The results showed that the perception of the intensity and directionality of the smell can be modulated through the virtual visual representation of the smell. The gas sensor output values obtained for a sequence of administration of 15 odorants are represented in Figure 10.This last condition will constitute most of the situations to which participants will be exposed within the virtual environment. At the perceptual level, cross-contamination results in the perception of a mixed smell, while different odorants are released at different times. In fact, the vast majority of those who reported noticing the stimulus identified it correctly, suggesting that this perception was real and was within conscious awareness.
IVR technologies provide virtual environments that mimic the complexity of the real world and, at the same time, give scientists many control and monitoring capabilities. OD control can be performed manually using simple software or computer-controlled using a custom software toolkit (Geneva Virtual Reality Elements, GeVre). Other authors have already highlighted how useful the inclusion of smell in an immersive virtual environment could be for virtual therapy in post-traumatic stress disorder resulting from a military attack or combat (Pair et al. Between the diffusers there was a fan that distributed the smell in the direction of the users so that the olfactory stimulus could be perceived as the users moved around the room.
For example, increasing the concentration of odors and the number of olfactory sources in the virtual environment will increase the likelihood of cross-contamination. This may influence the speed at which participants report detecting the scent; however, it is unlikely to have influenced the relationships between odor detection and other variables (for example, recently, immersive virtual reality (IVR) environments have become promising methods for immersing people in a near-real environment involving more senses. This DO can emit 3 different odors with different intensities depending on a virtual “smell field”, but the variation in the intensity of the odorant is mainly controlled by an increase in air flow. This platform allows researchers to benefit from the latest in virtual reality to create and use immersive scenarios.
The following sections present the results of different tests carried out in the OD to demonstrate their effectiveness in reliably emitting odors in the BBL-IS. This psychophysical experiment shows that, under normal conditions of use (ISI airflow similar to the flow of smelling air), participants should only detect changes in the nose due to odorants.