Voice stress extraction
Grażyna Demenko · 2008
results in a slow, low-pitched speech with little high-frequency energy.Furthermore, the fact that these physiological effects are rather universal means that there are common tendencies concerning the acoustic determinants of basic emotions.Apart from these individual differences, some studies show an increase in intensity and fundamental frequency, a stronger concentration of energy above 500 Hz and an increase in speech rate ([7], [11]).A number of studies have considered analysis of speech under both simulated and actual stress condition, though the interpretation of speech characteristics is not unambiguous.The research frequently reports on conflicting results, due to differences in experimental design, categorization of actual or simulated stress, and/or interpretation of results.The studies using actors and simulated stress or emotions have the advantage of a controlled environment.The major disadvantage is, however, an artificial experimental design which can result in producing highly exaggerated misrepresentations of emotions in speech.Another group focuses on the analysis of authentic recordings coming from actual situations.There is usually no doubt as to the presence of stress in these recordings, however there is a problem of categorization of the homogeneous classes of stress.This study focuses therefore on the analysis of stress produced in response to the occurrences in the people's surroundings, perceived by them as unusual, anomalous and impossible to be controlled.The research aims at a preliminary extraction of acoustic features which are produced as a result of a relatively homogenous group of stressors. Acoustic determinants of stressSpeech Data Out of 20 000 recordings selected from the database, the recordings of a few hundred of different speakers were chosen for analysis.It was assumed that a particular situation which makes a person call 977 determines more or less notably the way he/she speaks.The following situational contexts were taken into account: A. Relatively unequivocal contexts 1. Direct life hazard -extreme stress (ES).A situation in which the person calling or his/her friends/relatives, etc. are in a direct threat of losing their life produces extreme stress, which can be easily perceived.2. Indirect life/heath hazard, a threat of losing property -limited stress (S).A situation in which the person calling or his/her friends/relatives, etc. are in an indirect threat of losing their life, health or property produces stress whose intensity depends on the individual characteristics of a person. Tragedies of life -depression (D).A situation in which the person calling or his/her friends/relatives, etc. are potentially threatened by losing their life/health as a result of a terminal illness (or planned suicide), etc. also other misfortunes in life