How can a greyscale image be labeled?

How can a greyscale image be labeled?

As bwlabel() works for labeling binary image how can we do the same for greyscale image in matlab

[Image Analyst]

What's the use case? Why do you want this? What are you going to do with it? Can you give an example of the output you want for a small 7 by 7 image like this:

grayLevelImage =
     1     1     2     4     5     5     1
     5     4     1     3     2     1     5
     3     2     1     3     2     1     4
     5     1     1     3     3     1     4
     2     3     4     1     4     1     1
     3     1     2     3     3     4     5
     4     1     3     5     2     3     5

[Sheema Khattak]

I need to label the segmented portions of image for identification.No not small one

Answer 1

[Walter Roberson]

labelled_image = zeros(size(YourImage),'uint16');

label_hw = 0;
max_grey = max(YourImage(:));
for K = 1 : max_grey
  T = bwlabel(YourImage == K);
  numlabel_here = max(T(:));
  for L = 1 : numlabel_here
    labelled_image(T == L) = label_hw + L;
  end
  label_hw = label_hw + numlabel_here;
end

At the end of this, labelled_image will be labelled such that each connected area that is all a single greyscale level will be considered to be a single class.

This is unlikely to be what you want: you probably want that "nearby" greyscale levels are merged together but that "edges" are recognized. That kind of separation is what segmenting is for.