diff --git a/include/rtkDePierroRegularizationImageFilter.h b/include/rtkDePierroRegularizationImageFilter.h
index 3e738a139..70899ca2a 100644
--- a/include/rtkDePierroRegularizationImageFilter.h
+++ b/include/rtkDePierroRegularizationImageFilter.h
@@ -142,7 +142,7 @@ class ITK_EXPORT DePierroRegularizationImageFilter : public itk::ImageToImageFil
   CustomBinaryFilterPointerType   m_CustomBinaryFilter;
 
 private:
-  float m_Beta;
+  float m_Beta{ 0.01 };
 
 }; // end of class
 
diff --git a/include/rtkDePierroRegularizationImageFilter.hxx b/include/rtkDePierroRegularizationImageFilter.hxx
index f832212cd..502f0525f 100644
--- a/include/rtkDePierroRegularizationImageFilter.hxx
+++ b/include/rtkDePierroRegularizationImageFilter.hxx
@@ -27,8 +27,6 @@ template <class TInputImage, class TOutputImage>
 DePierroRegularizationImageFilter<TInputImage, TOutputImage>::DePierroRegularizationImageFilter()
 {
   this->SetNumberOfRequiredInputs(2);
-  // Set default parameters
-  m_Beta = 0.01;
 
   // Create each filter of the composite filter
   m_MultiplyConstant1ImageFilter = MultiplyImageFilterType::New();
diff --git a/include/rtkOSEMConeBeamReconstructionFilter.h b/include/rtkOSEMConeBeamReconstructionFilter.h
index bd1e5bf76..cb7939c54 100644
--- a/include/rtkOSEMConeBeamReconstructionFilter.h
+++ b/include/rtkOSEMConeBeamReconstructionFilter.h
@@ -213,20 +213,20 @@ class ITK_EXPORT OSEMConeBeamReconstructionFilter
 
 private:
   /** Number of projections processed before the volume is updated (several for OS-EM) */
-  unsigned int m_NumberOfProjectionsPerSubset;
+  unsigned int m_NumberOfProjectionsPerSubset{ 1 };
 
   /** Geometry object */
   ThreeDCircularProjectionGeometry::Pointer m_Geometry;
 
   /** Number of iterations */
-  unsigned int m_NumberOfIterations;
+  unsigned int m_NumberOfIterations{ 3 };
 
   /** PSF correction coefficients */
-  float m_SigmaZero;
-  float m_Alpha;
+  float m_SigmaZero{ -1 };
+  float m_Alpha{ -1 };
 
   /** Hyperparameter for the regularization */
-  float m_BetaRegularization;
+  float m_BetaRegularization{ 0.01 };
 
 }; // end of class
 
diff --git a/include/rtkOSEMConeBeamReconstructionFilter.hxx b/include/rtkOSEMConeBeamReconstructionFilter.hxx
index 07718778d..030d506eb 100644
--- a/include/rtkOSEMConeBeamReconstructionFilter.hxx
+++ b/include/rtkOSEMConeBeamReconstructionFilter.hxx
@@ -36,12 +36,6 @@ OSEMConeBeamReconstructionFilter<TVolumeImage, TProjectionImage>::OSEMConeBeamRe
 {
   this->SetNumberOfRequiredInputs(2);
 
-  // Set default parameters
-  m_NumberOfIterations = 3;
-  m_SigmaZero = -1;
-  m_Alpha = -1;
-  m_BetaRegularization = 0.01;
-
   // Create each filter of the composite filter
   m_ExtractFilter = ExtractFilterType::New();
   m_MultiplyFilter = MultiplyFilterType::New();
@@ -61,7 +55,6 @@ OSEMConeBeamReconstructionFilter<TVolumeImage, TProjectionImage>::OSEMConeBeamRe
 
