In Ilastik, are radii of the object scaled differently than pixels?

I am trying to obtain the length and width of objects in Ilastik. I assume that the radii of object (0 and 1) could be used to calculate the area of the bounding ellipse. However, if I do this, I find that the ellipse is predicted to have approximately 1/10 the area of the object. Is the bounding ellipse scaled differently than to pixels? Is it scaled to 1/10 the area in pixels?


Hi @Lee_DeHaan,

the radii of the object are the eigentvalues of the PCA of the coordinates. So those give you the radii (roughly) of an ellipse fit to the pixel coordinates that compose the objects. It is not meant to be enclosing.
Otherwise there is no additional scaling. Radii are given in units of pixels.


Hi k-dominik
Please help me with the problem.
In the test image, I drew a circle with a radius of 100 pixels. After classifying the objects, I determined that the radii of the ellipse are 50 pixels. It is known that a circle is an ellipse with semiaxes equal to each other. 50 is less than 100 in half.
The rest of the objects in the test picture also have “underestimated” values of the ellipse radii.
How can this be?
Sorry, I use google translator. Thank you!