spectrogram.cpp

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//=============================================================================================================
 
//=============================================================================================================
// INCLUDES
//=============================================================================================================
 
#include "spectrogram.h"
 
//=============================================================================================================
// EIGEN INCLUDES
//=============================================================================================================
 
#include <Eigen/SparseCore>
#include <unsupported/Eigen/FFT>
 
//=============================================================================================================
// QT INCLUDES
//=============================================================================================================
 
#include <QDebug>
#include <QElapsedTimer>
#include <QThread>
#include <QtConcurrent>
 
//=============================================================================================================
// USED NAMESPACES
//=============================================================================================================
 
using namespace UTILSLIB;
using namespace Eigen;
 
//=============================================================================================================
// DEFINE MEMBER METHODS
//=============================================================================================================
 
MatrixXd Spectrogram::makeSpectrogram(VectorXd signal, qint32 windowSize = 0)
{
    //QElapsedTimer timer;
    //timer.start();
 
    signal.array() -= signal.mean();
    QList<SpectogramInputData> lData;
    int iThreadSize = QThread::idealThreadCount()*2;
    int iStepsSize = signal.rows()/iThreadSize;
    int iResidual = signal.rows()%iThreadSize;
 
    SpectogramInputData dataTemp;
    dataTemp.vecInputData = signal;
    dataTemp.window_size = windowSize;
    if(dataTemp.window_size == 0) {
        dataTemp.window_size = signal.rows()/15;
    }
 
    for (int i = 0; i < iThreadSize; ++i) {
        dataTemp.iRangeLow = i*iStepsSize;
        dataTemp.iRangeHigh = i*iStepsSize+iStepsSize;
        lData.append(dataTemp);
    }
 
    dataTemp.iRangeLow = iThreadSize*iStepsSize;
    dataTemp.iRangeHigh = iThreadSize*iStepsSize+iResidual;
    lData.append(dataTemp);
 
    QFuture<MatrixXd> resultMat = QtConcurrent::mappedReduced(lData,
                                                              compute,
                                                              reduce);
    resultMat.waitForFinished();
 
    //qDebug() << "Spectrogram::make_spectrogram - timer.elapsed()" << timer.elapsed();
    return resultMat.result();
}
 
//=============================================================================================================
 
VectorXd Spectrogram::gaussWindow(qint32 sample_count, qreal scale, quint32 translation)
{
    VectorXd gauss = VectorXd::Zero(sample_count);
 
    for(qint32 n = 0; n < sample_count; n++)
    {
        qreal t = (qreal(n) - translation) / scale;
        gauss[n] = exp(-3.14 * pow(t, 2))*pow(sqrt(scale),(-1))*pow(qreal(2),(0.25));
    }
 
    return gauss;
}
 
//=============================================================================================================
 
MatrixXd Spectrogram::compute(const SpectogramInputData& inputData)
{
    #ifdef EIGEN_FFTW_DEFAULT
        fftw_make_planner_thread_safe();
    #endif
 
    Eigen::FFT<double> fft;
    MatrixXd tf_matrix = MatrixXd::Zero(inputData.vecInputData.rows()/2, inputData.vecInputData.rows());
    VectorXd envelope, windowed_sig, real_coeffs;
    VectorXcd fft_win_sig;
    qint32 window_size = inputData.window_size;
 
    for(quint32 translate = inputData.iRangeLow; translate < inputData.iRangeHigh; translate++) {
        envelope = gaussWindow(inputData.vecInputData.rows(), window_size, translate);
 
        windowed_sig = VectorXd::Zero(inputData.vecInputData.rows());
        fft_win_sig = VectorXcd::Zero(inputData.vecInputData.rows());
 
        windowed_sig = inputData.vecInputData.array() * envelope.array();\
 
        fft.fwd(fft_win_sig, windowed_sig);
 
        real_coeffs = fft_win_sig.segment(0,inputData.vecInputData.rows()/2).array().abs2();
 
        tf_matrix.col(translate) = real_coeffs;
    }
 
    return tf_matrix;
}
 
//=============================================================================================================
 
void Spectrogram::reduce(MatrixXd &resultData,
                         const MatrixXd &data)
{
    if(resultData.size() == 0) {
        resultData = data;
    } else {
        resultData += data;
    }
}