[Insight-users] Registration works on Debug, on Release doesn't

[Oscar Esteban Sanz-Dranguet]

Hi,

Based on Examples\Registration\ImageRegistrationHistogramPlotter.cxx, 
I'm trying to perform a registration between a T1 MRI slice and a 13,8 
degrees rotated PET slice.

I've configured every block, and I get a great result in Debug mode.

When I try to use the same code, under the same conditions except build 
type (now, in Release mode), the registration doesn't work.

On debug mode, the optimizer (RegularStepGradientDescentOptimizer) 
starts with a rotation of 0.175 rad. Next step, it tries with 0.350 rad 
and next step returns to ~0.19 rad. After 50 iterations, rotation is 
about 0,24 and result is great.

On Release mode, it starts with a rotation of -0.175 rad, and every step 
it sums up another -0.175 rad. It stops when the maximum iterations 
number is reached.

I can't find why this is happening, because all parameters are the same 
for the two experiments.

Thank you very much in advanced,

-- 
Oscar Esteban
BIT - UPM (http://www.die.upm.es/im/)
+34 915 495700  ext.4248