Function TestRandomPixelAccess

Modules/Core/test/mitkImageTest.cpp:62–127

template <class T>
void TestRandomPixelAccess(const mitk::PixelType /*ptype*/,
                           mitk::Image::Pointer image,
                           mitk::Point3D &point,
                           mitk::ScalarType &value)
{
  // generate a random point in world coordinates
  mitk::Point3D xMax, yMax, zMax, xMaxIndex, yMaxIndex, zMaxIndex;
  xMaxIndex.Fill(0.0f);
  yMaxIndex.Fill(0.0f);
  zMaxIndex.Fill(0.0f);
  xMaxIndex[0] = image->GetLargestPossibleRegion().GetSize()[0];
  yMaxIndex[1] = image->GetLargestPossibleRegion().GetSize()[1];
  zMaxIndex[2] = image->GetLargestPossibleRegion().GetSize()[2];
  image->GetGeometry()->IndexToWorld(xMaxIndex, xMax);
  image->GetGeometry()->IndexToWorld(yMaxIndex, yMax);
  image->GetGeometry()->IndexToWorld(zMaxIndex, zMax);
  MITK_INFO << "Origin " << image->GetGeometry()->GetOrigin()[0] << " " << image->GetGeometry()->GetOrigin()[1] << " "
            << image->GetGeometry()->GetOrigin()[2] << "";
  MITK_INFO << "MaxExtend " << xMax[0] << " " << yMax[1] << " " << zMax[2] << "";

  itk::Statistics::MersenneTwisterRandomVariateGenerator::Pointer randomGenerator =
    itk::Statistics::MersenneTwisterRandomVariateGenerator::New();
  randomGenerator->Initialize(std::rand()); // initialize with random value, to get sensible random points for the image
  point[0] = randomGenerator->GetUniformVariate(image->GetGeometry()->GetOrigin()[0], xMax[0]);
  point[1] = randomGenerator->GetUniformVariate(image->GetGeometry()->GetOrigin()[1], yMax[1]);
  point[2] = randomGenerator->GetUniformVariate(image->GetGeometry()->GetOrigin()[2], zMax[2]);
  MITK_INFO << "RandomPoint " << point[0] << " " << point[1] << " " << point[2] << "";

  // test values and max/min
  mitk::ScalarType imageMin = image->GetStatistics()->GetScalarValueMin();
  mitk::ScalarType imageMax = image->GetStatistics()->GetScalarValueMax();

  // test accessing PixelValue with coordinate leading to a negative index
  const mitk::Point3D geom_origin = image->GetGeometry()->GetOrigin();
  const mitk::Point3D geom_center = image->GetGeometry()->GetCenter();

  // shift position from origin outside of the image ( in the opposite direction to [center-origin] vector which points
  // in the inside)
  mitk::Point3D position = geom_origin + (geom_origin - geom_center);

  MITK_INFO << "Testing access outside of the image";
  unsigned int dim = image->GetDimension();
  if (dim == 3 || dim == 4)
  {
    mitk::ImagePixelReadAccessor<T, 3> imAccess3(image, image->GetVolumeData(0));

    // Comparison ?>=0 not needed since all position[i] and timestep are unsigned int
    // (position[0]>=0 && position[1] >=0 && position[2]>=0 && timestep>=0)
    // bug-11978 : we still need to catch index with negative values
    if (point[0] < 0 || point[1] < 0 || point[2] < 0)
    {
      MITK_WARN << "Given position (" << point << ") is out of image range, returning 0.";
    }
    else
    {
      value = static_cast<mitk::ScalarType>(imAccess3.GetPixelByWorldCoordinates(point));
      MITK_TEST_CONDITION((value >= imageMin && value <= imageMax), "Value returned is between max/min");
    }