[Insight-developers] HessianObjectnessMeasureImageFilter Improvements and MultiScale progress

[Bradley Lowekamp]

Hello,

I just added progress support to MultiScaleHessianBasedMeasureImageFilter and committed it. As this filter is in review and this is a minor feature to add I just went ahead with it. Unfortunately, I was unable to create a test to verify that there is in fact progress as the SimpleFilterWatch never raises an exception with no progress:

http://public.kitware.com/cgi-bin/viewcvs.cgi/Code/Review/itkMultiScaleHessianBasedMeasureImageFilter.txx?root=Insight&r1=1.13&r2=1.14&sortby=date


I have all so made some more significant improvements to the HessianObjectnessMeasureImageFilter. These include:

1) Adding progress
2) Multi-threading the computation
3) Removing SymmetricEigenAnalysisImageFilter in favor of SysmmetricEigenAnalysis in the multithreaded methods
4) Safe guarding when Alpha, Beta, or Gamma are zero by taking the limit of the equations segment. Specifically,
   a) When Alpha or Gamma are zero then that term becomes 1
  b) When Beta is zero that term become 0 (actually the whole equation does)

The biggest impact of these changes are a 30% reduction in memory by the removal of the output of the Eigen filter's image. And 10-40% performance improvement from the multithreading, and better cpu utilization. I have attached the modified txx file. (hopefully that's not too big )

These changes should not have an impact on the results of the filter, and I believe are fully backwards compatible. This filter is also in review, so I think is should be ok.

Additionally, Hessian3DToVesselnessMeasureImageFilter looks like it was used to write this class as it's very similar. A similar change could easily be made to this filter to yield the same benefits. Again, I don't think there are any compatibility issues. (unless one relied on no progress or not full CPU utilization ).

Brad




========================================================
Bradley Lowekamp  
Lockheed Martin Contractor for
Office of High Performance Computing and Communications
National Library of Medicine 
blowekamp at mail.nih.gov


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