ENH: Add IsSameImageGeometryAs convenience method to ImageBase

Closes InsightSoftwareConsortium#3536.
dzenanz · Feb 26, 2024 · a7c0f32 · a7c0f32
1 parent ef28b0f
commit a7c0f32
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Showing 3 changed files with 51 additions and 4 deletions.
diff --git a/Modules/Core/Common/include/itkImageBase.h b/Modules/Core/Common/include/itkImageBase.h
@@ -768,6 +768,24 @@ class ITK_TEMPLATE_EXPORT ImageBase : public DataObject
   bool
   VerifyRequestedRegion() override;
 
+  /** Checks whether the images' pixels with the same index occupy the same physical space.
+   * Compares the origin, spacing, and direction for equality within provided tolerances.
+   * There is no check for valid regions in between the images. */
+  bool
+  IsCongruentImageGeometry(const ImageBase * otherImage, double coordinateTolerance, double directionTolerance) const;
+
+  /** Check whether this image and the other image have the same grid in physical space.
+   * Compares largest possible regions for equality, and the origin, spacing,
+   * and direction cosines for equality within provided tolerances.
+   * See also: ImageToImageFilter, namely:
+   * https://github.com/InsightSoftwareConsortium/ITK/blob/v5.3.0/Modules/Core/Common/include/itkImageToImageFilter.h#L78-L92
+   * https://github.com/InsightSoftwareConsortium/ITK/blob/v5.3.0/Modules/Core/Common/src/itkImageToImageFilterCommon.cxx#L26-L27
+   */
+  bool
+  IsSameImageGeometryAs(const ImageBase * otherImage,
+                        double            coordinateTolerance = 1e-6,
+                        double            directionTolerance = 1e-6) const;
+
   /** INTERNAL This method is used internally by filters to copy meta-data from
    * the output to the input. Users should not have a need to use this method.
    *

diff --git a/Modules/Core/Common/include/itkImageBase.hxx b/Modules/Core/Common/include/itkImageBase.hxx
@@ -398,6 +398,38 @@ ImageBase<VImageDimension>::VerifyRequestedRegion()
 }
 
 
+template <unsigned int VImageDimension>
+bool
+ImageBase<VImageDimension>::IsCongruentImageGeometry(const ImageBase * otherImage,
+                                                     double            coordinateTolerance,
+                                                     double            directionTolerance) const
+{
+  // check that the image occupy the same physical space, and that
+  // each index is at the same physical location
+
+  // tolerance for origin and spacing depends on the size of pixel
+  // tolerance for directions a fraction of the unit cube.
+  const SpacePrecisionType coordinateTol =
+    itk::Math::abs(coordinateTolerance * this->GetSpacing()[0]); // use first dimension spacing
+
+  return this->GetOrigin().GetVnlVector().is_equal(otherImage->GetOrigin().GetVnlVector(), coordinateTol) &&
+         this->GetSpacing().GetVnlVector().is_equal(otherImage->GetSpacing().GetVnlVector(), coordinateTol) &&
+         this->GetDirection().GetVnlMatrix().as_ref().is_equal(otherImage->GetDirection().GetVnlMatrix().as_ref(),
+                                                               directionTolerance);
+}
+
+
+template <unsigned int VImageDimension>
+bool
+ImageBase<VImageDimension>::IsSameImageGeometryAs(const ImageBase * otherImage,
+                                                  double            coordinateTolerance,
+                                                  double            directionTolerance) const
+{
+  return this->IsCongruentImageGeometry(otherImage, coordinateTolerance, directionTolerance) &&
+         this->GetLargestPossibleRegion() == otherImage->GetLargestPossibleRegion();
+}
+
+
 template <unsigned int VImageDimension>
 void
 ImageBase<VImageDimension>::SetBufferedRegion(const RegionType & region)

diff --git a/Modules/Core/Common/include/itkImageToImageFilter.hxx b/Modules/Core/Common/include/itkImageToImageFilter.hxx
@@ -184,10 +184,7 @@ ImageToImageFilter<TInputImage, TOutputImage>::VerifyInputInformation() ITKv5_CO
       const SpacePrecisionType coordinateTol =
         itk::Math::abs(this->m_CoordinateTolerance * inputPtr1->GetSpacing()[0]); // use first dimension spacing
 
-      if (!inputPtr1->GetOrigin().GetVnlVector().is_equal(inputPtrN->GetOrigin().GetVnlVector(), coordinateTol) ||
-          !inputPtr1->GetSpacing().GetVnlVector().is_equal(inputPtrN->GetSpacing().GetVnlVector(), coordinateTol) ||
-          !inputPtr1->GetDirection().GetVnlMatrix().as_ref().is_equal(inputPtrN->GetDirection().GetVnlMatrix().as_ref(),
-                                                                      this->m_DirectionTolerance))
+      if (!inputPtr1->IsCongruentImageGeometry(inputPtrN, m_CoordinateTolerance, m_DirectionTolerance))
       {
         std::ostringstream originString, spacingString, directionString;
         if (!inputPtr1->GetOrigin().GetVnlVector().is_equal(inputPtrN->GetOrigin().GetVnlVector(), coordinateTol))