次へ: Experiments
上へ: Multipitch Detection Algorithm
戻る: Detection of the number
Detection of s and Spectral Envelopes
図:
An example of the overfitted model of harmonic structure
where corresponds to of the true
[keepaspectratio=true,width=.95]/lab/common/publications/kameoka/Fig/2003ICA04overfit.eps

In the previous process, the ML procedure allows to aqcuire local
optimal solutions of without distinction of the true s, harmonics or subharmonics.
Therefore, the true s must somehow be discovered by replacing
each by each to their multiples.
Consider now that is fixed and a degree of freedom is given to every and consequently
allows to extract the spectral envelope, i.e., the relative amplitudes of
the partials.
If the ML estimate of after the previous peocess corresponds to
subharmonics, the ML model must overfit the given spectrum. For example, if
is of true , the model should form a harmonic
structure whose odd ordered harmonics are extremly small in comparison
with even ordered ones (Fig 3).
From this point of
view, the problem of obtaining the true s and the spectral envelope can
also be handled with the information criterion. The process shown below is done with
all remaining harmonicGMMs after the previous process.
 Replace the representative means to
where is an integer number whose initial value is 1. The number
of Gaussians limited below the Nyquist logfrequency is denoted as
.
 Estimate the ML model parameters by EM algorithm. Here we only
update and should be updated to
 Calculate AIC with equation (10). The number of free parameters here
is . If the AIC increases, the process should be
interrupted and the
is considered as
the detected , and if not, add to and return to step1.
図:
Detected contour of a single speaker
図:
Reference contour corresponding to figure 3

表 1:
Results for a single speaker

Accuracy(%) 
Speech file 
Cepstrum 
Proposed 
`myisda01' 
88.2 
98.0 
`myisda02' 
88.4 
99.0 
`myisda03' 
84.8 
98.1 
`myisda04' 
85.1 
92.4 
`myisda05' 
76.8 
93.7 
`fymsda01' 
86.3 
98.5 
`fymsda02' 
87.1 
97.5 
`fymsda03' 
83.3 
95.8 
`fymsda04' 
86.7 
96.8 
`fymsda05' 
85.2 
96.0 
次へ: Experiments
上へ: Multipitch Detection Algorithm
戻る: Detection of the number
平成16年3月25日