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checkSpheres

checkSpheres performs a sanity check on the multisphere head models produced by the localSpheres program. It will report average sphere centers and radii, and also includes a distance check that works based on the assumption that most of the spheres should contain the centers of most of the other spheres. If you get warnings from this program, consider recalculating the multisphere model either by fixing the headshape, or specifying a larger radius to the localSpheres program (-r).

Download and Installation

An x86 binary is located here: checkSpheres. Just copy it to your bin directory and make it executable. The source code is here.

Usage

Please note that the warnings that this program produces are merely informative. The thresholds were determined emperically and don't reflect a careful analysis of what actually constitutes a good model. The point here is to avoid extremely large values. Most of the spheres should be near the surface of the head. Note that if you used a brainshape, instead of a headshape, you should expect a tighter grouping.

The biggest problems are with the relatively flat sides of the head, which can produce very large, off-center spheres. Also, noise in the MRI can produce total garbage.