Speech Coding Strategies: Past, Present and Future Stuart Rosen University College London
Introduction and basic concepts
PPT Slide
What are the essential purposes of a speech processor?
What other functions can and might be implemented in a speech processor?
Common elements in speech processing
But speech processing schemes vary significantly in other ways
Also
Multi-channel systems
What is a filter bank?
The filter bank analogy
The (not very distant) past
A multi-channel ‘whole-speech’ ‘wavey’ simultaneous cochlear implant
Simulations can give us some idea of what an implant user might experience
But ...caveat perceptor!
Noise-excited Vocoding
Separate channels in a 6-channel simulation
... and when summed together.
Never mind the quality... feel the intelligibility.
Effects of channel number
More effects of channel number
The role of frequency selectivity for perceiving speech in noise
Run an experiment
Issues to consider
A feature extraction approach to multi-channel stimulation
Which features to extract? … speech processing ... (ordinary Australian speech)
Fundamental frequency (F0) alone ... went up the hill ...
Connected Discourse Tracking shows that an unintelligible auditory signal can nevertheless significantly improve lipreading ability.
Second formant (F2) + F0 ... the mouse ran ...
First formant (F1) + F2 +F0 ...all the King’s ...
Summary of a feature extraction strategy
The present
Continuous Interleaved Sampling (CIS)
Continuous Interleaved Sampling
CIS in detail
CIS stimulation pattern
Necessity is the mother of invention
Spectral Peak Strategy - SPEAK
SPEAK stimulation pattern
SPEAK in quiet
Advantages of peak-picking in noise
Electrodograms show advantages of peak-picking in pink noise (The clown had a funny face.)
Advanced Combination Encoders - ACE
Stimulation Pattern - ACE
ACE stimulation pattern
The future of speech processing?
Improved processing in noise: A general convergence of approaches with acoustic hearing aids?
References
Obrigado!
Email: stuart@phon.ucl.ac.uk
Home Page: http://www.phon.ucl.ac.uk/home/stuart/home.htm
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