j(1)
    for l = 1:j(2)

          if i(k,l,1) > 160 & i(k,l) > 160  %I removed the 2
              d(k,l) = 1;
          else
         d(k,l,1) = 0;

          end
      end
  end
  imtool(d);

label = bwlabel(d);
imagesc(label);

[label,num] = bwlabel(d,4);

stats = regionprops(label,'basic');

stats(1).Area
stats(1).Centroid
max_area = max([stats.Area]);
biggrain = find([stats.Area]== max_area);
stats(biggrain).Centroid

[Sean de Wolski]

i(k,l,1) is the same location as i(k,l).

hence instead of both for-loops you could do

d = i>160;

[Sean de Wolski]

And I'll repeat: Don't name your variables i,j!