From d6073e01c933c77f1e2bc3c3fe1126d617003549 Mon Sep 17 00:00:00 2001
From: John Glover <glover.john@gmail.com>
Date: Fri, 8 Jul 2011 18:06:21 +0100
Subject: Start adding Loris files
---
src/loris/SpectralPeakSelector.C | 248 +++++++++++++++++++++++++++++++++++++++
1 file changed, 248 insertions(+)
create mode 100644 src/loris/SpectralPeakSelector.C
(limited to 'src/loris/SpectralPeakSelector.C')
diff --git a/src/loris/SpectralPeakSelector.C b/src/loris/SpectralPeakSelector.C
new file mode 100644
index 0000000..a6cbc15
--- /dev/null
+++ b/src/loris/SpectralPeakSelector.C
@@ -0,0 +1,248 @@
+/*
+ * This is the Loris C++ Class Library, implementing analysis,
+ * manipulation, and synthesis of digitized sounds using the Reassigned
+ * Bandwidth-Enhanced Additive Sound Model.
+ *
+ * Loris is Copyright (c) 1999-2010 by Kelly Fitz and Lippold Haken
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY, without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ *
+ * SpectralPeakSelector.C
+ *
+ * Implementation of a class representing a policy for selecting energy
+ * peaks in a reassigned spectrum to be used in Partial formation.
+ *
+ * Kelly Fitz, 28 May 2003
+ * loris@cerlsoundgroup.org
+ *
+ * http://www.cerlsoundgroup.org/Loris/
+ *
+ */
+
+#if HAVE_CONFIG_H
+ #include "config.h"
+#endif
+
+#include "SpectralPeakSelector.h"
+
+
+#include "Breakpoint.h"
+#include "Notifier.h"
+#include "ReassignedSpectrum.h"
+
+
+#include <cmath> // for abs and fabs
+
+
+// define this to use local minima in frequency
+// reassignment to detect "peaks", otherwise
+// magnitude peaks are used.
+#define USE_REASSIGNMENT_MINS 1
+//#undef USE_REASSIGNMENT_MINS
+
+
+// begin namespace
+namespace Loris {
+
+// ---------------------------------------------------------------------------
+// construction - constant resolution
+// ---------------------------------------------------------------------------
+SpectralPeakSelector::SpectralPeakSelector( double srate, double maxTimeCorrection ) :
+ mSampleRate( srate ),
+ mMaxTimeOffset( maxTimeCorrection )
+{
+}
+
+// ---------------------------------------------------------------------------
+// selectPeaks
+// ---------------------------------------------------------------------------
+// Collect and return magnitude peaks in the lower half of the spectrum,
+// ignoring those having frequencies below the specified minimum, and
+// those having large time corrections.
+//
+// If the minimumFrequency is unspecified, 0 Hz is used.
+//
+// There are two strategies for doing. Probably each one should be a
+// separate class, but for now, they are just separate functions.
+
+Peaks
+SpectralPeakSelector::selectPeaks( ReassignedSpectrum & spectrum,
+ double minFrequency )
+{
+#if defined(USE_REASSIGNMENT_MINS) && USE_REASSIGNMENT_MINS
+
+ return selectReassignmentMinima( spectrum, minFrequency );
+
+#else
+
+ return selectMagnitudePeaks( spectrum, minFrequency );
+
+#endif
+}
+
+// ---------------------------------------------------------------------------
+// selectReassignmentMinima (private)
+// ---------------------------------------------------------------------------
+Peaks
+SpectralPeakSelector::selectReassignmentMinima( ReassignedSpectrum & spectrum,
+ double minFrequency )
+{
+ using namespace std; // for abs and fabs
+
+ const double sampsToHz = mSampleRate / spectrum.size();
+ const double oneOverSR = 1. / mSampleRate;
+ const double minFreqSample = minFrequency / sampsToHz;
+ const double maxCorrectionSamples = mMaxTimeOffset * mSampleRate;
+
+ Peaks peaks;
+
+ int start_j = 1, end_j = (spectrum.size() / 2) - 2;
+
+ double fsample = start_j;
+ do
+ {
+ fsample = spectrum.reassignedFrequency( start_j++ );
+ } while( fsample < minFreqSample );
+
+ for ( int j = start_j; j < end_j; ++j )
+ {
+
+ // look for changes in the frequency reassignment,
+ // from positive to negative correction, indicating
+ // a concentration of energy in the spectrum:
+ double next_fsample = spectrum.reassignedFrequency( j+1 );
+ if ( fsample > j && next_fsample < j + 1 )
+ {
+ // choose the smaller correction of fsample or next_fsample:
+ // (could also choose the larger magnitude?)
