Thesis - Instituto de Telecomunicações

46 CHAPTER 3. INFORMATION SOURCESmaxSCmax20tttTime0 max halfFigure 3.6: Measures extracted from a SCR event.In the psychological context, related to emotion/affect detection, the EDA signal hasbeen recurringly used, revealing relevant information. The EDA signal is largely knownto be used for lie detection as one of the signals of the polygraph system. Figure 3.7,depicts the first polygraph system that introduced a psychogalvanometer to measure theelectrodermal activity. This system was created by Leonardo Keeler in 1931 [166]. In [99]the detection of stress in a driving scenario uses a setup gathering ECG, video image andEDA signals; the receptivity of a talk in a conference was measured by an EDA glove thatevery conference participant in the audience was wearing [188]; a wearable computer wasdeveloped that was capable of monitoring EDA signals [187, 189]; when interacting with acomputer application that provoked a stress state, the EDA signal was the base monitoredsignal for the detection of user frustration [63]; after the characterization of stimulus thatprovoked high and low emotional valences, a classification system used EDA to separate thetwo states [98]; an anxiety state was evaluated using the EDA signal in [168]; the sensitivityof EDA to different types of odor was studied in [14] and [162]; the response to fear wasrecently addressed based on the analysis of the EDA response [176].