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diff --git a/src/loris/ReassignedSpectrum.h b/src/loris/ReassignedSpectrum.h new file mode 100644 index 0000000..cd8ae69 --- /dev/null +++ b/src/loris/ReassignedSpectrum.h @@ -0,0 +1,229 @@ +#ifndef INCLUDE_REASSIGNEDSPECTRUM_H +#define INCLUDE_REASSIGNEDSPECTRUM_H +/* + * 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 + * + * + * ReassignedSpectrum.h + * + * Definition of class Loris::ReassignedSpectrum. + * + * Kelly Fitz, 7 Dec 1999 + * loris@cerlsoundgroup.org + * + * http://www.cerlsoundgroup.org/Loris/ + * + */ + +#include "FourierTransform.h" +#include <vector> + +// begin namespace +namespace Loris { + +// --------------------------------------------------------------------------- +// class ReassignedSpectrum +// +//! Computes a reassigned short-time Fourier spectrum using the transform +//! method of Auger and Flandrin. +// +class ReassignedSpectrum +{ +// -- public interface -- +public: + //! An unsigned integral type large enough + //! to represent the length of any transform. + typedef FourierTransform::size_type size_type; + +// --- lifecycle --- + + //! Construct a new instance using the specified short-time window. + //! Transform lengths are the smallest power of two greater than twice the + //! window length. + ReassignedSpectrum( const std::vector< double > & window ); + + //! Construct a new instance using the specified short-time window and + //! its time derivative. + //! Transform lengths are the smallest power of two greater than twice the + //! window length. + ReassignedSpectrum( const std::vector< double > & window, + const std::vector< double > & windowDerivative ); + + // compiler-generated copy, assign, and destroy are sufficient + +// --- operations --- + + //! Compute the reassigned Fourier transform of the samples on the half open + //! range [sampsBegin, sampsEnd), aligning sampCenter with the center of + //! the analysis window. + //! + //! \param sampsBegin pointer representing the beginning of + //! the (half-open) range of samples to transform + //! \param sampCenter the sample in the range that is to be + //! aligned with the center of the analysis window + //! \param sampsEnd pointer representing the end of + //! the (half-open) range of samples to transform + //! + //! \pre sampsBegin must not be past sampCenter + //! \pre sampsEnd must be past sampCenter + //! \post the transform buffers store the reassigned + //! short-time transform data for the specified + //! samples + void transform( const double * sampsBegin, const double * pos, const double * sampsEnd ); + +// --- inquiry --- + + //! Return the length of the Fourier transforms. + size_type size( void ) const; + + //! Return read access to the short-time window samples. + //! (Peers may need to know about the analysis window + //! or about the scale factors in introduces.) + const std::vector< double > & window( void ) const; + + +// --- reassigned transform access --- + + //! Compute and return the convergence indicator, computed from the + //! mixed partial derivative of spectral phase, optionally used in + //! BW enhanced analysis as a convergence indicator. The convergence + //! value is on the range [0,1], 0 for a sinusoid, and 1 for an impulse. + //! + //! \param idx the frequency sample at which to evaluate the + //! transform + double convergence( long idx ) const; + + //! Return the reassigned frequency in fractional frequency + //! samples computed at the specified transform index. + //! + //! \param idx the frequency sample at which to evaluate the + //! transform + double reassignedFrequency( long idx ) const; + + //! Return the spectrum magnitude (absolute) + //! computed at the specified transform index. + //! + //! \param idx the frequency sample at which to evaluate the + //! transform + double reassignedMagnitude( long idx ) const; + + //! Return the phase in radians computed at the specified transform index. + //! The reassigned phase is shifted to account for the time + //! correction according to the corrected frequency. + //! + //! + //! \param idx the frequency sample at which to evaluate the + //! transform + double reassignedPhase( long idx ) const; + + //! Return the reassigned time in fractional samples + //! computed at the specified transform index. + //! + //! \param idx the frequency sample at which to evaluate the + //! transform + double reassignedTime( long idx ) const; + +// --- reassignment operations --- + + //! Compute the frequency correction at the specified frequency sample + //! using the method of Auger and Flandrin to evaluate the partial + //! derivative of spectrum phase w.r.t. time. + //! + //! Correction is computed in fractional frequency samples, because + //! that's the kind of frequency domain ramp we used on our window. + //! sample is the frequency sample index, the nominal component + //! frequency in samples. + double frequencyCorrection( long sample ) const; + + //! Compute the time correction at the specified frequency sample + //! using the method of Auger and Flandrin to evaluate the partial + //! derivative of spectrum phase w.r.t. frequency. + //! + //! Correction is computed in fractional samples, because + //! that's the kind of ramp we used on our window. + double timeCorrection( long sample ) const; + +// --- legacy support --- + + // These members are deprecated, and included only + // to support old code. New code should use the + // corresponding documented members. + // All of these members are deprecated. + + double reassignedPhase( long idx, double, double ) const + { return reassignedPhase( idx ); } + double reassignedMagnitude( double, long intBinNumber ) const + { return reassignedMagnitude( intBinNumber ); } + + // subscript operator + // The signature has changed, can no longer return a reference, + // but since the reference returned was const, this version should + // keep most old code working, if not all. + std::complex< double > operator[]( unsigned long idx ) const; + +private: + +// -- window building helpers -- + + // Build a pair of complex-valued windows, one having the frequency-ramp + // (time-derivative) window in the real part and the time-ramp window in the + // imagnary part, and the other having the unmodified window in the real part + // and, if computing mixed deriviatives, the time-ramp time-derivative window + // in the imaginary part. + // + // Input is the unmodified window function. + void buildReassignmentWindows( const std::vector< double > & window ); + + // Build a pair of complex-valued windows, one having the frequency-ramp + // (time-derivative) window in the real part and the time-ramp window in the + // imagnary part, and the other having the unmodified window in the real part + // and, if computing mixed deriviatives, the time-ramp time-derivative window + // in the imaginary part. + // + // Input is the unmodified window function and its time derivative, so the + // DFT kludge is unnecessary. + void buildReassignmentWindows( const std::vector< double > & window, + const std::vector< double > & windowDerivative ); + +// -- instance variables -- + + //! the FourierTransform for computing magnitude and phase + FourierTransform mMagnitudeTransform; + + //! the FourierTransform for computing time and frequency corrections + FourierTransform mCorrectionTransform; + + //! the original short-time analysis window samples + std::vector< double > mWindow; // W(n) + + //! the complex window used to compute the + //! magnitude/phase transform + std::vector< std::complex< double > > mCplxWin_W_Wtd; // real W(n), imag nW'(n) + + //! the complex window used to compute the + //! time/frequency correction transform + std::vector< std::complex< double > > mCplxWin_Wd_Wt; // real W'(n), imag nW(n) + +}; // end of class ReassignedSpectrum + +} // end of namespace Loris + +#endif /* ndef INCLUDE_REASSIGNEDSPECTRUM_H */ |