[IGSTK-Developers] Preparation for release

[Andinet Enquobahrie]

Hi Julien,

Digging into the code......here is what I found out about the tolerance 
parameter.

The tolerance parameter is defined in the test driver program 
(igstkTestMain.h). This class internally uses the 
itk::DifferenceImageFilter.  This filter performs pixel by pixel 
intensity comparison. One of the parameters of this filter is difference 
threshold. And the tolerance value defined in igstkTestMain.h is set to 
to this threshold. When a a pixel by pixel intensity comparison is done 
, if the absolute difference is greater than this threshold then the 
difference is added to the difference accumulator (totaldifference), 
otherwise it is ignored. The test driver program (igstkTest) reads the 
accumulated total difference and if the sum is different from zero, the 
test is flagged as failure and a difference image is generated for the 
dashboard.

I think this is not a good measure of similarity evaluation of two 
images. I suggest looking at the mean difference instead of the total 
difference and also add a second threshold to evaluate the mean difference.

Any thoughts on the improvement?

Andinet

PS:  the failure of your regression test on the linux machines is a 
similar issue with the other regression tests. this is mainly due to 
openGL rendering artifact. I can think of two options to resolve this 
issue. Either use a tolearnce measure ( after redefining it in a better 
way) to accomodate this artifact or generate different baseline images 
for windows and linux machines.












> Hi Luis,
>
> Most of the classes are almost ready to be moved. I plan to increase 
> the coverage today.
> When do you want to move the files? How about tomorrow evening?
>
> Also, the igstkVascularNetworkReaderTest is now a regression test and 
> for some reasons it's not passing on linux because of some bright 
> pixels. What is the best way to deal with that? increase the tolerance?
> BTW, What does the tolerance means?
>
> Thanks for your inputs on this,
>
> Julien
>
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