[MINC-users] mincblur with FWHM <= voxel dims

[Vladimir S. Fonov]

Hello,

I have my own implementation of gaussian blurring in EZminc:
https://github.com/vfonov/EZminc/blob/master/tools/fast_blur.cpp
(fast_blur binary in the minc-toolkit) .
I think it behaves properly for any blurring kernel size, and it 
produces the same results as mincblur when fwhm> 2*voxel size

On 24/06/2012 5:20 PM, Alex Zijdenbos wrote:
> I did some experimenting by blurring a binary cube in an image and
> monitoring the mean value (generously padded and away from the image
> edge to avoid edge effects). See this graph: ​mincblur_mean.png
> (http://cl.ly/2V472I092L3U3R3e0k02) which shows the mean value of the
> 1mm isotropic image as a function of kernel FWHM running from 0.2 to
> 5.0mm with 0.1mm steps. You can see that for FWHM<  2*voxel_dim the
> mean signal starts to go up rather steeply. By contrast, the orange
> HR line is from the same image, but obtained by first upsampling it
> to a relatively high (0.1mm) resolution, performing the blur at that
> resolution, and downsampling the result. I would argue that, barring
> some resampling effects, these curves should be the same.

-- 
Best regards,

  Vladimir S. Fonov ~ vladimir <dot> fonov <at> gmail <dot> com