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Forum TrackVis Usage Stats tab

Stats tab
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UserPost

12:34 am
April 3, 2010


johnc

Member

posts 13
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1

Hello,

 

Could you explain a bit about how TrackVis calculates the stats for a track group? I'm trying to duplicate these in MATLAB to help verify that my interface between MATLAB and TrackVis is working OK. My calculated values (mean FA, FA SD, # of voxels, and especially FA range) slightly differ from what is displayed in TrackVis, so I'm trying to figure out why. Is there any thresholding, interpolation, or other processing occuring that may account for this? Also, does TrackVis calculate stats only among the unique # of voxels, or does it count voxels that are repeatedly visited more than once? Thanks,

 

John

1:00 pm
April 5, 2010


Ruopeng

Admin

posts 406
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2

Hi John,

To calculate stats, TrackVis first converts a track to a series of continuous voxels by its coordinates. Then it computes the mean scalar out of these voxels. The mean scalar of a TrackGroup is the mean of those scalars weighted by track length. So yes, it counts repeated voxels.

Ruopeng

4:46 pm
April 5, 2010


johnc

Member

posts 13
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3

Perfect. Thank you, Ruopeng. -John
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