[Insight-users] About the MultiScaleHessianBasedMeasureImageFilter's function GetHessianOutput()

[Wang Zhimin]

Dear all,

I am a newbie to ITK. I currently want to compute the hessian matrix, eigen vector out of some volume CT images. I found that I can use itk::MultiScaleHessianBasedMeasureImageFilter, or itk::HessianRecursiveGaussianImageFilter plus itk::SymmetricEigenAnalysis and SymmetricSecondRankTensor image iterator to finish the job. Am I right?

For the itk::MultiScaleHessianBasedMeasureImageFilter, I understand that I can turn the GenerateHessianOutputOn() function to compute the Hessian image and use GetHessianOutput() to get the SymmetricSecondRankTensor image. Is this a correct procedure? If yes, so here comes my question. Since the multi scale hessian filter is multi scale, if I use GetHessianOutput() function, what scale is the Hessian output of?

Suppose my volume image dimension is 3, how can I access all the values in Hessian matrix? Can I use H[][] to access all 9 values? Or I can only access 6 and I need to fill up all the rest based on symmetric rule?

For my second option, from HessianRecursiveGaussianImageFilter -> SymmetricSecondRankTensor image -> SymmetricEigenAnalysis -> eigen vector, will it work as predicted? 

Sorry for so many questions. 

Thank you and best regards,
Zhimin

Research Fellow
Institute for Infocomm Research
A-STAR, Singapore


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