[Insight-users] Circularity and Compactness Measure

[José Santamaría López]

Yes, you are right. It depends on the nature
of images you deal with.

Regards.


Andinet Enquobahrie
> José Santamaría López wrote:
>
>>Perhaps, what I am going to say could be
>>trivial, but may help you:
>>
>>
>>The radius of the largest possible circle can be
>>computed by the distance between the center of
>>mass of the segmented image and the furthest point
>>at the segmented one.
>>
>>
> Just as a caveat.....
>
> This suggestion might not work for all types of segmented regions.  For
> some geometrical shapes,
> the center of mass might be outside  the segmented image (For example,
> ring or irregular and convoluated shaped objects)
>
> -Andinet
>
>
>
>>And, the smallest possible radious that will enclose
>>it can be computed by the distance between the center of
>>mass and its closest point on the segmented image.
>>
>>This could be an ill scheme for solving your
>>requeriments, mainly when the noise is a relevant
>>factor present in the images you are using. You can
>>make use of a more robust mechanism, for instance,
>>take a median value for each one of the rules.
>>
>>I don't know whether it is implemented in ITK, but
>>some components of it could help you, for instance
>>a Kd-Tree to compute the closest point rule.
>>
>>Regards.
>>
>>Karthik Krishnan
>>
>>
>>>On Sun, 2006-04-02 at 19:25 -0500, Matt Kelsey wrote:
>>>
>>>
>>>>Hello All,
>>>>I need to measure the circularity and compactness of a 2D segmented
>>>>object. To do so, I'd like to compute the radius of the largest
>>>> possible
>>>>circle that will fit in the shape and the smallest possible that will
>>>>enclose it. Does anyone know of a built-in ITK function that will do
>>>>this?
>>>>
>>>>
>>>The largest medial radius is the smallest possible circle that encloses
>>>your segmentation.
>>>
>>>The filter:
>>>http://www.itk.org/Insight/Doxygen/html/classitk_1_1BinaryThinningImageFilter.html
>>>will find the skeleton of your 2D shape.
>>>
>>>The largest binary ball when centered on the skeletal pixels that has
>>>all pixels inside it "on" is the largest medial radius.
>>>
>>>
>>>
>>>I have no knowledge of algorithms that compute the circumcircle of an
>>>arbitrary shape, but it seems to me that you can approximate that
>>>computing the largest image extents along the x/y axis by rotating it
>>>from 1 through 90 degrees in steps of 1.
>>>
>>>-karthik
>>>
>>>
>>>
>>>>Thanks for any ideas,
>>>>Matt
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>>>>
>>>>
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>>
>>
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