animaT2EPGRelaxometryCostFunction.cxx

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#include "animaT2EPGRelaxometryCostFunction.h"
#include <animaEPGSignalSimulator.h>

namespace anima
{
    
T2EPGRelaxometryCostFunction::MeasureType
T2EPGRelaxometryCostFunction::GetValue(const ParametersType & parameters) const
{
    m_T2Value = parameters[0];
    m_B1Value = parameters[1];

    double residualValue = 0;
    unsigned int numT2Signals = m_T2RelaxometrySignals.size();

    anima::EPGSignalSimulator t2SignalSimulator;
    t2SignalSimulator.SetNumberOfEchoes(m_T2RelaxometrySignals.size());
    t2SignalSimulator.SetEchoSpacing(m_T2EchoSpacing);
    t2SignalSimulator.SetExcitationFlipAngle(m_T2ExcitationFlipAngle);

    anima::EPGSignalSimulator::RealVectorType simulatedT2Values = t2SignalSimulator.GetValue(m_T1Value,m_T2Value,m_B1Value * m_T2FlipAngles[0],1.0);

    double sumSignals = 0;
    double sumSimulatedSignals = 0;
    for (unsigned int i = 0;i < numT2Signals;++i)
    {
        sumSignals += m_T2RelaxometrySignals[i];
        sumSimulatedSignals += simulatedT2Values[i];
    }

    m_M0Value = sumSignals / sumSimulatedSignals;

    for (unsigned int i = 0;i < numT2Signals;++i)
        residualValue += (m_M0Value * simulatedT2Values[i] - m_T2RelaxometrySignals[i]) * (m_M0Value * simulatedT2Values[i] - m_T2RelaxometrySignals[i]);

    return residualValue;
}
    
} // end namespace anima