RowVectorXd FilterData::applyFFTFilter(const RowVectorXd& data, bool keepOverhead, CompensateEdgeEffects compensateEdgeEffects) const
{
#ifdef EIGEN_FFTW_DEFAULT
fftw_make_planner_thread_safe();
#endif
if(data.cols()<m_dCoeffA.cols() && compensateEdgeEffects==MirrorData) {
qDebug()<<QString("Error in FilterData: Number of filter taps(%1) bigger then data size(%2). Not enough data to perform mirroring!").arg(m_dCoeffA.cols()).arg(data.cols());
return data;
}
// std::cout<<"m_iFFTlength: "<<m_iFFTlength<<std::endl;
// std::cout<<"2*m_dCoeffA.cols() + data.cols(): "<<2*m_dCoeffA.cols() + data.cols()<<std::endl;
if(2*m_dCoeffA.cols() + data.cols()>m_iFFTlength) {
qDebug()<<"Error in FilterData: Number of mirroring/zeropadding size plus data size is bigger then fft length!";
return data;
}
//Do zero padding or mirroring depending on user input
RowVectorXd t_dataZeroPad = RowVectorXd::Zero(m_iFFTlength);
switch(compensateEdgeEffects) {
case MirrorData:
t_dataZeroPad.head(m_dCoeffA.cols()) = data.head(m_dCoeffA.cols()).reverse(); //front
t_dataZeroPad.segment(m_dCoeffA.cols(), data.cols()) = data; //middle
t_dataZeroPad.tail(m_dCoeffA.cols()) = data.tail(m_dCoeffA.cols()).reverse(); //back
break;
case ZeroPad:
t_dataZeroPad.head(data.cols()) = data;
break;
default:
t_dataZeroPad.head(data.cols()) = data;
break;
}
//generate fft object
Eigen::FFT<double> fft;
fft.SetFlag(fft.HalfSpectrum);
//fft-transform data sequence
RowVectorXcd t_freqData;
fft.fwd(t_freqData,t_dataZeroPad);
//perform frequency-domain filtering
RowVectorXcd t_filteredFreq = m_dFFTCoeffA.array()*t_freqData.array();
//inverse-FFT
RowVectorXd t_filteredTime;
fft.inv(t_filteredTime,t_filteredFreq);
//Return filtered data
if(!keepOverhead)
return t_filteredTime.segment(m_dCoeffA.cols()/2, data.cols());
return t_filteredTime.head(data.cols()+m_dCoeffA.cols());
}
RowVectorXd FilterData::applyConvFilter(const RowVectorXd& data, bool keepOverhead, CompensateEdgeEffects compensateEdgeEffects) const
{
if(data.cols()<m_dCoeffA.cols() && compensateEdgeEffects==MirrorData){
qDebug()<<QString("Error in FilterData: Number of filter taps(%1) bigger then data size(%2). Not enough data to perform mirroring!").arg(m_dCoeffA.cols()).arg(data.cols());
return data;
}
//Do zero padding or mirroring depending on user input
RowVectorXd t_dataZeroPad = RowVectorXd::Zero(2*m_dCoeffA.cols() + data.cols());
RowVectorXd t_filteredTime = RowVectorXd::Zero(2*m_dCoeffA.cols() + data.cols());
switch(compensateEdgeEffects) {
case MirrorData:
t_dataZeroPad.head(m_dCoeffA.cols()) = data.head(m_dCoeffA.cols()).reverse(); //front
t_dataZeroPad.segment(m_dCoeffA.cols(), data.cols()) = data; //middle
t_dataZeroPad.tail(m_dCoeffA.cols()) = data.tail(m_dCoeffA.cols()).reverse(); //back
break;
case ZeroPad:
t_dataZeroPad.segment(m_dCoeffA.cols(), data.cols()) = data;
break;
default:
t_dataZeroPad.segment(m_dCoeffA.cols(), data.cols()) = data;
break;
}
//Do the convolution
for(int i=m_dCoeffA.cols(); i<t_filteredTime.cols(); i++)
t_filteredTime(i-m_dCoeffA.cols()) = t_dataZeroPad.segment(i-m_dCoeffA.cols(),m_dCoeffA.cols()) * m_dCoeffA.transpose();
//Return filtered data
if(!keepOverhead)
return t_filteredTime.segment(m_dCoeffA.cols()/2, data.cols());
return t_filteredTime.head(data.cols()+m_dCoeffA.cols());
}
