MATLAB Central Newsreader - find maximum radius of the object

find maximum radius of the object

zahra daffa — Wed, 04 Nov 2009 05:38:01 -0500

Hi all,
I need your help

how to find maximum radius of the object where the object can regular (like circle, rectangle, etc) or irregular object.The radius count from center.

please help me...

regards

Re: find maximum radius of the object

Nasser M. Abbasi — Wed, 04 Nov 2009 08:17:12 -0500

"zahra daffa" <zahra_daffa@yahoo.com> wrote in message
news:hcr3vp$hqg$1@fred.mathworks.com...
> Hi all,
> I need your help
>
> how to find maximum radius of the object where the object can regular
> (like circle, rectangle, etc) or irregular object.The radius count from
> center.
>
> please help me...
>
> regards

Which object are you talking about? You really need to be more clear in
describing what you need help with.

Anything and everything in the universe is an object? what is the context
here?

--Nasser

Re: find maximum radius of the object

ImageAnalyst — Wed, 04 Nov 2009 11:37:21 -0500

Once you have your object binarized, use bwboundaries() to get the
boundary coordinates.

Then use bwconncomp (or bwlabel) and regionprops() to get the
centroid.

Then just get the distance between every boundary point to the
centroid for every object, keeping track of the max distance.

This demo may help:
http://www.mathworks.com/matlabcentral/fileexchange/25157

Re: find maximum radius of the object

John D'Errico — Wed, 04 Nov 2009 12:21:01 -0500

ImageAnalyst <imageanalyst@mailinator.com> wrote in message <bb71b75b-868f-4d33-9f94-0ed1fc156d75@s15g2000yqs.googlegroups.com>...
> Once you have your object binarized, use bwboundaries() to get the
> boundary coordinates.
>
> Then use bwconncomp (or bwlabel) and regionprops() to get the
> centroid.
>
> Then just get the distance between every boundary point to the
> centroid for every object, keeping track of the max distance.
>
> This demo may help:
> http://www.mathworks.com/matlabcentral/fileexchange/25157

Of course, the distance to the centroid may not be
a good measure of the size of an object.

You might use a minimal bounding circle instead.
Identify the points, and then call minboundcircle,
found on the file exchange.

http://www.mathworks.com/matlabcentral/fileexchange/13643

HTH,
John