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/*=========================================================================
*
* 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.
*
*=========================================================================*/
#include "itkTimeVaryingVelocityFieldIntegrationImageFilter.h"
int itkTimeVaryingVelocityFieldIntegrationImageFilterTest( int, char* [] )
{
typedef itk::Vector<double, 3> VectorType;
typedef itk::Image<VectorType, 3> DisplacementFieldType;
typedef itk::Image<VectorType, 4> TimeVaryingVelocityFieldType;
TimeVaryingVelocityFieldType::PointType origin;
origin.Fill( 0.0 );
TimeVaryingVelocityFieldType::SpacingType spacing;
spacing.Fill( 2.0 );
TimeVaryingVelocityFieldType::SizeType size;
size.Fill( 25 );
VectorType displacement1;
displacement1.Fill( 0.1 );
TimeVaryingVelocityFieldType::Pointer timeVaryingVelocityField =
TimeVaryingVelocityFieldType::New();
timeVaryingVelocityField->SetOrigin( origin );
timeVaryingVelocityField->SetSpacing( spacing );
timeVaryingVelocityField->SetRegions( size );
timeVaryingVelocityField->Allocate();
timeVaryingVelocityField->FillBuffer( displacement1 );
typedef itk::TimeVaryingVelocityFieldIntegrationImageFilter
<TimeVaryingVelocityFieldType, DisplacementFieldType> IntegratorType;
IntegratorType::Pointer integrator = IntegratorType::New();
integrator->SetInput( timeVaryingVelocityField );
integrator->SetLowerTimeBound( 0.3 );
integrator->SetUpperTimeBound( 0.75 );
integrator->SetNumberOfIntegrationSteps( 10 );
integrator->Update();
integrator->Print( std::cout, 3 );
DisplacementFieldType::IndexType index;
index.Fill( 0 );
VectorType displacement;
IntegratorType::Pointer inverseIntegrator = IntegratorType::New();
inverseIntegrator->SetInput( timeVaryingVelocityField );
inverseIntegrator->SetLowerTimeBound( 1.0 );
inverseIntegrator->SetUpperTimeBound( 0.0 );
inverseIntegrator->SetNumberOfIntegrationSteps( 10 );
inverseIntegrator->Update();
// This integration should result in a constant image of value
// -( 0.1 * 1.0 - ( 0.1 * 0.0 ) ) = -0.1 with ~epsilon deviation
// due to numerical computations
const DisplacementFieldType * inverseField = inverseIntegrator->GetOutput();
displacement = inverseField->GetPixel( index );
std::cout << "Estimated inverse displacement vector: " << displacement << std::endl;
if( itk::Math::abs( displacement[0] + 0.101852 ) > 0.01 )
{
std::cerr << "Failed to produce the correct inverse integration." << std::endl;
return EXIT_FAILURE;
}
inverseIntegrator->Print( std::cout, 3 );
std::cout << inverseIntegrator->GetNameOfClass() << std::endl;
// This integration should result in a constant image of value
// 0.75 * 0.1 - 0.3 * 0.1 = 0.045 with ~epsilon deviation
// due to numerical computations
const DisplacementFieldType * displacementField = integrator->GetOutput();
displacement = displacementField->GetPixel( index );
std::cout << "Estimated forward displacement vector: " << displacement << std::endl;
if( itk::Math::abs( displacement[0] - 0.045 ) > 0.0001 )
{
std::cerr << "Failed to produce the correct forward integration." << std::endl;
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}
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