annotate dsp/signalconditioning/DFProcess.cpp @ 96:88f3cfcff55f

A threshold (delta) is added in the peak picking parameters structure (PPickParams). It is used as an offset when computing the smoothed detection function. A constructor for the structure PPickParams is also added to set the parameters to 0 when a structure instance is created. Hence programmes using the peak picking parameter structure and which do not set the delta parameter (e.g. QM Vamp note onset detector) won't be affected by the modifications.

Functions modified:
- dsp/onsets/PeakPicking.cpp
- dsp/onsets/PeakPicking.h
- dsp/signalconditioning/DFProcess.cpp
- dsp/signalconditioning/DFProcess.h

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/*
    QM DSP Library

    Centre for Digital Music, Queen Mary, University of London.
    This file 2005-2006 Christian Landone.

    Modifications:

    - delta threshold
    Description: add delta threshold used as offset in the smoothed
    detection function
    Author: Mathieu Barthet
    Date: June 2010

    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License as
    published by the Free Software Foundation; either version 2 of the
    License, or (at your option) any later version.  See the file
    COPYING included with this distribution for more information.
*/

#include "DFProcess.h"
#include "maths/MathUtilities.h"

#include <cstring>

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

DFProcess::DFProcess( DFProcConfig Config )
{
    filtSrc = NULL;
    filtDst = NULL;	
    m_filtScratchIn = NULL;
    m_filtScratchOut = NULL;

    m_FFOrd = 0;

    initialise( Config );
}

DFProcess::~DFProcess()
{
    deInitialise();
}

void DFProcess::initialise( DFProcConfig Config )
{
    m_length = Config.length;
    m_winPre = Config.winPre;
    m_winPost = Config.winPost;
    m_alphaNormParam = Config.AlphaNormParam;

    m_isMedianPositive = Config.isMedianPositive;

    filtSrc = new double[ m_length ];
    filtDst = new double[ m_length ];

	
    //Low Pass Smoothing Filter Config
    m_FilterConfigParams.ord = Config.LPOrd;
    m_FilterConfigParams.ACoeffs = Config.LPACoeffs;
    m_FilterConfigParams.BCoeffs = Config.LPBCoeffs;
	
    m_FiltFilt = new FiltFilt( m_FilterConfigParams );
	
    //add delta threshold
    m_Delta = Config.Delta;
}

void DFProcess::deInitialise()
{
    delete [] filtSrc;

    delete [] filtDst;

    delete [] m_filtScratchIn;

    delete [] m_filtScratchOut;

    delete m_FiltFilt;
}

void DFProcess::process(double *src, double* dst)
{
    if (m_length == 0) return;

    removeDCNormalize( src, filtSrc );

    m_FiltFilt->process( filtSrc, filtDst, m_length );

    medianFilter( filtDst, dst );
}


void DFProcess::medianFilter(double *src, double *dst)
{
    int i,k,j,l;
    int index = 0;

    double val = 0;

    double* y = new double[ m_winPost + m_winPre + 1];
    memset( y, 0, sizeof( double ) * ( m_winPost + m_winPre + 1) );

    double* scratch = new double[ m_length ];

    for( i = 0; i < m_winPre; i++)
    {
        if (index >= m_length) break;

	k = i + m_winPost + 1;

	for( j = 0; j < k; j++)
	{
	    y[ j ] = src[ j ];
	}
	scratch[ index ] = MathUtilities::median( y, k );
	index++;
    }

    for(  i = 0; i + m_winPost + m_winPre < m_length; i ++)
    {
        if (index >= m_length) break;

			 
	l = 0;
	for(  j  = i; j < ( i + m_winPost + m_winPre + 1); j++)
	{
	    y[ l ] = src[ j ];
	    l++;
	}

	scratch[ index++ ] = MathUtilities::median( y, (m_winPost + m_winPre + 1 ));
    }

    for( i = std::max( m_length - m_winPost, 1); i < m_length; i++)
    {
        if (index >= m_length) break;

	k = std::max( i - m_winPre, 1);

	l = 0;
	for( j = k; j < m_length; j++)
	{
	    y[ l ] = src[ j ];

	    l++;
	}
		
	scratch[ index++ ] = MathUtilities::median( y, l); 
    }


    for( i = 0; i < m_length; i++ )
    {
	//add a delta threshold used as an offset when computing the smoothed detection function
	//(helps to discard noise when detecting peaks)	
	val = src[ i ] - scratch[ i ] - m_Delta;
		
	if( m_isMedianPositive )
	{
	    if( val > 0 )
	    {
		dst[ i ]  = val;
	    }
	    else
	    {
		dst[ i ]  = 0;
	    }
	}
	else
	{
	    dst[ i ]  = val;
	}
    }
	
    delete [] y;
    delete [] scratch;
}


void DFProcess::removeDCNormalize( double *src, double*dst )
{
    double DFmax = 0;
    double DFMin = 0;
    double DFAlphaNorm = 0;

    MathUtilities::getFrameMinMax( src, m_length, &DFMin, &DFmax );

    MathUtilities::getAlphaNorm( src, m_length, m_alphaNormParam, &DFAlphaNorm );

    for( unsigned int i = 0; i< m_length; i++)
    {
	dst[ i ] = ( src[ i ] - DFMin ) / DFAlphaNorm; 
    }
}