/Users/richardeakin/projects/libsms/trunk/src/cepstrum.c File Reference

routines for different Fast Fourier Transform Algorithms More...

#include "sms.h"
#include <gsl/gsl_matrix.h>
#include <gsl/gsl_linalg.h>
#include <gsl/gsl_blas.h>

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Defines
#define	COEF   ( 8 * powf(PI, 2))
#define	CHOLESKY   1
Functions
void	FreeDCepstrum (CepstrumMatrices *m)
void	AllocateDCepstrum (int nPoints, int nCoeff, CepstrumMatrices *m)
void	sms_dCepstrum (int sizeCepstrum, sfloat *pCepstrum, int sizeFreq, sfloat *pFreq, sfloat *pMag, sfloat fLambda, int iMaxFreq)
	Discrete Cepstrum Transform.
void	sms_dCepstrumEnvelope (int sizeCepstrum, sfloat *pCepstrum, int sizeEnv, sfloat *pEnv)
	Spectrum Envelope from Cepstrum.
void	sms_spectralEnvelope (SMS_Data *pSmsData, SMS_SEnvParams *pSpecEnvParams)
	main function for computing spectral envelope from sinusoidal peaks

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Detailed Description

routines for different Fast Fourier Transform Algorithms

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Define Documentation

#define CHOLESKY   1

#define COEF   ( 8 * powf(PI, 2))

Referenced by sms_dCepstrum().

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Function Documentation

void AllocateDCepstrum	(	int	nPoints,
		int	nCoeff,
		CepstrumMatrices *	m
	)

References FreeDCepstrum().

Referenced by sms_dCepstrum().

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void FreeDCepstrum

(

CepstrumMatrices *

m

)

Referenced by AllocateDCepstrum().

void sms_dCepstrum	(	int	sizeCepstrum,
		sfloat *	pCepstrum,
		int	sizeFreq,
		sfloat *	pFreq,
		sfloat *	pMag,
		sfloat	fLambda,
		int	iMaxFreq
	)

Discrete Cepstrum Transform.

method for computing cepstrum aenalysis from a discrete set of partial peaks (frequency and amplitude)

This implementation is owed to the help of Jordi Janer (thanks!) from the MTG, along with the following paper: "Regularization Techniques for Discrete Cepstrum Estimation" Olivier Cappe and Eric Moulines, IEEE Signal Processing Letters, Vol. 3 No.4, April 1996

Todo:

add anchor point add at frequency = 0 with the same magnitude as the first peak in pMag. This does not change the size of the cepstrum, only helps to smoothen it at the very beginning.

Parameters:

	sizeCepstrum	order+1 of the discrete cepstrum
	pCepstrum	pointer to output array of cepstrum coefficients
	sizeFreq	number of partials peaks (the size of pFreq should be the same as pMag
	pFreq	pointer to partial peak frequencies (hertz)
	pMag	pointer to partial peak magnitudes (linear)
	fLambda	regularization factor
	iMaxFreq	maximum frequency of cepstrum

References AllocateDCepstrum(), COEF, PI, PI_2, sfloat, and sms_sine().

Referenced by sms_spectralEnvelope().

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void sms_dCepstrumEnvelope	(	int	sizeCepstrum,
		sfloat *	pCepstrum,
		int	sizeEnv,
		sfloat *	pEnv
	)

Spectrum Envelope from Cepstrum.

from a set of cepstrum coefficients, compute the spectrum envelope

Parameters:

	sizeCepstrum	order + 1 of the cepstrum
	pCepstrum	pointer to array of cepstrum coefficients
	sizeEnv	size of spectrum envelope (max frequency in bins)

Todo:

does this have to be a pow2

Parameters:

pEnv

pointer to output spectrum envelope (real part only)

References EXP, sfloat, sms_error(), sms_fft(), and sms_power2().

Referenced by sms_spectralEnvelope().

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void sms_spectralEnvelope	(	SMS_Data *	pSmsData,
		SMS_SEnvParams *	pSpecEnvParams
	)

main function for computing spectral envelope from sinusoidal peaks

Magnitudes should already be in linear for this function. If pSmsData->iEnvelope == SMS_ENV_CEP, will return cepstrum coefficeints If pSmsData->iEnvelope == SMS_ENV_FBINS, will return linear magnitude spectrum

Parameters:

	pSmsData	pointer to SMS_Data structure with all the arrays necessary
	pSpecEnvParams	pointer to a structure of parameters for spectral enveloping

References SMS_SEnvParams::fLambda, SMS_SEnvParams::iAnchor, SMS_SEnvParams::iMaxFreq, SMS_SEnvParams::iOrder, SMS_SEnvParams::iType, SMS_SEnvParams::nCoeff, SMS_Data::nEnvCoeff, SMS_Data::nTracks, SMS_Data::pFSinAmp, SMS_Data::pFSinFreq, SMS_Data::pSpecEnv, sfloat, sms_dCepstrum(), sms_dCepstrumEnvelope(), SMS_ENV_FBINS, and sms_error().

Referenced by sms_analyze().

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