MATLAB: How to get a crop a circluar region

crop

i wanted to crop a circular region as shown
please can someone help me….
to get the output (a) i used the below code in link
 http://stackoverflow.com/questions/19992097/how-to-do-circular-crop-using-matlab
I = imread('patricia.jpg');
imageSize = size(I);
ci = [250, 300, 100];     % center and radius of circle ([c_row, c_col, r])
[xx,yy] = ndgrid((1:imageSize(1))-ci(1),(1:imageSize(2))-ci(2));
mask = uint8((xx.^2 + yy.^2)<ci(3)^2);
croppedImage = uint8(zeros(size(I)));
croppedImage(:,:,1) = I(:,:,1).*mask;
croppedImage(:,:,2) = I(:,:,2).*mask;
croppedImage(:,:,3) = I(:,:,3).*mask;
imshow(croppedImage);
but the cropping is not coming correctly…. if i binarize and use regionprops the circle is being distorted… please do help

Best Answer

If the circle is displaying as an ellipse then you need to give the command
axis image
or do the equivalent (axes DataAspect property)
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