void FibersFromPlanarFiguresFilter::GeneratePoints() { Statistics::MersenneTwisterRandomVariateGenerator::Pointer randGen = Statistics::MersenneTwisterRandomVariateGenerator::New(); randGen->SetSeed((unsigned int)0); m_2DPoints.clear(); unsigned int count = 0; while (count < m_Parameters.m_Density) { mitk::Vector2D p; switch (m_Parameters.m_Distribution) { case FiberGenerationParameters::DISTRIBUTE_GAUSSIAN: p[0] = randGen->GetNormalVariate(0, m_Parameters.m_Variance); p[1] = randGen->GetNormalVariate(0, m_Parameters.m_Variance); break; default: p[0] = randGen->GetUniformVariate(-1, 1); p[1] = randGen->GetUniformVariate(-1, 1); } if (sqrt(p[0]*p[0]+p[1]*p[1]) <= 1) { m_2DPoints.push_back(p); count++; } } }
void GibbsTrackingFilter< ItkQBallImageType > ::EstimateParticleWeight() { MITK_INFO << "GibbsTrackingFilter: estimating particle weight"; float minSpacing; if(m_QBallImage->GetSpacing()[0]<m_QBallImage->GetSpacing()[1] && m_QBallImage->GetSpacing()[0]<m_QBallImage->GetSpacing()[2]) minSpacing = m_QBallImage->GetSpacing()[0]; else if (m_QBallImage->GetSpacing()[1] < m_QBallImage->GetSpacing()[2]) minSpacing = m_QBallImage->GetSpacing()[1]; else minSpacing = m_QBallImage->GetSpacing()[2]; float m_ParticleLength = 1.5*minSpacing; float m_ParticleWidth = 0.5*minSpacing; // seed random generators Statistics::MersenneTwisterRandomVariateGenerator::Pointer randGen = Statistics::MersenneTwisterRandomVariateGenerator::New(); if (m_RandomSeed>-1) randGen->SetSeed(m_RandomSeed); else randGen->SetSeed(); // instantiate all necessary components SphereInterpolator* interpolator = new SphereInterpolator(m_LutPath); // handle lookup table not found cases if( !interpolator->IsInValidState() ) { m_IsInValidState = false; m_AbortTracking = true; m_BuildFibers = false; mitkThrow() << "Unable to load lookup tables."; } ParticleGrid* particleGrid = new ParticleGrid(m_MaskImage, m_ParticleLength, m_ParticleGridCellCapacity); GibbsEnergyComputer* encomp = new GibbsEnergyComputer(m_QBallImage, m_MaskImage, particleGrid, interpolator, randGen); // EnergyComputer* encomp = new EnergyComputer(m_QBallImage, m_MaskImage, particleGrid, interpolator, randGen); MetropolisHastingsSampler* sampler = new MetropolisHastingsSampler(particleGrid, encomp, randGen, m_CurvatureThreshold); float alpha = log(m_EndTemperature/m_StartTemperature); m_ParticleWeight = 0.01; int ppv = 0; // main loop int neededParts = 3000; while (ppv<neededParts) { if (ppv<1000) m_ParticleWeight /= 2; else m_ParticleWeight = ppv*m_ParticleWeight/neededParts; encomp->SetParameters(m_ParticleWeight,m_ParticleWidth,m_ConnectionPotential*m_ParticleLength*m_ParticleLength,m_CurvatureThreshold,m_InexBalance,m_ParticlePotential); for( int step = 0; step < 10; step++ ) { // update temperatur for simulated annealing process float temperature = m_StartTemperature * exp(alpha*(((1.0)*step)/((1.0)*10))); sampler->SetTemperature(temperature); for (unsigned long i=0; i<10000; i++) sampler->MakeProposal(); } ppv = particleGrid->m_NumParticles; particleGrid->ResetGrid(); } delete sampler; delete encomp; delete particleGrid; delete interpolator; MITK_INFO << "GibbsTrackingFilter: finished estimating particle weight"; }
