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/*=========================================================================
*
* Copyright UMC Utrecht and contributors
*
* 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 _itkUpsampleBSplineParametersFilter_hxx
#define _itkUpsampleBSplineParametersFilter_hxx
#include "itkUpsampleBSplineParametersFilter.h"
#include "itkBSplineResampleImageFunction.h"
#include "itkBSplineDecompositionImageFilter.h"
#include "itkResampleImageFilter.h"
namespace itk
{
/**
* ******************* Constructor *******************
*/
template <typename TArray, typename TImage>
UpsampleBSplineParametersFilter<TArray, TImage>::UpsampleBSplineParametersFilter()
{
this->m_BSplineOrder = 3;
// Initialize grid settings.
this->m_CurrentGridOrigin.Fill(0.0);
this->m_CurrentGridSpacing.Fill(0.0);
this->m_CurrentGridDirection.Fill(0.0);
this->m_RequiredGridOrigin.Fill(0.0);
this->m_RequiredGridSpacing.Fill(0.0);
this->m_RequiredGridDirection.Fill(0.0);
} // end Constructor()
/**
* ******************* UpsampleParameters *******************
*/
template <typename TArray, typename TImage>
void
UpsampleBSplineParametersFilter<TArray, TImage>::UpsampleParameters(const ArrayType & parameters_in,
ArrayType & parameters_out)
{
/** Determine if upsampling is required. */
if (!this->DoUpsampling())
{
parameters_out = parameters_in; // \todo: hard copy, can be avoided
return;
}
/** Typedefs. */
using UpsampleFilterType = itk::ResampleImageFilter<ImageType, ImageType>;
using CoefficientUpsampleFunctionType = itk::BSplineResampleImageFunction<ImageType, ValueType>;
using DecompositionFilterType = itk::BSplineDecompositionImageFilter<ImageType, ImageType>;
/** Get the number of parameters. */
const unsigned int currentNumberOfPixels = this->m_CurrentGridRegion.GetNumberOfPixels();
const unsigned int requiredNumberOfPixels = this->m_RequiredGridRegion.GetNumberOfPixels();
/** Create the new vector of output parameters, with the correct size. */
parameters_out.SetSize(requiredNumberOfPixels * Dimension);
/** Get the pointer to the data of the input parameters. */
auto * inputDataPointer = const_cast<PixelType *>(parameters_in.data_block());
auto * outputDataPointer = const_cast<PixelType *>(parameters_out.data_block());
/** The input parameters are represented as a coefficient image. */
ImagePointer coeffs_in = ImageType::New();
coeffs_in->SetOrigin(this->m_CurrentGridOrigin);
coeffs_in->SetSpacing(this->m_CurrentGridSpacing);
coeffs_in->SetDirection(this->m_CurrentGridDirection);
coeffs_in->SetRegions(this->m_CurrentGridRegion);
/** Loop over dimension: each direction is upsampled separately. */
for (unsigned int j = 0; j < Dimension; ++j)
{
/** Fill the coefficient image with parameter data. */
coeffs_in->GetPixelContainer()->SetImportPointer(inputDataPointer, currentNumberOfPixels);
inputDataPointer += currentNumberOfPixels;
/** Set the coefficient image as the input of the upsampler filter.
* The upsampler samples the deformation field at the locations
* of the new control points, given the current coefficients
* (note: it does not just interpolate the coefficient image,
* which would be wrong). The B-spline coefficients that
* describe the resulting image are computed by the
* decomposition filter.
*
* This code is derived from the itk-example DeformableRegistration6.cxx.
*/
auto upsampler = UpsampleFilterType::New();
auto coeffUpsampleFunction = CoefficientUpsampleFunctionType::New();
auto decompositionFilter = DecompositionFilterType::New();
/** Setup the upsampler. */
upsampler->SetInterpolator(coeffUpsampleFunction);
upsampler->SetSize(this->m_RequiredGridRegion.GetSize());
upsampler->SetOutputStartIndex(this->m_RequiredGridRegion.GetIndex());
upsampler->SetOutputSpacing(this->m_RequiredGridSpacing);
upsampler->SetOutputOrigin(this->m_RequiredGridOrigin);
upsampler->SetOutputDirection(this->m_RequiredGridDirection);
upsampler->SetInput(coeffs_in);
/** Setup the decomposition filter. */
decompositionFilter->SetSplineOrder(this->m_BSplineOrder);
decompositionFilter->SetInput(upsampler->GetOutput());
/** Do the upsampling. */
try
{
decompositionFilter->UpdateLargestPossibleRegion();
// \todo: the decomposition filter could be multi-threaded
// by deriving it from the RecursiveSeparableImageFilter,
// similar to the SmoothingRecursiveGaussianImageFilter.
}
catch (itk::ExceptionObject & excp)
{
/** Add information to the exception. */
excp.SetLocation("UpsampleBSplineParametersFilter - UpsampleParameters()");
std::string err_str = excp.GetDescription();
err_str += "\nError occurred while using decompositionFilter.\n";
excp.SetDescription(err_str);
/** Pass the exception to an higher level. */
throw;
}
/** Get a pointer to the upsampled coefficient image. */
const PixelType * coeffs_out = decompositionFilter->GetOutput()->GetBufferPointer();
/** Copy the contents of coeffs_out in a ParametersType array. */
std::copy(coeffs_out, coeffs_out + requiredNumberOfPixels, outputDataPointer + requiredNumberOfPixels * j);
} // end for dimension loop
} // end UpsampleParameters()
/**
* ******************* DoUpsampling *******************
*/
template <typename TArray, typename TImage>
bool
UpsampleBSplineParametersFilter<TArray, TImage>::DoUpsampling()
{
bool ret = (this->m_CurrentGridOrigin != this->m_RequiredGridOrigin);
ret |= (this->m_CurrentGridSpacing != this->m_RequiredGridSpacing);
ret |= (this->m_CurrentGridDirection != this->m_RequiredGridDirection);
ret |= (this->m_CurrentGridRegion != this->m_RequiredGridRegion);
return ret;
} // end DoUpsampling()
/**
* ******************* PrintSelf *******************
*/
template <typename TArray, typename TImage>
void
UpsampleBSplineParametersFilter<TArray, TImage>::PrintSelf(std::ostream & os, Indent indent) const
{
this->Superclass::PrintSelf(os, indent);
os << indent << "CurrentGridOrigin: " << this->m_CurrentGridOrigin << std::endl;
os << indent << "CurrentGridSpacing: " << this->m_CurrentGridSpacing << std::endl;
os << indent << "CurrentGridDirection: " << this->m_CurrentGridDirection << std::endl;
os << indent << "CurrentGridRegion: " << this->m_CurrentGridRegion << std::endl;
os << indent << "RequiredGridOrigin: " << this->m_RequiredGridOrigin << std::endl;
os << indent << "RequiredGridSpacing: " << this->m_RequiredGridSpacing << std::endl;
os << indent << "RequiredGridDirection: " << this->m_RequiredGridDirection << std::endl;
os << indent << "RequiredGridRegion: " << this->m_RequiredGridRegion << std::endl;
os << indent << "BSplineOrder: " << this->m_BSplineOrder << std::endl;
} // end PrintSelf()
} // end namespace itk
#endif
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