+ double freq;
+ int peakidx;
+ if ( (fsample-j) < (j+1-next_fsample) )
+ {
+ freq = fsample * sampsToHz;
+ peakidx = j;
+ }
+ else
+ {
+ freq = next_fsample * sampsToHz;
+ peakidx = j+1;
+ }
+
+ // still possible that the frequency winds up being
+ // below the specified minimum
+ if ( freq >= minFrequency )
+ {
+ // keep only peaks with small time corrections:
+ double timeCorrectionSamps = spectrum.reassignedTime( peakidx );
+ if ( fabs(timeCorrectionSamps) < maxCorrectionSamples )
+ {
+ double mag = spectrum.reassignedMagnitude( peakidx );
+ double phase = spectrum.reassignedPhase( peakidx );
+
+ // this will be overwritten later in analysis,
+ // might be ignored altogether, only used if the
+ // mixed derivative convergence indicator is stored
+ // as bandwidth in Analyzer:
+ double bw = spectrum.convergence( j );
+
+
+ // also store the corrected peak time in seconds, won't
+ // be able to compute it later:
+ double time = timeCorrectionSamps * oneOverSR;
+ Breakpoint bp( freq, mag, bw, phase );
+ peaks.push_back( SpectralPeak( time, bp ) );
+ }
+ }
+
+ }
+ fsample = next_fsample;
+ }
+
+ /*
+ debugger << "SpectralPeakSelector::selectReassignmentMinima: found "
+ << peaks.size() << " peaks" << endl;
+ */
+
+ return peaks;
+
+}
+
+// ---------------------------------------------------------------------------
+// selectMagnitudePeaks (private)
+// ---------------------------------------------------------------------------
+Peaks
+SpectralPeakSelector::selectMagnitudePeaks( ReassignedSpectrum & spectrum,
+ double minFrequency )
+{
+ using namespace std; // for abs and fabs
+
+ const double sampsToHz = mSampleRate / spectrum.size();
+ const double oneOverSR = 1. / mSampleRate;
+ const double minFreqSample = minFrequency / sampsToHz;
+ const double maxCorrectionSamples = mMaxTimeOffset * mSampleRate;
+
+ Peaks peaks;
+
+ int start_j = 1, end_j = (spectrum.size() / 2) - 2;
+
+ double fsample = start_j;
+ do
+ {
+ fsample = spectrum.reassignedFrequency( start_j++ );
+ } while( fsample < minFreqSample );
+
+ for ( int j = start_j; j < end_j; ++j )
+ {
+ if ( spectrum.reassignedMagnitude(j) > spectrum.reassignedMagnitude(j-1) &&
+ spectrum.reassignedMagnitude(j) > spectrum.reassignedMagnitude(j+1) )
+ {
+ // skip low-frequency peaks:
+ double fsample = spectrum.reassignedFrequency( j );
+ if ( fsample < minFreqSample )
+ continue;
+
+ // skip peaks with large time corrections:
+ double timeCorrectionSamps = spectrum.reassignedTime( j );
+ if ( fabs(timeCorrectionSamps) > maxCorrectionSamples )
+ continue;
+
+ double mag = spectrum.reassignedMagnitude( j );
+ double phase = spectrum.reassignedPhase( j );
+
+ // this will be overwritten later in analysis,
+ // might be ignored altogether, only used if the
+ // mixed derivative convergence indicator is stored
+ // as bandwidth in Analyzer:
+ double bw = spectrum.convergence( j );
+
+ // also store the corrected peak time in seconds, won't
+ // be able to compute it later:
+ double time = timeCorrectionSamps * oneOverSR;
+ Breakpoint bp ( fsample * sampsToHz, mag, bw, phase );
+ peaks.push_back( SpectralPeak( time, bp ) );
+
+ } // end if itsa peak
+ }
+
+ /*
+ debugger << "SpectralPeakSelector::selectMagnitudePeaks: found "
+ << peaks.size() << " peaks" << endl;
+ */
+ return peaks;
+}
+
+
+} // end of namespace Loris
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