How to identify the disk edge?

How can MATLAB determine the radius of the disk? (imagine the center is known)

I know that if the whole circle is visible, I can use imfindcircle or other methods to determine the center and radius, but I wonder whether MATLAB can determine the edge of the radius for such an image?

Thanks

Steven

Answer 1

[Image Analyst]

Try it and see. Otherwise, just segment it and get the edge coordinates with bwboundaries() and use the FAQ to fit them to a circle or ellipse.

[Steven]

Thanks.

How to get the edge using bwboundaries?

Thanks

Steven

[Image Analyst]

First segment based on threshold

binaryImage = grayImage < 128; % or whatever value works.

Then get rid of small noise particles

binaryImage = bwareaopen(binaryImage, 10000);

Then call bwboundaries

boundaries = bwboundaries(binaryimage);

Then do the fit as per the FAQ.