20 Oct
2006
20 Oct
'06
9:18 a.m.
Hello all,
I'm interested in correcting the geometric distortion introduced by the non-linearity of the gradients of our Sonata MR system. I noticed that mri_convert has an option to do this: --unwarp_gradient_nonlinearity
When I try to use this option, I get an error message: INFO: unwarping ... Error: couldn't open /usr/local/bin/freesurfer/data/gradientNonlinearitySonata.mff
So this file seems to be missing in the freesurfer distribution. Can I request that file somewhere, or is any software available to calculate it from the spherical harmonics as provided by Siemens?
cheers -- Joost