[Insight-users] SetNumberOfSpatialSamples has no effect on computation time???

[Luis Ibanez]

Hi Pinpress,

You will have to increase by a lot the number of samples
in order to notice an effect in the computation time.

If your real goal is to speed up the registration process,
the most important thing to do is to make sure that
you are compiling for "Release" mode, and to check
if all the cores of your processor are being used at
run time.


     Regards,


            Luis



--------------------------------
On Fri, May 7, 2010 at 10:43 AM, pinpress <sb_ji at yahoo.com> wrote:
>
> Dear all,
>
> I am performing 3D image registration with data set size of
> 256-by-256-by-124. Using normalized MI, or correlation coefficient, it's
> really slow. Therefore, I have purposefully set SetNumberOfSpatialSamples( )
> to a small number, e.g., 10% of the total number of voxels. To my dismay, it
> does not seem to have any effect on the computation time.
>
> Can I ask what's the reason? I have already set the optimization flags to be
> "ON" when compiling ITK using cmake. Therefore, this function does influence
> computation time when I use Mattes MI or Mean Squares Difference as the
> similarity measure.
>
> Please help. Thanks!
> --
> View this message in context: http://old.nabble.com/SetNumberOfSpatialSamples-has-no-effect-on-computation-time----tp28486979p28486979.html
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>
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