include/cmn.h File Reference

Apply Cepstral Mean Normalization (CMN) to the set of input mfc frames. More...

#include <sphinxbase_export.h>
#include <prim_type.h>
#include <fe.h>

Go to the source code of this file.

Data Structures
struct	cmn_t
	wrapper of operation of the cepstral mean normalization. More...
Defines
#define	CMN_WIN_HWM   800
#define	CMN_WIN   500
Typedefs
typedef enum cmn_type_e	cmn_type_t
	Types of cepstral mean normalization to apply to the features.
Enumerations
enum	cmn_type_e { CMN_NONE = 0, CMN_CURRENT, CMN_PRIOR }
	Types of cepstral mean normalization to apply to the features.
Functions
SPHINXBASE_EXPORT cmn_type_t	cmn_type_from_str (const char *str)
	Convert string representation (from command-line) to cmn_type_t.
SPHINXBASE_EXPORT cmn_t *	cmn_init (int32 veclen)
SPHINXBASE_EXPORT void	cmn (cmn_t *cmn, mfcc_t **mfc, int32 varnorm, int32 n_frame)
	CMN for the whole sentence.
SPHINXBASE_EXPORT void	cmn_prior (cmn_t *cmn, mfcc_t **incep, int32 varnorm, int32 nfr)
	CMN for one block of data, using prior mean.
SPHINXBASE_EXPORT void	cmn_prior_update (cmn_t *cmn)
	Update prior mean based on observed data.
SPHINXBASE_EXPORT void	cmn_prior_set (cmn_t *cmn, mfcc_t const *vec)
	Set the prior mean.
SPHINXBASE_EXPORT void	cmn_prior_get (cmn_t *cmn, mfcc_t *vec)
	Get the prior mean.
SPHINXBASE_EXPORT void	cmn_free (cmn_t *cmn)
Variables
SPHINXBASE_EXPORT const char *	cmn_type_str []
	String representations of cmn_type_t values.

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Detailed Description

Apply Cepstral Mean Normalization (CMN) to the set of input mfc frames.

By subtractingthe mean of the input from each frame. C0 is also included in this process. This function operates on an entire utterance at a time. Hence, the entire utterance must be available beforehand (batchmode).

Definition in file cmn.h.

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Function Documentation

SPHINXBASE_EXPORT void cmn	(	cmn_t *	cmn,
		mfcc_t **	mfc,
		int32	varnorm,
		int32	n_frame
	)

CMN for the whole sentence.

Parameters:

cmn	In/Out: cmn normalization, which contains the cmn_mean and cmn_var)
mfc	In/Out: mfc[f] = mfc vector in frame f
varnorm	In: if not FALSE, variance normalize the input vectors to have unit variance (along each dimension independently); Irrelevant if no cmn is performed
n_frame	In: Number of frames of mfc vectors

Definition at line 150 of file cmn.c.

References cmn(), cmn_t::cmn_mean, cmn_t::cmn_var, E_INFO, E_INFOCONT, NULL, and cmn_t::veclen.

Referenced by cmn(), and cmn_init().

SPHINXBASE_EXPORT void cmn_prior	(	cmn_t *	cmn,
		mfcc_t **	incep,
		int32	varnorm,
		int32	nfr
	)

CMN for one block of data, using prior mean.

Parameters:

cmn	In/Out: cmn normalization, which contains the cmn_mean and cmn_var)
incep	In/Out: mfc[f] = mfc vector in frame f
varnorm	This flag should always be 0 for live
nfr	Number of incoming frames

Definition at line 146 of file cmn_prior.c.

References cmn_t::cmn_mean, cmn_prior(), CMN_WIN_HWM, E_FATAL, cmn_t::nframe, cmn_t::sum, and cmn_t::veclen.

Referenced by cmn_prior().

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