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From: trancemissionxxi@gmail.com
Newsgroups: comp.soft-sys.matlab
Subject: Re: Fit sphere to planar circles
Date: Wed, 8 Apr 2009 09:43:06 -0700 (PDT)
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Sven,

For some reason fspecial3 is not showing up on file exchange anymore.
I googled it and the link is:

http://www.mathworks.com/matlabcentral/files/15981/fspecial3.m

I do 3D cell nuclei tracking, which are almost spherical, but I know
about the acetabular issue from papers I read on hough transform
(tried using it before for my problem).

Indeed the fft can become computationally intensive if the image and
mask are large (for me largest volume element is 49x49x49 pixels).
I like your idea on doing the convolution on the hough transformed
circles/disks. Since you are done with using the grayscale and have
binary data for the slice circles, why not resize the image and do
convolution on smaller image size (if large matrices are a problem).
Alternatively, you can use a scanning box algorithm on your new voxel
volume with detected disks.

There's also this paper (not sure if you have access):
http://dx.doi.org/10.1016/j.patrec.2005.11.019

Cheers.