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Re: Feret's dimeter

Posted by Michael Schmid on Jan 09, 2015; 2:13pm
URL: http://imagej.273.s1.nabble.com/Feret-s-dimeter-tp5011144p5011154.html

Hi Slobodan,

for the Feret calculation the *corner points* of the selection are taken as points with zero size.  'Corner points' are the points of the outline that define the polygon of the selection.

Selections that are not polygons (splined polygons, ovals) are converted to polygons (using the same method as if you press 'f' for 'fill', and then taking the outline). This causes a notable error for small ovals and circles.


If you select a single pixel, the selection is a small square with four corner points and a side length of 1.  So you get minFeret=1 and maxFeret=sqrt(2).

Michael
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On Jan 9, 2015, at 12:04, Slobodan Dražić wrote:

> Hi Michael,
>
> thanks for code and explanation.
>
> I looked through the code. Sorry for asking too much, I am not familiar with Java. As much as I understand it observes pixel as a point with integer coordinates. Does not consider it as  a Voronoi region (whole square). It does not take into account the whole pixel when estimates diameter. I am not sure what you meant by "any two corner points"? Corner points of all the pixels?
>
> Slobodan
>
>
>
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