[Insight-users] GradientDifferenceImageToImageMetric?

[D.F.Habets]

Hello everyone,

    I am trying to use the itkGradientDifferenceImageToImageMetric, but 
cannot get it to return anything but zero values for the Derivative. I 
looked through the list archive and found some references to bugs that 
were fixed in it, but could it be it's still problematic in the latest 
stable release?

I looked at the code and it uses a harcoded 0.001 delta in the calculation 
of the gradient and I didn't see that in any other 
ImageToImageMetric.

So my question is, does it actually work? Why is the delta hardcoded to 
0.001?

Thanks for your input,

Damiaan