void GibbsTrackingFilter< ItkQBallImageType >::GenerateData() { TimeProbe preClock; preClock.Start(); // check if input is qball or tensor image and generate qball if necessary if (m_QBallImage.IsNull() && m_TensorImage.IsNotNull()) { TensorImageToQBallImageFilter<float,float>::Pointer filter = TensorImageToQBallImageFilter<float,float>::New(); filter->SetInput( m_TensorImage ); filter->Update(); m_QBallImage = filter->GetOutput(); } else if (m_DuplicateImage) // generate local working copy of QBall image (if not disabled) { typedef itk::ImageDuplicator< ItkQBallImageType > DuplicateFilterType; typename DuplicateFilterType::Pointer duplicator = DuplicateFilterType::New(); duplicator->SetInputImage( m_QBallImage ); duplicator->Update(); m_QBallImage = duplicator->GetOutput(); } // perform mean subtraction on odfs typedef ImageRegionIterator< ItkQBallImageType > InputIteratorType; InputIteratorType it(m_QBallImage, m_QBallImage->GetLargestPossibleRegion() ); it.GoToBegin(); while (!it.IsAtEnd()) { itk::OrientationDistributionFunction<float, QBALL_ODFSIZE> odf(it.Get().GetDataPointer()); float mean = odf.GetMeanValue(); odf -= mean; it.Set(odf.GetDataPointer()); ++it; } // check if mask image is given if it needs resampling PrepareMaskImage(); // load parameter file LoadParameters(); // prepare parameters float minSpacing; if(m_QBallImage->GetSpacing()[0]<m_QBallImage->GetSpacing()[1] && m_QBallImage->GetSpacing()[0]<m_QBallImage->GetSpacing()[2]) minSpacing = m_QBallImage->GetSpacing()[0]; else if (m_QBallImage->GetSpacing()[1] < m_QBallImage->GetSpacing()[2]) minSpacing = m_QBallImage->GetSpacing()[1]; else minSpacing = m_QBallImage->GetSpacing()[2]; if(m_ParticleLength == 0) m_ParticleLength = 1.5*minSpacing; if(m_ParticleWidth == 0) m_ParticleWidth = 0.5*minSpacing; if(m_ParticleWeight == 0) EstimateParticleWeight(); float alpha = log(m_EndTemperature/m_StartTemperature); m_Steps = m_Iterations/10000; if (m_Steps<10) m_Steps = 10; if (m_Steps>m_Iterations) { MITK_INFO << "GibbsTrackingFilter: not enough iterations!"; m_AbortTracking = true; } if (m_CurvatureThreshold < mitk::eps) m_CurvatureThreshold = 0; unsigned long singleIts = (unsigned long)((1.0*m_Iterations) / (1.0*m_Steps)); // seed random generators Statistics::MersenneTwisterRandomVariateGenerator::Pointer randGen = Statistics::MersenneTwisterRandomVariateGenerator::New(); if (m_RandomSeed>-1) randGen->SetSeed(m_RandomSeed); else randGen->SetSeed(); // load sphere interpolator to evaluate the ODFs SphereInterpolator* interpolator = new SphereInterpolator(m_LutPath); // handle lookup table not found cases if( !interpolator->IsInValidState() ) { m_IsInValidState = false; m_AbortTracking = true; m_BuildFibers = false; mitkThrow() << "Unable to load lookup tables."; } // initialize the actual tracking components (ParticleGrid, Metropolis Hastings Sampler and Energy Computer) ParticleGrid* particleGrid; GibbsEnergyComputer* encomp; MetropolisHastingsSampler* sampler; try{ particleGrid = new ParticleGrid(m_MaskImage, m_ParticleLength, m_ParticleGridCellCapacity); encomp = new