MATLAB: How to cluster a binary image

image processingImage Processing Toolboximage segmentation

I have the following image. Now I want to separate the black and white pixel from the image so that I can fit an ellipse to each black pixel area and find the length of the major axis of each ellipse. How can I separate black pixel from the white pixel and fit an ellipse?

Best Answer

See my image processing tutorial: http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862

Basically, here are the steps.

% Invert your image so the black things are white.
binaryImage = grayImage < 128;
% Call bwlabel
[labeledImage, numberOfRegions] = bwlabel(binaryImage);
% Call regionprops
props = regionprops(labeledImage, 'MajorAxisLength', 'Orientation');

It's all shown in Steve's blog:

http://blogs.mathworks.com/steve/2010/07/30/visualizing-regionprops-ellipse-measurements/

Related Solutions

MATLAB: How can i separate all the connected regions in a binary image and display them individually.

Use bwlabel() and ismember

[labeledImage, numRegions] = bwlabel(binaryImage);
props = regionprops(labeledImage, 'Area')
% Compute all the areas.
allAreas = [props.Area]
% Display each blob in its own figure.
for k = 1 : numRegions
    thisRegion = ismember(labeledImage, k);
    figure;
    imshow(thisRegion);
    drawnow;
end

MATLAB: How to select an object of a bw image

With regionprops():

labeledImage = bwlabel(binaryImage);
measurements = regionprops(labeledImage, 'Area');
allAreas = [measurements.Area]

See my Image Segmentation Tutorial for a full demo: http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862

Best Answer

Related Solutions

MATLAB: How can i separate all the connected regions in a binary image and display them individually.

MATLAB: How to select an object of a bw image

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