Hallo Philippe,
there is no "smallest rectangle ROI" in an ellipse.
In an ellipse, defined by x*x/a*a + y*y/b*b = 1,
a rectangle is described by A = x*y = sqrt(a*a*x*x - x*x*x*x)*b/a .
A = 0 for x = 0 and for x = a.
The maximum rectangle inside the ellipse is where dA/dx = 0, which is
a*a*x*x - 2*x*x*x = sqrt(a*a*x*x - x*x*x*x) * a/b
So, if you are looking for the maximum rectangle ROI in an ellipse and
if you have the ellipse parameters you can calculate x for dA/dx=0 and
from that the y value.
Hope this helps.
Regards,
Peter
On 24.05.2016 15:46, Philippe CARL wrote:
> Dear all,
>
> Is there an easy way to extract the "smallest rectangle ROI" found within an
> elliptical ROI (i.e. similarly to Edit->Selection->To_bounding_box which
> corresponds to the "biggest rectangle ROI").
>
> I thank you very much in advance for your lightings.
>
> My best regards,,
>
> Philippe
>
>
>
> Philippe CARL
>
> Laboratoire de Biophotonique et Pharmacologie
>
> UMR 7213 CNRS - Université de Strasbourg
>
> Faculté de Pharmacie
>
> 74 route du Rhin
>
> 67401 ILLKIRCH
>
> Tel : +33(0)3 68 85 41 84
>
>
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