To the casual observer, transient stress results in a variety of physiological changes that can be seen in
the face. Although the conditions can be seen visibly, the conditions affect the emissivity and
absorption properties of the skin, which imaging spectrometers, commonly referred to as Hyperspectral
(HS) cameras, can quantify at every image pixel. The study reported on in this paper, using
Hyperspectral cameras, provides a basis for continued study of HS imaging to eventually quantify
biometric stress. This study was limited to the visible to near infrared (VNIR) spectral range. Signal
processing tools and algorithms have been developed and are described for using HS face data from
human subjects. The subjects were placed in psychologically stressful situations and the camera data
were analyzed to detect stress through changes in dermal reflectance and emissivity. Results indicate
that hyperspectral imaging may potentially serve as a non-invasive tool to measure changes in skin
emissivity indicative of a stressful incident. Particular narrow spectral bands in the near-infrared
region of the electromagnetic spectrum seem especially important. Further studies need to be
performed to determine the optimal spectral bands and to generalize the conclusions. The enormous
information available in hyperspectral imaging needs further analysis and more spectral regions need
to be exploited. Non-invasive stress detection is a prominent area of research with countless
applications for both military and commercial use including border patrol, stand-off interrogation,
access control, surveillance, and non-invasive and un-attended patient monitoring.
Obscurants containing glycols and glycerin, which are widely used in the entertainment industry to produce theatrical effects, are now being used in more concentrated forms in antitheft and riot control. While there have been several studies demonstrating that theatrical fogs are innocuous for humans, the toxicity of the denser fogs has not been examined. In this paper we review the results of previous safety studies of theatrical fog, summarize the effect of increasing concentrations of these obscurants on visibility, and then report on the physiological and biochemical impact of higher concentrations of these obscurants for several hours in rats. Our results suggest that even prolonged exposure to highly obscurant levels of propylene glycol / glycerin fog produces only minimal physiological aftereffects.
Blunt impact munitions are often used by civilian law enforcement and in military operations on urban terrain (MOUT) missions to dissuade individuals and groups from approaching valued assets. The use of blunt munitions (rubber-ball or sponge) is predicated on their effectiveness as aversive stimuli; the effectiveness is weighed against the risk of serious injury or death. However, little empirical evidence supports effectiveness. Here, we use a paintball gaming context to study the effects of blunt impact on performance and approach behaviors. Volunteers individually traversed a course in which targets offer the opportunity to gain for accuracy. While completing the targeting task, subjects were bombarded with paintballs, which progressively became more numerous and the impact more intense as the subjects neared goal locations. Initial data suggest that over 30 blunt impacts by paintballs delivered at 280 ft/sec over 30 to 100 ft are insufficient to overcome intrinsic and extrinsic approach motivations or impair targeting or advance performance in an overwhelming majority of subjects. Our apparent ceiling effect was surprising. A sub-comparison of the few subjects who stopped the game before the end with those who did not suggests that personality factors influence the effectiveness of blunt impact as a deterrent. While paintballs differ from traditional blunt impact munitions on a number of physical characteristics, impact that was sufficient to repeatedly bruise volunteers was not an effective deterrent.