[Insight-users] RecursiveGaussianImageFilter

[Silvano Agliozzo]

Hi to everyones,

I implemented an application for the calculation of first and second order
partial derivatives of a 3D image by using the
RecursiveGaussianImageFilter. I observed a strange behaviour by adding a
large costant (positive and negative) to the values of the 3D image.  
Actually the results are completely different each other and with respect
to the case without the addition of the costant. This does not happen by
using the DerivativeImageFilter, but it is unfortunately slower. From 
the theory, adding a constant to a function does not change the value of 
its derivativesB.

I do not understand what's wrong in this filter or with my implementation.
Any suggestions ?

thank you,

Silvano