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

Detection of a given harmonic. More...

#include "sms.h"

Include dependency graph for harmDetection.c:

Defines
#define	N_FUND_HARM   6
#define	N_HARM_PEAKS   4
#define	FREQ_DEV_THRES   .07
#define	MAG_PERC_THRES   .6
#define	HARM_RATIO_THRES   .8
Functions
static int	GetClosestPeak (int iPeakCandidate, int nHarm, SMS_Peak *pSpectralPeaks, int *pICurrentPeak, int iRefHarmonic)
	get closest peak to a given harmonic of the possible fundamental
static int	ComparePeak (sfloat fRefHarmMag, SMS_Peak *pSpectralPeaks, int nCand, sfloat fRefHarmMagDiffFromMax)
	checks if peak is substantial
int	CheckIfHarmonic (sfloat fFundFreq, SMS_HarmCandidate *pCHarmonic, int nCand)
	check if the current peak is a harmonic of one of the candidates
static int	GoodCandidate (int iPeak, SMS_Peak *pSpectralPeaks, SMS_HarmCandidate *pCHarmonic, int nCand, SMS_PeakParams *pPeakParams, sfloat fRefFundamental)
	consider a peak as a possible candidate and give it a weight value,
static int	GetBestCandidate (SMS_HarmCandidate *pCHarmonic, int iRefHarmonic, int nGoodPeaks, sfloat fPrevFund)
	choose the best fundamental out of all the candidates
void	sms_harmDetection (SMS_AnalFrame *pFrame, sfloat fRefFundamental, SMS_PeakParams *pPeakParams)
	main harmonic detection function

---

Detailed Description

Detection of a given harmonic.

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Define Documentation

#define FREQ_DEV_THRES   .07

threshold for deviation from perfect harmonics

Referenced by GoodCandidate().

#define HARM_RATIO_THRES   .8

threshold for percentage of harmonics found

Referenced by GoodCandidate().

#define MAG_PERC_THRES   .6

threshold for magnitude of harmonics with respect to the total magnitude

Referenced by GoodCandidate().

#define N_FUND_HARM   6

number of harmonics to use for fundamental detection

Referenced by ComparePeak(), and GoodCandidate().

#define N_HARM_PEAKS   4

number of peaks to check as possible ref harmonics

Referenced by sms_harmDetection().

---

Function Documentation

int CheckIfHarmonic	(	sfloat	fFundFreq,
		SMS_HarmCandidate *	pCHarmonic,
		int	nCand
	)

check if the current peak is a harmonic of one of the candidates

Parameters:

	fFundFreq	frequency of peak to be tested
	pCHarmonic	all candidates accepted
	nCand	location of las candidate

Returns:

1 if it is a harmonic, 0 if it is not

Referenced by GoodCandidate().

static int ComparePeak	(	sfloat	fRefHarmMag,
		SMS_Peak *	pSpectralPeaks,
		int	nCand,
		sfloat	fRefHarmMagDiffFromMax
	)			[static]

checks if peak is substantial

check if peak is larger enough to be considered a fundamental without any further testing or too small to be considered

Parameters:

	fRefHarmMag	magnitude of possible fundamental
	pSpectralPeaks	all the peaks
	nCand	number of existing candidates
	fRefHarmMagDiffFromMax	value to judge the peak based on the difference of its magnitude compared to the reference

Returns:

1 if big peak, -1 if too small , otherwise return 0

References SMS_Peak::fMag, N_FUND_HARM, and sfloat.

Referenced by GoodCandidate().

static int GetBestCandidate	(	SMS_HarmCandidate *	pCHarmonic,
		int	iRefHarmonic,
		int	nGoodPeaks,
		sfloat	fPrevFund
	)			[static]

choose the best fundamental out of all the candidates

Parameters:

	pCHarmonic	array of candidates
	iRefHarmonic	reference harmonic number
	nGoodPeaks	number of candiates
	fPrevFund	reference fundamental

Returns:

the integer number of the best candidate

References SMS_HarmCandidate::fFreq, and sfloat.

Referenced by sms_harmDetection().

static int GetClosestPeak	(	int	iPeakCandidate,
		int	nHarm,
		SMS_Peak *	pSpectralPeaks,
		int *	pICurrentPeak,
		int	iRefHarmonic
	)			[static]

get closest peak to a given harmonic of the possible fundamental

Parameters:

	iPeakCandidate	peak number of possible fundamental
	nHarm	number of harmonic
	pSpectralPeaks	pointer to all the peaks
	pICurrentPeak	pointer to the last peak taken
	iRefHarmonic	reference harmonic number

Returns:

the number of the closest peak or -1 if not found

References sfloat.

Referenced by GoodCandidate().

static int GoodCandidate	(	int	iPeak,
		SMS_Peak *	pSpectralPeaks,
		SMS_HarmCandidate *	pCHarmonic,
		int	nCand,
		SMS_PeakParams *	pPeakParams,
		sfloat	fRefFundamental
	)			[static]

consider a peak as a possible candidate and give it a weight value,

Parameters:

	iPeak	iPeak number to be considered
	pSpectralPeaks	all the peaks
	pCHarmonic	all the candidates
	nCand	candidate number that is to be filled
	pPeakParams	analysis parameters
	fRefFundamental	previous fundamental

Returns:

-1 if not good enough for a candidate, return 0 if reached the top frequency boundary, return -2 if stop checking because it found a really good one, return 1 if the peak is a good candidate

Bug:

sfloat comparison to 0

References CheckIfHarmonic(), ComparePeak(), SMS_HarmCandidate::fFreq, SMS_Peak::fFreq, SMS_HarmCandidate::fFreqDev, SMS_HarmCandidate::fHarmRatio, SMS_HarmCandidate::fMag, SMS_Peak::fMag, SMS_HarmCandidate::fMagPerc, SMS_PeakParams::fRefHarmMagDiffFromMax, FREQ_DEV_THRES, GetClosestPeak(), HARM_RATIO_THRES, SMS_PeakParams::iRefHarmonic, SMS_PeakParams::iSoundType, MAG_PERC_THRES, N_FUND_HARM, sfloat, and SMS_SOUND_TYPE_NOTE.

Referenced by sms_harmDetection().

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void sms_harmDetection	(	SMS_AnalFrame *	pFrame,
		sfloat	fRefFundamental,
		SMS_PeakParams *	pPeakParams
	)

main harmonic detection function

find a given harmonic peak from a set of spectral peaks, put the frequency of the fundamental in the current frame

Parameters:

	pFrame	pointer to current frame
	fRefFundamental	frequency of previous frame
	pPeakParams	pointer to analysis parameters

Todo:

is it possible to use pSpectralPeaks instead of SMS_AnalFrame?

move pCHarmonic array to SMS_AnalFrame structure

• this will allow for analysis of effectiveness from outside this file This really should only be for sms_analyzeFrame

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Bug:

sfloat comparison to zero

References SMS_HarmCandidate::fFreq, SMS_Peak::fFreq, SMS_AnalFrame::fFundamental, SMS_PeakParams::fHighestFundamental, SMS_PeakParams::fLowestFreq, SMS_Peak::fMag, GetBestCandidate(), GoodCandidate(), SMS_PeakParams::iRefHarmonic, N_HARM_PEAKS, SMS_AnalFrame::pSpectralPeaks, and sfloat.

Referenced by sms_analyzeFrame().

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