Expand meshes keeping the center of gravity, ImageJ

Hi experts
I have searched for a while for a way to expand 3D objects, keeping the shape and center of gravity and finally kind of gave up/realized my lack of ingenuity and posted it here. I need to create an expanded 3D mask from one channel to measure the amount of signal in another. I tried normal dilations but these deform completely the shapes in 3D making everything round. There is an option to keep the shape when expanding, but this only works in 2D. I thought of getting the meshes for the 3D masks with the centers of gravity for each object and although I don’t know how to do this, I beforehand have realized that it exceeds my current skills. Asked around but got no great solutions. Anyone? (Thanks in advance!)


Happy first forum post!

It sounds like what you want is to apply a spatial transformation to your mask (not to apply a pixel-wise operation to it).

Example, scale this funny shape by a factor of 1.5 about its center,
left is original, right is scaled:


Here’s a script that will compute the center of mass of your mask, and scale it about its center:

Save it to your computer, open with fiji, and hit run. Learn more about scripting here

Let me know if you have any questions,

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Wow! Thanks - it looks exactly as the solution I looked for! I’ll try it and let you know if I have problems.

Best, Thomas

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