2018-02-152018-02-15December 22015-12December 2http://hdl.handle.net/10657/2114In this thesis, I describe a novel method to conduct stress studies via the combination of a physiological and an observational information channel. The method enables the quantification of aroused emotional states and their disambiguation into positive or negative instances. The physiological channel targets sympathetic responses and is materialized as a perspiratory signal extracted from thermal imagery of the perinasal area. The observational channel is materialized via decoding of facial expressions. Decoding is usually performed in the visible spectrum, however I have developed an algorithm to carry this out using thermal imagery instead. Thus, thermal imaging is used for both physiological and observational analysis. The potential of this dual-unobtrusive methodology was demonstrated with two stress studies. The first study was about surgeons' interaction with laparoscopic training boxes --- representative of the dexterous genre. The second study was about operator overloading where the participants played a car driving game while being interrupted by phone calls and text messages.application/pdfengThe author of this work is the copyright owner. UH Libraries and the Texas Digital Library have their permission to store and provide access to this work. Further transmission, reproduction, or presentation of this work is prohibited except with permission of the author(s).Stress modelFacial expressionsEmotionsHuman behavior2018-02-15Thesisborn digital