Thanks a lot! what do you mean by iterative smoothing, is it heat kernel smoothing? Attached is a paper about curvature of UCLA, in which I highlight some part of it. firstly, they average the mean curvature within 3mm, then obtain its absolute value, Then they further smoothed the absolute mean curvature using heat kernel smoothing. I do not know what is the difference between averaging and iterative smoothing. By the way, can I get the absolute value of a curv file using build-in function rather than load it into matlab and then write it back to binary files? yczhang Thanks
--- 09年6月1日，周一, Bruce Fischl fischl@nmr.mgh.harvard.edu 写道：
发件人: Bruce Fischl fischl@nmr.mgh.harvard.edu 主题: Re: [Freesurfer] A problem about average curvature value 收件人: "Zhangyuanchao" woshizhangyc@yahoo.cn 抄送: "freesurfer" freesurfer@nmr.mgh.harvard.edu 日期: 2009年6月1日,周一,下午10:36
Hi yczhang,
yes, mris_average_curvature will do this on the surfae. It uses iterative averaging, but this converges to a Gaussian. Doug: can you post the formula that translates number of iterations into fwhm?
thanks Bruce
p.s. remember to include the -w switch otherwise it won't write out the results.
On Mon, 1 Jun 2009, Zhangyuanchao wrote:
Is there any build-in function that I can average a curvature file with Radius of 4mm on the surface, for example, lh.pial.H.crv file. in addition, lh.curv are smoothed in some way, is it smoothed simply by averaging the values? Thanks! Best Regards, yczhang
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Zhangyuanchao wrote:
By the way, can I get the absolute value of a curv file using build-in function rather than load it into matlab and then write it back to binary files?
$>mris_calc -o lh.abs.curv lh.curv abs
This will calculate the absolute value of the curv file 'lh.curv' and save to 'lh.abs.curv'.
It is iterative. The heat kernel stuff does not actually work.
doug
Zhangyuanchao wrote:
Thanks a lot!
what do you mean by iterative smoothing, is it heat kernel smoothing?
Attached is a paper about curvature of UCLA, in which I highlight some part of it.
firstly, they average the mean curvature within 3mm, then obtain its absolute value, Then they further smoothed the absolute mean curvature using heat kernel smoothing.
I do not know what is the difference between averaging and iterative smoothing.
By the way, can I get the absolute value of a curv file using build-in function rather than load it into matlab and then write it back to binary files?
yczhang
Thanks
--- *09年6月1日，周一, Bruce Fischl /fischl@nmr.mgh.harvard.edu/* 写道：
发件人: Bruce Fischl <fischl@nmr.mgh.harvard.edu> 主题: Re: [Freesurfer] A problem about average curvature value 收件人: "Zhangyuanchao" <woshizhangyc@yahoo.cn> 抄送: "freesurfer" <freesurfer@nmr.mgh.harvard.edu> 日期: 2009年6月1日,周一,下午10:36 Hi yczhang, yes, mris_average_curvature will do this on the surfae. It uses iterative averaging, but this converges to a Gaussian. Doug: can you post the formula that translates number of iterations into fwhm? thanks Bruce p.s. remember to include the -w switch otherwise it won't write out the results. On Mon, 1 Jun 2009, Zhangyuanchao wrote: > Is there any build-in function that I can average a curvature file with Radius of 4mm on the surface, for example, lh.pial.H.crv file. in addition, lh.curv are smoothed in some way, is it smoothed simply by averaging the values? > > Thanks! > > Best Regards, > yczhang > > > ___________________________________________________________ > ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ > http://card.mail.cn.yahoo.com/
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