[vtkusers] vtkImageReslice : scalar value range altered? (by cubic interpolation)

[Marius S Giurgi]

Does anyone know why the scalar value range (min/max) is altered by the 
vtkImageReslice when using the cubic interpolation?

I have a volume (181x217x181 double) whose scalar value range is  (0, 
1). I perform a rigid transformation on it (rotation, translation etc). 
The linear interpolation preserves the scalar value range (0, 1) but 
the cubic interpolation does not. E.g. for a particular transformation 
(RotateX 20) the scalar range becomes (-0.2167, 1.1854).

Remark: Even if the scalars are cropped by the given transformation 
(thus losing some values), the interpolated values should still remain 
within the original range (0, 1). Is this a bug or should certain 
parameters be set in vtkImageReslice to avoid such scalar value 
alteration?

thanks
marius