How to Segment a object's based on color pixel value ? and how to labelling it ?

How to Segment a object's based on color ?and how to labelling it ? Image dynamic ?

Answer 1

[Image Analyst]

You can use the Color Thresholder on the Apps tab of the tool ribbon. Tell it to export the code. Then you can pass the mask into bwlabel() or bwconncomp().

For the image you've shown, it looks like it was already labeled and passed in to label2rgb() function to produce a pseudocolored image. If not, then tell me how you obtained that image and why you don't have the labeled image for it.

[Selva Karna]

Hi Sir thanks for reply, without Color Thresholder apps, How to labeling image by matlab script ? share any sample code or logic ? auto labelling ? or pixel color based grouping ?

[Image Analyst]

See my File Exchange where I have several demos where I use color segmentation without the color thresholder.

And will you respond to my last paragraph?

[Image Analyst]

You can create a histogram (256x256x256) of colors, then use unique() to get the unique colors. Then use a for loop to find all pixels of each color in an RGB image and assign a labeled image the color index. Something like (untested)

[rows, columns, numColorChannels] = size(rgbImage);
hist3d = zeros(256,256,256);
for col = 1 : columns
    for row = 1 : row
        r = rgbImage(row, column, 1);
        g = rgbImage(row, column, 2);
        b = rgbImage(row, column, 3);
        hist3d(r, g, b) = hist3d(r, g, b) + 1;
    end
end
row = 1;
uniqueColors = zeros(nnz(hist3d), 3);
for r = 0 : 255
    for g = 0 : 255
        for b = 0 : 255
            uniqueColors(row, :) = [r, g, b];
        end
    end
end
% Create labeled image.
labeledImage = zeros(rows, columns);
for row = 1 : size(uniqueColors, 1)
    maskr = rgbImage(:, :, 1) == uniqueColors(row, 1);
    maskg = rgbImage(:, :, 2) == uniqueColors(row, 2);
    maskb = rgbImage(:, :, 3) == uniqueColors(row, 3);
    mask = maskr & maskg & maskb; % Mask of where this RGB color occurs in the image.
    labeledImage(mask) = row;
end
imshow(labeledImage, []);
title('Labeled Image')