Visual studio itk Hessian3DToVesselnessMeasureImageFilter，使用SetAlpha

我是itk的新手。我需要使用itk进行血管分割。我不明白为什么itk Hessian3DToVesselnessMeasureImageFilter中使用了

SetAplha1

和

SetAlpha2

？这个角色是什么

 using HessianFilterType = itk::HessianRecursiveGaussianImageFilter<ImageType>;
 HessianFilterType::Pointer hessianFilter = HessianFilterType::New();
hessianFilter->SetInput(filter_toitkimage->GetOutput());
hessianFilter->SetSigma(1.0);//does this will determine the spacing between each dicom image slices?


using VesselnessMeasureFilterType = itk::Hessian3DToVesselnessMeasureImageFilter<PixelType>;
VesselnessMeasureFilterType::Pointer vesselnessFilter = VesselnessMeasureFilterType::New();
vesselnessFilter->SetInput(hessianFilter->GetOutput());
vesselnessFilter->SetAlpha1(0.5);
vesselnessFilter->SetAlpha2(2.0); 

使用HessianFilterType=itk:：HessianRecursiveGaussianImageFilter；
HessianFilterType:：指针hessianFilter=HessianFilterType:：New（）；
hessianFilter->SetInput（filter_toitkimage->GetOutput（））；
hessianFilter->SetSigma（1.0）//这是否将确定每个dicom图像切片之间的间距？
使用VesselnessMeasureFilterType=itk:：Hessian3DToVesselnessMeasureImageFilter；
VesselnessMeasureFilterType:：指针vesselnessFilter=VesselnessMeasureFilterType:：New（）；
vesselnessFilter->SetInput（hessianFilter->GetOutput（））；
vesselnessFilter->SetAlpha1（0.5）；
vesselnessFilter->SetAlpha2（2.0）；

Sigma

确定特征的比例。例如，西格玛1.0适用于直径约2-3mm的血管，而西格玛5.0适用于直径10-15mm的血管（想想主动脉、腔静脉）

关于

Alpha

参数，要求查看中的描述