[Insight-users] how to calculate the derivatons of images in DeformableRegistration4?

[shengzhouxu]

Hi All,

In the example DeformableRegistration4.cxx, the itkMeanSquaresImageToImageMetric is used as the metric method, and the optimization method is LBFGS, and in the LBFGS the derivations have to be calculated to obtain the Hessian matrix. Generally the derivation is easy to calculate, such as f(x)= x^2 , f’(x)=2x, but how to calculate the derivatons of images?  because I don’t know the expression of the function, and how we explain the derivations of images? would anyone please explain this? Thanks every much!

2009-03-06 



shengzhouxu 
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