Abstract
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This paper deals with speech signal as significant indicator of psychological stress when the speaker is involved in a stressful activity. The investigation of speaker¡¯s stress is based on specific changes in short-time spectrum of vowel phonemes. For each selected signal segment, the spectrum is computed by means of two different methods: Fourier transformation and chirp transformation. Comparative results between both spectra serve for speaker¡¯s stress detection. In case of speech under stress, the obtained spectra differ towards the higher frequencies due to enhanced pitch modulation observed in the envelope of the chirp spectrum. For use in our experiments, a new database of speech under stress consisting of data collected during oral examinations at our university was created.
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