GibbsEnergyComputer(m_QBallImage, m_MaskImage, particleGrid, interpolator, randGen); encomp->SetParameters(m_ParticleWeight,m_ParticleWidth,m_ConnectionPotential*m_ParticleLength*m_ParticleLength,m_CurvatureThreshold,m_InexBalance,m_ParticlePotential); sampler = new MetropolisHastingsSampler(particleGrid, encomp, randGen, m_CurvatureThreshold); } catch(...) { MITK_ERROR << "Particle grid allocation failed. Not enough memory? Try to increase the particle length."; m_IsInValidState = false; m_AbortTracking = true; m_BuildFibers = false; return; } MITK_INFO << "----------------------------------------"; MITK_INFO << "Iterations: " << m_Iterations; MITK_INFO << "Steps: " << m_Steps; MITK_INFO << "Particle length: " << m_ParticleLength; MITK_INFO << "Particle width: " << m_ParticleWidth; MITK_INFO << "Particle weight: " << m_ParticleWeight; MITK_INFO << "Start temperature: " << m_StartTemperature; MITK_INFO << "End temperature: " << m_EndTemperature; MITK_INFO << "In/Ex balance: " << m_InexBalance; MITK_INFO << "Min. fiber length: " << m_MinFiberLength; MITK_INFO << "Curvature threshold: " << m_CurvatureThreshold; MITK_INFO << "Random seed: " << m_RandomSeed; MITK_INFO << "----------------------------------------"; // main loop preClock.Stop(); TimeProbe clock; clock.Start(); m_NumAcceptedFibers = 0; unsigned long counter = 1; boost::progress_display disp(m_Steps*singleIts); if (!m_AbortTracking) for( m_CurrentStep = 1; m_CurrentStep <= m_Steps; m_CurrentStep++ ) { // update temperatur for simulated annealing process float temperature = m_StartTemperature * exp(alpha*(((1.0)*m_CurrentStep)/((1.0)*m_Steps))); sampler->SetTemperature(temperature); for (unsigned long i=0; i<singleIts; i++) { ++disp; if (m_AbortTracking) break; sampler->MakeProposal(); if (m_BuildFibers || (i==singleIts-1 && m_CurrentStep==m_Steps)) { m_ProposalAcceptance = (float)sampler->GetNumAcceptedProposals()/counter; m_NumParticles = particleGrid->m_NumParticles; m_NumConnections = particleGrid->m_NumConnections; FiberBuilder fiberBuilder(particleGrid, m_MaskImage); m_FiberPolyData = fiberBuilder.iterate(m_MinFiberLength); m_NumAcceptedFibers = m_FiberPolyData->GetNumberOfLines(); m_BuildFibers = false; } counter++; } m_ProposalAcceptance = (float)sampler->GetNumAcceptedProposals()/counter; m_NumParticles = particleGrid->m_NumParticles; m_NumConnections = particleGrid->m_NumConnections; if (m_AbortTracking) break; } if (m_AbortTracking) { FiberBuilder fiberBuilder(particleGrid, m_MaskImage); m_FiberPolyData = fiberBuilder.iterate(m_MinFiberLength); m_NumAcceptedFibers = m_FiberPolyData->GetNumberOfLines(); } clock.Stop(); delete sampler; delete encomp; delete interpolator; delete particleGrid; m_AbortTracking = true; m_BuildFibers = false; int h = clock.GetTotal()/3600; int m = ((int)clock.GetTotal()%3600)/60; int s = (int)clock.GetTotal()%60; MITK_INFO << "GibbsTrackingFilter: finished gibbs tracking in " << h << "h, " << m << "m and " << s << "s"; m = (int)preClock.GetTotal()/60; s = (int)preClock.GetTotal()%60; MITK_INFO << "GibbsTrackingFilter: preparation of the data took " << m << "m and " << s << "s"; MITK_INFO << "GibbsTrackingFilter: " << m_NumAcceptedFibers << " fibers accepted"; // sampler->PrintProposalTimes(); SaveParameters(); }