Posted by
Dr. Michael DOUBE on
URL: http://imagej.273.s1.nabble.com/Fiji-Drawing-tools-tp5024409p5024415.html
Dear Svenja,
BoneJ's Particle Analyser might do what you want. Click 'Feret Max' which I think is the measurement you describe (maximal distance between two points on the surface). Longest axis can be found a few other ways: e.g. fitted ellipsoid, moments of inertia.
https://imagej.net/BoneJ.html#Particle_Analyserhttps://doi.org/10.1101/2020.02.28.969139BoneJ support is mostly on the forum these days, but we can sometimes be found lurking on the old email list!
Michael
On 27/01/2021 16:45, Straatman, Kees (Dr.) wrote:
Dear Svenja,
Maybe the 3D imageJ Suite (3D ImageJ Suite - ImageJ<
https://imagej.net/3D_ImageJ_Suite><
https://imagej.net/3D_ImageJ_Suite>) can be of use, like Details about 3D ellipsoid fitting [ImageJ Documentation Wiki] (list.lu)<
https://imagejdocu.list.lu/tutorial/plugins/3d_ellipsoid><
https://imagejdocu.list.lu/tutorial/plugins/3d_ellipsoid> or 3D Roi Manager [ImageJ Documentation Wiki] (list.lu)<
https://imagejdocu.list.lu/plugin/stacks/3d_roi_manager/start><
https://imagejdocu.list.lu/plugin/stacks/3d_roi_manager/start>?
Best wishes
Kees
Dr Ir K.R. Straatman FRMS
Advanced Imaging Facility
University of Leicester
www.le.ac.uk/advanced-imaging-facility<
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________________________________
Sent: 26 January 2021 09:03
Subject: Longest axis/minimum containing sphere of 3D object?
Hello everyone!
I have a stack of binary images that is to be interpreted as a 3D image. I have background (in black) and one irregular-shaped object in it (the model of a soil aggregate). I now want to know the longest axis of this object.
I thought the easiest way would be to let a function find the smallest containing sphere and take the diameter. I am aware that in BoneJ, there is a function that allows to find an optimal sphere based on points that are marked by hand. This is, however, not quite what I need and I hope to find a solution without too much manual work, since actually, I have a bit more than one stack. Is anyone aware of a function that can do that?
Another way might be to use the 3D Convex Hull package that can find me the vertices of a convex hull of a 3D object. Does anyone have an idea how to find the largest pair-wise distance between them in ImageJ? Or is this something that's better done with another program?
Any hint is appreciated. Thanks in advance!
All the best,
Svenja
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