[Insight-developers] Uniform registration results

[Luis Ibanez]

Hi Daniel,

That's great !

Thanks for replacing the random number
generator in the iterator.

I'll be happy to double check the results,
if you send me the patch. Once we check them,
we can simply commit new baseline images, that
this time should probably be the same for all
platforms.


   Thanks


      Luis


------------------------------------
Blezek, Daniel J (Research) wrote:
> One problem that has plagued me for some time is the different registration results from different platforms.  The problem is in the Random image iterator used to draw samples from the images being registered.  On Unix-like systems, drand48 is used, under Windows (as best I can make out) there is a C++ implementation.  They give a different sequence of random numbers, as you might expect.  This leads to different minimum in the registration process.
> 
> To fix this, I've changed the random iterators to use the MersenTwister RNG.  Some tests fail because they are not exactly the same (registration is off by < 0.1 pixels/mm).  The tests that fail are:
> 
> The following tests FAILED:
>         965 - ImageRegistration4oTest (Failed)
>         972 - ImageRegistration4Test (Failed)
>         979 - ImageRegistration13Test (Failed)
>         982 - ImageRegistration16Test (Failed)
>         984 - MultiResImageRegistration1Test (Failed)
>         985 - MultiResImageRegistration2Test (Failed)
> 
> I've verified the final parameters are very close to the previous results.  Is there an owner of these tests?  If so, can I send a patch and have you verify the results?  Otherwise I'll plan to check the code in with new baseline images.
> 
> Regards,
> -dan
> 
> 
> Daniel Blezek, PhD
> GE Global Research
> Computer Scientist
> 
> T 518 387 5481
> F 518 387 6981
> D *833-5481
> E blezek at research.ge.com
> www.research.ge.com
> 
> 1 Research Circle
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> 
> General Electric Company
> 
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