[vtkusers] Computing 2nd order derivatives of images

[Thomas Deschamps]

Berk Geveci wrote:

> There is also vtkCellDerivatives but it is very slow compared to
> vtkImageDifference since it actually uses the dataset interface.
> I would write my own if I were you. It shouldn't take more than 5 minutes :-)

Sure...
But I was looking for an algorithm more efficient, computing smoothing and derivatives in the
Fourier domain for example.
1) Computing the fft of the image
2) convolving with different kernels for each partial derivative
3) doing an inverse fft
Thanks anyway