circle fitting
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I have a binary image. This image contains white points randomly a ranged inside a region of interest. I want to draw a circle that can include all these points inside it. Means that I want to write a code that detect all these active points automatically and draw a circle in such a way that all the active (white) points come inside this circle. And outer most white point become a part of the boundary of circle. Can anyone help me in that?
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Accepted Answer
Walter Roberson
on 1 Mar 2012
regionprops() the binary image, asking for Centroid and ConvexHull.
The center of the circle will be the centroid.
The ConvexHull will be an N x 2 array of x+y points. The point in that list that is furthest from the centroid will be the point that must be passed through; i.e., that maximum distances will be the radius of the circle.
You could also use the PixelIDList instead of the ConvexHull; it just gives you more points whose distance would have to be calculated.
3 Comments
Image Analyst
on 2 Mar 2012
Then don't accept the answer yet. We don't take personal emails - virtually no one here does. You can post your pictures to tinypic.com, or check here: http://www.mathworks.com/matlabcentral/answers/7924-where-can-i-upload-images-and-files-for-use-on-matlab-answers
More Answers (1)
Image Analyst
on 1 Mar 2012
3 Comments
Image Analyst
on 2 Mar 2012
Neither Walter's nor John's solution will work if you have a random smattering of dots along the top of an arc. In that case you'd have to do a fit. Apparently that's complicated. I have a paper or reference to fitting a circle that I'll try to look up later for you.
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