[Insight-users] MultiScaleHessianBasedMeasureImageFilter + HessianToObjectnessMeasureImageFilter, empty image

[Ravi Samala]

(1) Try HessianPixelType of type double.(2) Instead of HessianToObjectnessMeasureImageFilter use Hessian3DToVesselnessMeasureImageFilter.
RS.

Date: Mon, 11 Oct 2010 12:22:02 +0200
From: sergio.vera at alma3d.com
To: insight-users at itk.org
Subject: [Insight-users] MultiScaleHessianBasedMeasureImageFilter + HessianToObjectnessMeasureImageFilter, empty image

Hello all
Currently I use HessianRecursiveGaussianImageFilter Hessian3DToVesselness to enhance coronary arteries in CTA images. I would like to test the multiscale hessian enhancement using MultiScaleHessianBasedMeasureImageFilter and HessianToObjectnessMeasureImageFilter, however, I'm only obtainig empty (black) images as a result of the enhancement and the scales.

Here is a snippet of the code: 
typedef itk::ThresholdImageFilter<ITKImgInType> ThrFilter;
ThrFilter::Pointer thr = ThrFilter::New();
thr->SetInput(&a_imgIn);
thr->SetLower(80); 
thr->SetUpper(10000); // remove other parts of the image with low values 


typedef itk::CastImageFilter<ITKImgInType, F1d3ITKImgType> CastFilter;
CastFilter::Pointer cast2float = CastFilter::New();
cast2float->SetInput(thr->GetOutput());


typedef itk::SymmetricSecondRankTensor<float, 3> HessianPixelType;
typedef itk::Image<HessianPixelType, 3> HessianImage;


typedef itk::MultiScaleHessianBasedMeasureImageFilter <F1d3ITKImgType, HessianImage, F1d3ITKImgType> HessianFilter;

HessianFilter::Pointer hessian = HessianFilter::New();
hessian->SetInput(cast2float->GetOutput());
hessian->SetNumberOfSigmaSteps(6);
hessian->SetSigmaStepMethodToEquispaced();
hessian->SetSigmaMinimum(1.1);
hessian->SetSigmaMinimum(2.4); // This sizes in mm?
hessian->SetGenerateHessianOutput(true);
hessian->SetGenerateScalesOutput(true);


typedef itk::HessianToObjectnessMeasureImageFilter <HessianImage, F1d3ITKImgType> ObjectnessFilter;

ObjectnessFilter::Pointer vesselFilter = ObjectnessFilter::New();
vesselFilter->SetScaleObjectnessMeasure(false);
vesselFilter->SetBrightObject(true);
vesselFilter->SetAlpha(0.5);
vesselFilter->SetBeta(0.5);
vesselFilter->SetGamma(5.0);
vesselFilter->SetObjectDimension(1); // vessels
	
hessian->SetHessianToMeasureFilter(vesselFilter);
	
try {
  hessian->Update();
} catch (const itk::ExceptionObject& e) {
  std::cerr << __FUNCTION__ << ": itk::ExceptionObject caught: " << e.what() << '\n';

  return eErrorITKExceptionRunningSegmentation;
} catch (...) {
  std::cerr << __FUNCTION__ << ": '...' exception caught.\n";

  return eErrorUnknownExceptionStartingSegmentation;
}
spy::WriteFile<F1d3ITKImgType>(__FUNCTION__, "Vesselness.mhd", *(hessian->GetOutput()), true);

spy::WriteFile<F1d3ITKImgType>(__FUNCTION__, "Scales.mhd", *(hessian->GetScalesOutput()), true);

spy::WriteFile<F1d3ITKImgType>(__FUNCTION__, "Converted2Float.mhd", *(cast2float->GetOutput()), true);

The two first images written to disk are empty. Correct size and spacing but only black voxels. Converted2Float.mhd seems to be correcttly convertedThanks in advance
-- 
Sergio Vera


 Alma IT Systems
 C/ Vilana, 4B, 4º 1ª
 08022 Barcelona
 T. (+34) 932 380 592
 www.alma3d.com



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