Colormap for Connected Components in an image

Hello all,

Is there a way I can assign individually different colors to the connected components obtained using bwareafilt() function, labeled in an image? I have tried using colormap() function. But it doesn't work.

Thanks in advance.

Answer 1

[Image Analyst]

Yes. See this snippet from my Image Segmentation Tutorial:

% Let's assign each blob a different color to visually show the user the distinct blobs.
coloredLabels = label2rgb (labeledImage, 'hsv', 'k', 'shuffle'); % pseudo random color labels
% coloredLabels is an RGB image.  We could have applied a colormap instead (but only with R2014b and later)
imshow(coloredLabels);
axis image; % Make sure image is not artificially stretched because of screen's aspect ratio.
caption = sprintf('Pseudo colored labels, from label2rgb().\nBlobs are numbered from top to bottom, then from left to right.');
title(caption, 'FontSize', 20);

[CuriousThinker]

Thank you very much for the response, Image Analyst. I tried with the code snippet you suggested, but again the result is just colored with red and black. The code requires me to find only the 5 largest components, from foreground as well as from background. The labeled objects should have individual colors (even if they all belong to foreground, or background).

[Image Analyst]

Then you're not supplying the labeled image but just the binary image instead. Put this code before the label2rgb() call

% Extract the 5 largest blobs.
binaryImage = bwareafilt(binaryImage, 5);
% Give each blob a unique ID label.
labeledImage = bwlabel(binaryImage);

[CuriousThinker]

Thank you once again, Image Analyst. The method you advised me works. Great. But while it colors the selected labels with different colors, it just colors a corner of them instead of coloring them in full, or at least a good part of them. Could you please advice me which direction to take to improve their performance? Thanks.

[Image Analyst]

I don't see how it could color just a corner of the squares since the square is a solid color throughout. You'll have to share your code for me to fix it.

Answer 2

[CuriousThinker]

Thank you, Image Analyst for your kind reply. Could you please advice me how to share the code privately?

[Image Analyst]

No.

[CuriousThinker]

Sorry, Sir. I just meant if there is a way I can upload, still not shown publicly in the discussion.Thank you very much for the help. If there is no way, please tell me. I will upload my code here.