[Insight-users] Registration of certain image pairs throws *Too Many Samples Map Outside*

[Oscar Esteban Sanz-Dranguet]

Hi all,

I need some advises about itk debuging. When I try to register some 
concrete pairs of images, I get before first iteration the "itk::ERROR: 
MattesMutualInformationImageToImageMetric(0x7fa884187190): Too many 
samples map outside moving image buffer".

1) Initialization: Initialization consists of a Moments initializer. I 
write the moving image resampled with the initialized transform and 
using the fixed image as reference. It appears to be correctly centered 
over the fixed image.

2) Scaling Parameters: For mentioned images pairs I set the (affine) 
transform scaling parameters with high values (>100) to avoid huge 
optimizer steps, combined with a very low learning rate 
(GradientDescentOptimizer). The InitialTransformParametersOfNextLevel 
(once initialization is applied) are [1, 0, 0, 0, 1, 0, 0, 0, 1, 
-240.098, 258.401, -90.3593]. The metric still throws the exception with 
those parameters before first iteration.

3) Optimizer Steps: as I told before, I use low learning rates (<0.001) 
to assess that the step is little enough.

What checks am I missing? How should I debug my application?

Best,

-- 
Oscar Esteban
BIT - UPM (http://www.die.upm.es/im/)
+34 913 366 827 ext.4248