Title page for ETD etd-03082009-174318


Document Type Master's Dissertation
Author Van Zyl, Jan Louis
Email joesopa@gmail.com
URN etd-03082009-174318
Document Title Objective determination of vowel intelligibility of a cochlear implant model
Degree Master of Engineering
Department Electrical, Electronic and Computer Engineering
Supervisor
Advisor Name Title
Prof J J Hanekom Committee Chair
Keywords
  • objective speech intelligibility model
  • cochlear implant
  • speech intelligibility
  • acoustic model
  • acoustic analysis
  • confusion matrix
  • objective speech perception model
Date 2009-04-23
Availability unrestricted
Abstract
The goal of this study was to investigate the methodology in designing a vowel intelligibility model that can objectively predict the outcome of a vowel confusion test performed with normal hearing individuals listening to a cochlear implant acoustic model. The model attempts to mimic vowel perception of a cochlear implantee mathematically. The output of the model is the calculated probability of correct identification of vowel tokens and the probability of specific vowel confusions in a subjective vowel confusion test. In such a manner, the model can be used to aid cochlear implant research by complementing subjective listening tests. The model may also be used to test hypotheses concerning the use and relationship of acoustic cues in vowel identification.

The objective vowel intelligibility model consists of two parts: the speech processing component (used to extract the acoustic cues which allow vowels to be identified) and the decision component (simulation of the decision making that takes place in the brain). Acoustic cues were extracted from the vowel sounds and used to calculate probabilities of identifying or confusing specific vowels. The confusion matrices produces by the objective vowel perception model were compared with results from subjective tests performed with normal hearing listeners listening to an acoustic cochlear implant model. The most frequent confusions could be predicted using the first two formant frequencies and the vowel duration as acoustic cues. The model could predict the deterioration of vowel recognition when noise was added to the speech being evaluated. The model provided a first approximation of vowel intelligibility and requires further4 development to completely predict speech perception of cochlear implantees.

University of Pretoria 2008

Please cite as follows:

Van Zyl, J 2008, Objective determination of vowel intelligibility of a Cochlear implant model, MEng dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-03082009-174318/ >

C187/gm

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