Title: Detection
Of Vowels From A Recorded Phrase Based On Positive And Negative Portions
Of Oscillogram With Suitable Rectification Level.
Abstract: Our prime
concern is with the recognition of vowels in sounds produced by the human
vocal organs, and more specifically, the sounds, which are used in human
speech. In this paper we tried to analyze and trace vowels in different phrases
of the speech. An algorithm was previously designed which would automatically
spot the vowels in the recorded phrase by using rectifier cutoff line and
latter on reverse and forward tracking modules were introduced. This approach
can further be improved if we could introduce rectification line for both
positive and negative phase of the oscillogram (waveform). It has been observed
by analyzing different oscillograms, that the stable portion of the vowels
crosses the rectification level fixed at 50% of the maximum value (3FFFh
for positive and C000h for negative portion) in 16-bit sample wave file.
By the introduction of rectification level both in negative and positive
portion of waveform about 80% of the vowel body can be identified. The algorithm
of reverse and forward tracking based on turning points can identify the
rest 20% portion. Thus by having information of start and end addresses of
vowels, their formants can be determined with available software like praat.
Vowels can be distinguished by the frequency values of the two or three formants,
which are called F1, F2 and F3.
Authors: H. M. Chohan,
J. S. Mirza