|
CMU |
Dragon |
IBM |
Front-end |
39 features (MFCC, energy)
|
36 features (MFCC, energy)
PLP
LDA + normalization
|
- |
Segmentation |
Cross-entropy measure
GMM classification
|
CI phone recognition
Kullback-Leibler distance
|
GMMs + BIC
|
Acoustic Model |
Tied states
MLLR adaptation
|
Baum-Welch adaptation
Word-end in clustering
Speaker normalization
|
Only F0 and F1
Focus-specific adaptn.
DT clustering
OFS transforms
MLLR adaptation
|
Language Model |
CU-CMU SLM toolkit
64K words
1st pass - trigrams
Rescoring - 4-grams
|
57K vocabulary
Interpolated trigrams
Adapted remote corpora
|
64K lexicon
4-gram mixture LM
|
Decoder |
N-best lists
Rescoring with 4-grams
|
Multipass wordgraph
MLLR + Xword trigram
|
- |
Performance |
18.5% WER |
26.9% WER |
17.7% WER |