ENH: Add python_unittest/test_ElastixRegistrationMethod.py

Added a Python unittest based unit test for ElastixRegistrationMethod.

test/python_unittest/test_ElastixRegistrationMethod.py

@@ -0,0 +1,68 @@
+"""Module providing Python unit tests for itk.ElastixRegistrationMethod."""
+
+import unittest
+import itk
+
+
+class ElastixRegistrationMethodTestCase(unittest.TestCase):
+    """Tests itk.ElastixRegistrationMethod"""
+
+    def test_SimilarityTransform(self) -> None:
+        """Tests SimilarityTransform"""
+
+        def set_pixels_of_object(image, index_value: int, size_value: int) -> None:
+            for i in range(index_value, index_value + size_value):
+                for j in range(index_value, index_value + size_value):
+                    image.SetPixel([i, j], 1)
+
+        dimension = 2
+        ImageType = itk.Image[itk.F, dimension]
+        SizeType = itk.Size[dimension]
+
+        fixed_object_size_value = 32
+        fixed_object_index_value = fixed_object_size_value
+        fixed_image_size_value = 4 * fixed_object_size_value
+
+        moving_object_size_value = 40
+        moving_object_index_value = moving_object_size_value
+        moving_image_size_value = 4 * moving_object_size_value
+
+        fixed_image = ImageType.New(Regions=SizeType.Filled(fixed_image_size_value))
+        fixed_image.AllocateInitialized()
+        set_pixels_of_object(
+            fixed_image, fixed_object_index_value, fixed_object_size_value
+        )
+
+        moving_image = ImageType.New(Regions=SizeType.Filled(moving_image_size_value))
+        moving_image.AllocateInitialized()
+        set_pixels_of_object(
+            moving_image, moving_object_index_value, moving_object_size_value
+        )
+
+        parameter_map = {
+            "ImageSampler": ("Full",),
+            "MaximumNumberOfIterations": ("50",),
+            "Metric": ("AdvancedNormalizedCorrelation",),
+            "Optimizer": ("AdaptiveStochasticGradientDescent",),
+            "Transform": ("SimilarityTransform",),
+        }
+        registration = itk.ElastixRegistrationMethod[ImageType, ImageType].New(
+            FixedImage=fixed_image,
+            MovingImage=moving_image,
+            ParameterObject=itk.ParameterObject.New(ParameterMap=parameter_map),
+        )
+        registration.Update()
+        transform_parameter_object = registration.GetTransformParameterObject()
+        transform_parameters = transform_parameter_object.GetParameter(
+            0, "TransformParameters"
+        )
+        self.assertEqual(len(transform_parameters), 4)
+        self.assertAlmostEqual(
+            float(transform_parameters[0]),
+            float(moving_object_size_value) / float(fixed_object_size_value),
+            1,
+        )
+
+
+if __name__ == "__main__":
+    unittest.main()