STYLE: Replace declare-then-assign of region iterator variables in *.hxx

Merged declaration and assignment together, for local region iterator variables.

Removed `LocalLevelSetImageType` from ExtensionVelocitiesImageFilter, as it
has become unnecessary with this commit.

Author: N-Dekker

Modules/Filtering/BinaryMathematicalMorphology/include/itkBinaryMorphologyImageFilter.hxx

@@ -114,8 +114,7 @@ BinaryMorphologyImageFilter<TInputImage, TOutputImage, TKernel>::AnalyzeKernel()
   tmpSEImage->Allocate();
 
   // copy
-  ImageRegionIterator<BoolImageType> kernelImageIt; // iterator on image
-  kernelImageIt = ImageRegionIterator(tmpSEImage, tmpSEImage->GetRequestedRegion());
+  ImageRegionIterator kernelImageIt(tmpSEImage, tmpSEImage->GetRequestedRegion());
 
   kernel_it = KernelBegin;
 

Modules/Filtering/ImageFeature/include/itkHessian3DToVesselnessMeasureImageFilter.hxx

@@ -51,11 +51,10 @@ Hessian3DToVesselnessMeasureImageFilter<TPixel>::GenerateData()
   const typename EigenValueOutputImageType::ConstPointer eigenImage = m_SymmetricEigenValueFilter->GetOutput();
 
   // walk the region of eigen values and get the vesselness measure
-  EigenValueArrayType                  eigenValue;
-  ImageRegionConstIterator             it(eigenImage, eigenImage->GetRequestedRegion());
-  ImageRegionIterator<OutputImageType> oit;
+  EigenValueArrayType      eigenValue;
+  ImageRegionConstIterator it(eigenImage, eigenImage->GetRequestedRegion());
   this->AllocateOutputs();
-  oit = ImageRegionIterator(output, output->GetRequestedRegion());
+  ImageRegionIterator oit(output, output->GetRequestedRegion());
   while (!it.IsAtEnd())
   {
     // Get the eigen value

Modules/Registration/PDEDeformable/include/itkCurvatureRegistrationFilter.hxx

@@ -204,18 +204,13 @@ CurvatureRegistrationFilter<TFixedImage, TMovingImage, TDisplacementField, TImag
   (void)dt;
   const DisplacementFieldPointer update = this->GetUpdateBuffer();
 
-  ImageRegionConstIterator<DisplacementFieldType>   itInDeformation;
-  ImageRegionIterator<DisplacementFieldType>        itOutDeformation;
-  ImageRegionConstIterator<DisplacementFieldType>   itInUpdate;
-  ImageRegionConstIteratorWithIndex<FixedImageType> fixedImageIteratorWithIndex;
-
-  itInDeformation =
-    ImageRegionConstIterator(this->GetDisplacementField(), this->GetDisplacementField()->GetLargestPossibleRegion());
-  itOutDeformation =
-    ImageRegionIterator(this->GetDisplacementField(), this->GetDisplacementField()->GetLargestPossibleRegion());
-  itInUpdate = ImageRegionConstIterator(update, update->GetLargestPossibleRegion());
-  fixedImageIteratorWithIndex = ImageRegionConstIteratorWithIndex<FixedImageType>(
-    this->GetFixedImage(), this->GetFixedImage()->GetLargestPossibleRegion());
+  ImageRegionConstIterator          itInDeformation(this->GetDisplacementField(),
+                                           this->GetDisplacementField()->GetLargestPossibleRegion());
+  ImageRegionIterator               itOutDeformation(this->GetDisplacementField(),
+                                       this->GetDisplacementField()->GetLargestPossibleRegion());
+  ImageRegionConstIterator          itInUpdate(update, update->GetLargestPossibleRegion());
+  ImageRegionConstIteratorWithIndex fixedImageIteratorWithIndex(this->GetFixedImage(),
+                                                                this->GetFixedImage()->GetLargestPossibleRegion());
 
   const SizeValueType numberOfPixels = this->GetFixedImage()->GetLargestPossibleRegion().GetNumberOfPixels();
 

Modules/Segmentation/LevelSets/include/itkExtensionVelocitiesImageFilter.hxx

@@ -143,14 +143,9 @@ ExtensionVelocitiesImageFilter<TLevelSet, TAuxValue, VAuxDimension>::GenerateDat
   const double levelSetValue = this->GetLevelSetValue();
 
   // define iterators
-  using LocalLevelSetImageType = typename LevelSetType::LevelSetImageType;
-
   ImageRegionConstIterator inputIt(inputPtr, inputPtr->GetBufferedRegion());
   ImageRegionIterator      outputIt(outputPtr, outputPtr->GetBufferedRegion());
 
-  ImageRegionIterator<LocalLevelSetImageType> tempIt;
-
-
   ImageRegionIterator<AuxImageType> auxTempIt[VAuxDimension];
   ImageRegionIterator<AuxImageType> auxOutputIt[VAuxDimension];
 
@@ -178,7 +173,7 @@ ExtensionVelocitiesImageFilter<TLevelSet, TAuxValue, VAuxDimension>::GenerateDat
   m_Marcher->SetAuxiliaryTrialValues(m_Locator->GetModifiableAuxOutsideValues());
   m_Marcher->Update();
 
-  tempIt = ImageRegionIterator(tempLevelSet, tempLevelSet->GetBufferedRegion());
+  ImageRegionIterator tempIt(tempLevelSet, tempLevelSet->GetBufferedRegion());
 
   for (unsigned int k = 0; k < VAuxDimension; ++k)
   {