MATLAB: Comparing volume of two 3d matrices

Question

I have two 3d matrices called ORIGINAL and RECONSTRUCTED, size 500x500x500.

• ORIGINAL [Solid intensity: 0 black , 1 white]
• RECONSTRUCTED [intensity: 0 black to 1 white]

each matrix contain an object that can be viewed using command : isosurface(Volum,0.5);

How can I compare the size of those two object in Matlab?

Is there a way to combine the two matrix together and draw an isosurface of the two Objects after combination?

Thanks

Answer 1

If the objects are convex then you can use the second output of convhulln to give you the volume directly. If not, then you have a few options:

You can just sum the images:

v1 = sum(sum(sum(original)));
v2 = sum(sum(sum(original)));

You could use a more fancy approach such as this:

FEX:mesh2tetra

And there are other ways.

For my masters thesis that did quite a bit of CT volume analysis, I just summed - it was a good enough approximation and there were many other attributes in the image that cause more error than this (reconstruction/downsampling bits/binarizing/noise, etc).