next up previous contents
Next: Examining Transitions Up: Examining Phonetic Information Transmission Previous: Experimental Setup

A Few Observations

Figure 5.2 shows all features transmitted as a percentage of the maximum. We observe the following:

1.
Multi-band feature transmission is always as good as or better than the comparable full-band system, except for frontness. On average, 60.94% of the features are transmitted for the multi-band system compared to 59.06% for the full-band system for 54000 acoustic frames.

2.
Low and sometimes mid frequency bands (often band 1 and sometimes band 2) transmit most of the feature information alone.

3.
There is much redundancy in phonetic information content in the sub-bands, as the sum of information transmission over all bands far exceeds 100%. Lippmann [7] has highlighted this redundancy as a source of human robustness to speech degradations.


  
Figure 5.2: Phonetic features transmitted as a percentage of maximum possible, as measured by mutual information. b1 thru b4 stand for band1 thru band4, mb stands for multi-band, and fb for full-band analysis.
\begin{figure}
\epsfxsize=2in
\centerline{\epsffile{bar_FeatTransm_all_new.eps}}
\end{figure}



Christophe Ris
1998-11-10