how can i convert RGB image to indexed image without using toolbox?

i want to convert rgb image to indexed image but without using toolbox, with colormap and impixel

Answer 1

[Guillaume]

Since rgb2ind is part of base matlab, you can use that. No toolbox required.

[maha D]

i tried to do it but it's showing any thing

Answer 2

[Image Analyst]

rgb2ind() doesn't work? Really? Then please read this link, then post your code.

In the meantime, this works just fine for me:

rgbImage = imread('peppers.png');
subplot(2, 1, 1);
imshow(rgbImage); % Show original image
[indexedImage, map] = rgb2ind(rgbImage, 8);
subplot(2, 1, 2);
imshow(indexedImage, map); % Show posterized version
colorbar;

Since you forgot to share your code, can you run my code and verify that rgb2ind() still does not work for you? Then, since it works for me and I can't reproduce your system's behaviour, and does not work for you, you should call the Mathworks for tech support.

[maha D]

function [ind, map] = myrgb2ind(rgb);
rgb = imread('rgb.TIF');
[ind,map] = rgb2ind(rgb,8);
impixel(ind);
imagesc(ind);
colormap(map);
imshow(ind);
end

%this is my code i don't know what is wrong with it.

[Image Analyst]

You don't need to call both imagesc() and imshow(). Just call imshow(). And call colormap AFTER you call imshow().

And you don't need to call impixel() at all. If you want to see what the values are, just use impixelinfo().

Look at my code. Just do it like that, not the way you did it.