Context-Dependent HMM set

Set of HMM states with the same base phone and state location. More...

Data Structures
struct	CD_State_Set
	Context-dependent state set, equivalent to HTK_HMM_State, part of pseudo phone. More...
struct	CD_State_Set
	Context-dependent state set, equivalent to HTK_HMM_State, part of pseudo phone. More...
struct	_cd_set
	Context-dependent HMM set (called "pseudo") for a logical context. More...
struct	HMM_CDSET_INFO
	Top structure to hold all the HMM sets. More...
struct	_HMM_logical
	Logical HMM to map logical names to physical/pseudo HMM. More...
Defines
#define	CD_STATE_SET_STEP   10
	CD_State_Set memory allocation step.
Typedefs
typedef _cd_set	CD_Set
	Context-dependent HMM set (called "pseudo") for a logical context.
typedef _HMM_logical	HMM_Logical
	Logical HMM to map logical names to physical/pseudo HMM.

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Detailed Description

Set of HMM states with the same base phone and state location.

This structure will be used to handle cross-word triphone on the 1st pass. At a triphone HMM at the edge of a word in the tree lexicon, the state nodes should have a set of HMM states with the same base phone of all triphones at the same location instead of a single state information. This context-dependent HMM set for cross-word triphone is also called as "pseudo" phone in Julius.

When computing the 1st pass, the maximum (or average or N-best average) value from the likelihoods of state set will be taken as the output probability of the states instead of the actual cross-word triphone.

This approximated value will be fixed by re-computation on the 2nd pass.

See also:

htk_hmm.h

libsent/src/hmminfo/cdhmm.c

libsent/src/hmminfo/cdset.c

libsent/src/hmminfo/guess_cdHMM.c

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Typedef Documentation

typedef struct _cd_set CD_Set

Context-dependent HMM set (called "pseudo") for a logical context. Context-dependent HMM set for a logical context (e.g. "a-k", "e+b", "e", each corresponds to triphone list of "a-k+*", "*-e+b", "*-e+*").

typedef struct _HMM_logical HMM_Logical

Logical HMM to map logical names to physical/pseudo HMM. This data maps logical HMM name to physical (defined) HMM or pseudo HMM. The logical HMM names are basically loaded from HMMList mapping file. Biphone/monophone HMM names, not listed in the HMMList file, are mapped to pseudo phones, which represents the context-dependent HMM set. For example, if logical biphone HMM name "e-k" is defined in HMM definition file or its mapping is specified in the HMMList file, the Logical HMM name "e-k" will be mapped to the corresponding defined HMM. If "e-k" does not exist in both HMM definition file and HMMList file, triphones whose name matches "e-k+*" will be gathered to phone context-dependent HMM set "e-k", and the logical HMM name "e-k" will be mapped to this HMM set. The context-dependent HMM is also called a "pseudo" phone in Julius.

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