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Hi Moo, I actually implemented your diffusion smoother but could not quite get it to work. It might have been related to the delta t parameter. Can you give some guidance as to how to set it? What's the difference between heat kernel smoothing and diffusion smoothing? btw, the link to the "Diffusion smoothing on cortex" software on your web page is broken. thanks doug
Moo K. Chung wrote: Dear Dr. Park, I guess you are asking about freesurfer related surface smoothing. Although I am not exactly sure how FreeSurfer is implmenting surface smoothing, the general theory of suface-based smoothing and FWHM can be found in two of my previous publications:Chung, M.K., Worsley, K.J. , Paus, T., Cherif, C., Giedd, J.N., Rapoport, J.L, Evans, A.C. 2001. A Unified Statistical Approach to Deformation-Based Morphometry, NeuroImage 14:595-606. http://www.math.mcgill.ca/chung/deformation/ni_deformation.pdf Chung, M.K., Robbins,S., Dalton, K.M., Davidson, Alexander, A.L., R.J., Evans, A.C. 2005. Cortical thickness analysis in autism via heat kernel smoothing. NeuroImage 25:1256-1265. http://www.stat.wisc.edu/~mchung/papers/ni_heatkernel.pdf These softwares implemented in MATLAB can be found in my webpage http://www.stat.wisc.edu/~mchung/softwares/sotfwares.html for other type of triangular meshes. Moo. On 6/27/05, Hae-Jeong Park, PhD <[EMAIL PROTECTED]> wrote:Hi, I would like to know the relationship between number of iteration in surface smoothing and Gaussian kernel size in FWHM. Would you give me some information on this? Thank you in advance. Hae-Jeong -- Hae-Jeong Park, PhD Assistant Professor, Department of Diagnostic Radiology, Yonsei University, College of Medicine and Division of Nuclear Medicine, Severance Hospital Director, Laboratory of Molecular Neuroimging Technology http://neuroimage.yonsei.ac.kr Tel) 82-2-2228-2363, Fax) 82-2-393-3035 Cellur) 82-10-4220-1003 _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer -- Douglas N. Greve, Ph.D. MGH-NMR Center [EMAIL PROTECTED] Phone Number: 617-724-2358 Fax: 617-726-7422 |
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