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More info on Feature Parameters
User: kmaclean
Date: 9/23/2008 7:32 pm
Views: 3737
Rating: 10

The Julius 3.2 book  section 7. Feature parameter files (-input mfcfile) says:

Feature Parameter Types
It is necessary that the feature parameter format matches the original HMM training data feature format. However if all the necessary parameters for the HMM are held within the given feature parameter file,Julius will then automatically extract the appropriate parameters for recognition.

For example
If the parameter format below is used for training
      MFCC_E_D_N_Z = MFCC(12)+ ?MFCC(12)+ ?Pow(1) (CMN)                   25-dimension
Then for recognition you can also use feature parameter files other then MFCC_E_D_N_Z, such as
      MFCC_E_D_Z        = MFCC(12)+Pow(1)+?MFCC(12)+ ?Pow(1)
                                                           (CMN) 26-dimension
                                                                                                        or
     MFCC_E_D_A_Z = MFCC(12)+Pow(1)+ ?MFCC(12)+ ?Pow(1)
                     + ??MFCC(12) + ??Pow(1) (CMN)             39-dimension
The parameter file needs to contain all of the parameters used for the original training of the HMM model,
extra data contained with in the file will not be used.

where (from the HTK book):

_E has energy

_N absolute energy suppressed

_D has delta coe?cients

_A has acceleration coe?cients

_C is compressed

_Z has zero mean static coef.

_K has CRC checksum

_O has 0’th cepstral coef

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