--- a
+++ b/src/itkPyVnl.hxx
@@ -0,0 +1,213 @@
+/*=========================================================================
+ *
+ *  Copyright Insight Software Consortium
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *         http://www.apache.org/licenses/LICENSE-2.0.txt
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ *=========================================================================*/
+#ifndef itkPyVnl_hxx
+#define itkPyVnl_hxx
+
+#include "itkPyVnl.h"
+#include <stdexcept>
+
+namespace itk
+{
+
+template<class TElement>
+PyObject *
+PyVnl<TElement>
+::_GetArrayViewFromVnlVector( VectorType * vector)
+{
+  PyObject *                  memoryView    = NULL;
+  Py_buffer                   pyBuffer;
+  memset(&pyBuffer, 0, sizeof(Py_buffer));
+
+  size_t                      elementSize   = sizeof(DataType);
+  int                         res           = 0;
+
+  if( !vector )
+    {
+    throw std::runtime_error("Input vector is null");
+    }
+
+  DataType *buffer = vector->data_block();
+
+  void * vectorBuffer = (void *)( buffer );
+
+  // Computing the length of data
+  Py_ssize_t len = vector->size();
+  len *= elementSize;
+
+  res = PyBuffer_FillInfo(&pyBuffer, NULL, (void*)vectorBuffer, len, 0, PyBUF_CONTIG);
+  memoryView = PyMemoryView_FromBuffer(&pyBuffer);
+
+  PyBuffer_Release(&pyBuffer);
+
+  return memoryView;
+}
+
+template<class TElement>
+const typename PyVnl<TElement>::VectorType
+PyVnl<TElement>
+::_GetVnlVectorViewFromArray( PyObject *arr, PyObject *shape)
+{
+  PyObject *                  obj           = NULL;
+  PyObject *                  shapeseq      = NULL;
+  PyObject *                  item          = NULL;
+
+  Py_ssize_t                  bufferLength;
+  Py_buffer                   pyBuffer;
+  memset(&pyBuffer, 0, sizeof(Py_buffer));
+
+  size_t numberOfElements = 1;
+
+  const void *                buffer;
+
+  unsigned int                dimension     = 0;
+
+
+  size_t                      elementSize   = sizeof(DataType);
+  size_t                      len           = 1;
+
+  if(PyObject_GetBuffer(arr, &pyBuffer, PyBUF_CONTIG) == -1)
+    {
+    PyErr_SetString( PyExc_RuntimeError, "Cannot get an instance of NumPy array." );
+    PyBuffer_Release(&pyBuffer);
+    return VectorType();
+    }
+  else
+    {
+    bufferLength = pyBuffer.len;
+    buffer = pyBuffer.buf;
+    }
+
+  obj        = shape;
+  shapeseq   = PySequence_Fast(obj, "expected sequence");
+  dimension  = PySequence_Size(obj);
+
+  item = PySequence_Fast_GET_ITEM(shapeseq,0);// Only one dimension
+  numberOfElements = (size_t)PyLong_AsLong(item);
+
+  len = numberOfElements*elementSize;
+  if ( bufferLength != len )
+    {
+    PyErr_SetString( PyExc_RuntimeError, "Size mismatch of vector and Buffer." );
+    PyBuffer_Release(&pyBuffer);
+    return VectorType();
+    }
+  DataType * data = (DataType *)buffer;
+  VectorType output(data, numberOfElements);
+  PyBuffer_Release(&pyBuffer);
+
+  return output;
+}
+
+template<class TElement>
+PyObject *
+PyVnl<TElement>
+::_GetArrayViewFromVnlMatrix( MatrixType * matrix)
+{
+  PyObject *                  memoryView    = NULL;
+  Py_buffer                   pyBuffer;
+  memset(&pyBuffer, 0, sizeof(Py_buffer));
+
+  size_t                      elementSize   = sizeof(DataType);
+  int                         res           = 0;
+
+  if( !matrix )
+    {
+    throw std::runtime_error("Input matrix is null");
+    }
+
+  DataType *buffer =  matrix->data_block();
+  //ComponentType *buffer =  const_cast < ComponentType *> (reinterpret_cast< const ComponentType* > ( image->GetBufferPointer() ) );
+  void * matrixBuffer = (void *)( buffer );
+
+  // Computing the length of data
+  Py_ssize_t len = matrix->size();
+  len *= elementSize;
+
+  res = PyBuffer_FillInfo(&pyBuffer, NULL, (void*)matrixBuffer, len, 0, PyBUF_CONTIG);
+  memoryView = PyMemoryView_FromBuffer(&pyBuffer);
+
+  PyBuffer_Release(&pyBuffer);
+
+  return memoryView;
+}
+
+template<class TElement>
+const typename PyVnl<TElement>::MatrixType
+PyVnl<TElement>
+::_GetVnlMatrixViewFromArray( PyObject *arr, PyObject *shape)
+{
+  PyObject *                  obj           = NULL;
+  PyObject *                  shapeseq      = NULL;
+  PyObject *                  item          = NULL;
+
+  Py_ssize_t                  bufferLength;
+  Py_buffer                   pyBuffer;
+  memset(&pyBuffer, 0, sizeof(Py_buffer));
+
+  size_t numberOfElements = 1;
+
+  const void *                buffer;
+
+  unsigned int                dimension     = 0;
+
+  size_t                      elementSize   = sizeof(DataType);
+  size_t                      len           = 1;
+  unsigned int                size[2];
+
+  if(PyObject_GetBuffer(arr, &pyBuffer, PyBUF_CONTIG) == -1)
+    {
+    PyErr_SetString( PyExc_RuntimeError, "Cannot get an instance of NumPy array." );
+    PyBuffer_Release(&pyBuffer);
+    return MatrixType();
+    }
+  else
+    {
+    bufferLength = pyBuffer.len;
+    buffer = pyBuffer.buf;
+    }
+
+  obj        = shape;
+  shapeseq   = PySequence_Fast(obj, "expected sequence");
+  dimension  = PySequence_Size(obj);
+
+  for( unsigned int i = 0; i < 2; ++i )
+    {
+    item = PySequence_Fast_GET_ITEM(shapeseq,i);
+    size[i] = (unsigned int)PyLong_AsLong(item);
+    numberOfElements *= size[i];
+    }
+
+  len = numberOfElements*elementSize;
+  if ( bufferLength != len )
+    {
+    PyErr_SetString( PyExc_RuntimeError, "Size mismatch of matrix and Buffer." );
+    PyBuffer_Release(&pyBuffer);
+    return MatrixType();
+    }
+
+  DataType * data = (DataType *)buffer;
+  MatrixType output(data, size[0], size[1]);
+  PyBuffer_Release(&pyBuffer);
+
+  return output;
+}
+
+
+} // namespace itk
+
+#endif
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