segDecoder.c File Reference

Generic Viterbi-type decorder for segmental HMMs. More...

#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include <string.h>
#include "segCommon.h"
#include "segStdLib.h"
#include "segDecoder.h"

Data Structures
struct	node
	Node probability buffer storing SNPs and an ENP. More...
struct	StartNodeParameter
	Parameters realising rolling-SNP-array mechanism. More...
Defines
#define	ALLOC_ERR   -2
	Function return value when memory allocation failed.
#define	ERROR   -1
	Function return value when an error occurred.
#define	NO_ERROR   0
	Function return value when the function was executed successfully.
#define	PERMIT_BOTH   0x03
	Status for nodes that can be both start and end nodes (assigned by pre-cost partition).
#define	PERMIT_START   0x02
	Status for nodes that can be only a start node (assigned by pre-cost partition).
#define	PERMIT_END   0x01
	Status for nodes that can be only an end node (assigned by pre-cost partition).
#define	NO_PERMIT   0x00
	Status for nodes that can be neither start nor end node (assigned by pre-cost partition).
Typedefs
typedef node	NODE
	Node probability buffer storing SNPs and an ENP.
typedef StartNodeParameter	SNP_PARAM
	Parameters realising rolling-SNP-array mechanism.
Functions
double	segViterbiDecoder (SEG_DP_ITEM ***dpHist, SEG_SYNTAX *synt, double **spData, int *breakPt, int sT, int eT, int maxDur, SEG_DEC_PARAM *decParam)
	Generic Viterbi-type decorder for segmental HMMs.
int	segFreeDecoder (SEG_DP_ITEM **dpHist, int numStates)
	Free memory space storing all the paths in the trellis.

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Detailed Description

Generic Viterbi-type decorder for segmental HMMs.

Date:

09.06.2006, 21.06.2007 (revised)

Author:

Yoshinori Shiga @ CVSSP, University of Surrey

Note:

Introducing a concept of start and end node to M Russell & P Jackson's SEGVit ver.3 has achieved computationally- efficient decoding with effective pruning for segmental HMMs. This makes it possible to perform embedded recognition using context-sensitive (triphone) models, within a resonable time. A token-passing-style algorithm has been applied to reduce memory used.

Abbrev - SN: start node, EN: end node, SNP: start-node probability, ENP: end-node probability

Revision

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Function Documentation

int segFreeDecoder	(	SEG_DP_ITEM **	dpHist,
		int	numStates
	)

Free memory space storing all the paths in the trellis.

Parameters:

[in]	dpHist	Paths in the trellis for back-tracing
[in]	numStates	Number of states

Return values:

NO_ERROR

Successful execution

Author:

Yoshinori Shiga @ CVSSP, University of Surrey

double segViterbiDecoder	(	SEG_DP_ITEM ***	dpHist,
		SEG_SYNTAX *	synt,
		double **	spData,
		int *	breakPt,
		int	sT,
		int	eT,
		int	maxDur,
		SEG_DEC_PARAM *	decParam
	)

Generic Viterbi-type decorder for segmental HMMs.

Parameters:

[out]	dpHist	Paths in the trellis for back-tracing
[in]	synt	Syntax
[in]	spData	Acoustic feature vectors
[in]	breakPt	Break point attributes
[in]	sT	Utterance start time (frame #)
[in]	eT	Utterance end time (frame #)
[in]	maxDur	Maximal segment-duration (Dmax)
[in]	decParam	Decoder parameters

Return values:

	RTN_ERROR	Memory allocation error
	Otherwise	The best cost (minProb) computed

Author:

Yoshinori Shiga @ CVSSP, University of Surrey

Note:

The following functions are called internally: allocDpHistory(), initDecoder(), preCostPartition(), firstPropagator(), selector(), incSnpIdx(), propagator(), prunStartNode(), prunEndNode(), lastPropagator(), lastSelector(), and freeAllNode().

See also:

allocDpHistory(), initDecoder(), preCostPartition(), firstPropagator(), selector(), incSnpIdx(), propagator(), prunStartNode(), prunEndNode(), lastPropagator(), lastSelector() and freeAllNode().

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