   // Default parameters
   m_ExtractFilter->SetDirectionCollapseToSubmatrix();
-  m_NumberOfProjectionsPerSubset = 1; // Default is the OSEM behavior
 }
 
 template <class TVolumeImage, class TProjectionImage>
diff --git a/include/rtkZengBackProjectionImageFilter.h b/include/rtkZengBackProjectionImageFilter.h
index 6e71425f4..7e0085e83 100644
--- a/include/rtkZengBackProjectionImageFilter.h
+++ b/include/rtkZengBackProjectionImageFilter.h
@@ -162,10 +162,10 @@ class ITK_EXPORT ZengBackProjectionImageFilter : public BackProjectionImageFilte
   void
   operator=(const Self &) = delete; // purposely not implemented
 
-  float      m_SigmaZero;
-  float      m_Alpha;
-  VectorType m_VectorOrthogonalDetector;
-  PointType  m_centerVolume;
+  float      m_SigmaZero{ 1.5417233052142099 };
+  float      m_Alpha{ 0.016241189545787734 };
+  VectorType m_VectorOrthogonalDetector{ 0. };
+  PointType  m_centerVolume{ 0 };
 };
 
 } // end namespace rtk
diff --git a/include/rtkZengBackProjectionImageFilter.hxx b/include/rtkZengBackProjectionImageFilter.hxx
index 3eb4a1c61..491272024 100644
--- a/include/rtkZengBackProjectionImageFilter.hxx
+++ b/include/rtkZengBackProjectionImageFilter.hxx
@@ -40,12 +40,7 @@ template <class TInputImage, class TOutputImage>
 ZengBackProjectionImageFilter<TInputImage, TOutputImage>::ZengBackProjectionImageFilter()
 {
   // Set default parameters
-  m_SigmaZero = 1.5417233052142099;
-  m_Alpha = 0.016241189545787734;
-  m_VectorOrthogonalDetector[0] = 0;
-  m_VectorOrthogonalDetector[1] = 0;
   m_VectorOrthogonalDetector[2] = 1;
-  m_centerVolume.Fill(0);
 
   // Create each filter of the composite filter
   m_AddImageFilter = AddImageFilterType::New();
diff --git a/include/rtkZengForwardProjectionImageFilter.h b/include/rtkZengForwardProjectionImageFilter.h
index a75496287..4cece2e56 100644
--- a/include/rtkZengForwardProjectionImageFilter.h
+++ b/include/rtkZengForwardProjectionImageFilter.h
@@ -153,10 +153,10 @@ class ITK_EXPORT ZengForwardProjectionImageFilter : public ForwardProjectionImag
   void
   operator=(const Self &) = delete; // purposely not implemented
 
-  float      m_SigmaZero;
-  float      m_Alpha;
-  VectorType m_VectorOrthogonalDetector;
-  PointType  m_centerVolume;
+  float      m_SigmaZero{ 1.5417233052142099 };
+  float      m_Alpha{ 0.016241189545787734 };
+  VectorType m_VectorOrthogonalDetector{ 0. };
+  PointType  m_centerVolume{ 0 };
 };
 
 } // end namespace rtk
diff --git a/include/rtkZengForwardProjectionImageFilter.hxx b/include/rtkZengForwardProjectionImageFilter.hxx
index c9cb5c2d3..cf1792d84 100644
--- a/include/rtkZengForwardProjectionImageFilter.hxx
+++ b/include/rtkZengForwardProjectionImageFilter.hxx
@@ -40,12 +40,7 @@ template <class TInputImage, class TOutputImage>
 ZengForwardProjectionImageFilter<TInputImage, TOutputImage>::ZengForwardProjectionImageFilter()
 {
   // Set default parameters
-  m_SigmaZero = 1.5417233052142099;
-  m_Alpha = 0.016241189545787734;
-  m_VectorOrthogonalDetector[0] = 0;
-  m_VectorOrthogonalDetector[1] = 0;
   m_VectorOrthogonalDetector[2] = 1;
-  m_centerVolume.Fill(0);
 
   // Create each filter of the composite filter
   m_RegionOfInterest = RegionOfInterestFilterType::New();