Gaze direction and head rotation are powerful cues that inform humans about another person's attention, intentions and even emotion. Previous research has focused on understanding how people make judgements about individual faces in direct view. However in everyday life, people are often presented with groups of faces and need to judge where the attention of that group is directed, such as in group conversations or when giving presentations. This thesis presents research whose aim is to better understand how gaze direction and head rotation are perceived in the visual periphery and in groups. First, observers' perception of gaze deviation in the visual periphery was tested, using psychophysical methods and modelling. The results showed that observers' ability to judge gaze perception is severely limited, and that observers' judgements are severely biased by head rotation in the visual periphery. Second, observers' ability to perceive the average gaze or head direction of a group of spatially distributed faces was investigated. This was done using equivalent noise analysis, a technique which gives estimates for observers' internal noise (how certain they are in their judgements of any individual face) and their effective sample size (how many faces they are able to combine into their average). The findings revealed that head rotation was averaged with less uncertainty and greater effective sample size than gaze deviation, suggesting that observers can more precisely and efficiently pool information about head rotation than gaze. Finally, averaging of heads and gaze stimuli presented in temporal sequences was analysed using the same equivalent noise technique and compared to spatial averaging. In sequences, the differences in processing between head and gaze direction disappear, suggesting that poor peripheral perception of gaze is the limit on our averaging of gaze cues.

The present study used eye-tracking to investigate whether a model’s gaze direction influences the way observers look at the entire body of the model and how this interacts with the observer and the model’s gender. Participants viewed individual male and female computer agents during both a free-viewing task and a rating task to evaluate the attractiveness of each character. The results indicated that both male and female participants primarily gazed at the models’ faces. Participants also spent more time scanning the face when rating the attractiveness of each model. Observers tended to scan faces with a direct gaze longer than faces with an averted gaze for both the free-viewing and attractiveness rating tasks. Lastly, participants evaluated models with a direct gaze as more attractive than models with an averted gaze. As these results occurred for pictures of computer agents, and not actual people, this suggests that direct gaze, and faces in general, are powerful for engaging attention. In summary, both task requirements and gaze direction modified face viewing preference.

The present study used eye-tracking to investigate whether a model’s gaze direction influences the way observers look at the entire body of the model and how this interacts with the observer and the model’s gender. Participants viewed individual male and female computer agents during both a free-viewing task and a rating task to evaluate the attractiveness of each character. The results indicated that both male and female participants primarily gazed at the models’ faces. Participants also spent more time scanning the face when rating the attractiveness of each model. Observers tended to scan faces with a direct gaze longer than faces with an averted gaze for both the free-viewing and attractiveness rating tasks. Lastly, participants evaluated models with a direct gaze as more attractive than models with an averted gaze. As these results occurred for pictures of computer agents, and not actual people, this suggests that direct gaze, and faces in general, are powerful for engaging attention. In summary, both task requirements and gaze direction modified face viewing preference.

Different studies have shown that faces seen with a direct gaze (creating eye contact) are more likely to be recognized than faces seen with a laterally deviated gaze. The present work was aimed at determining underlying processes of this gaze direction effect. More precisely, whether this effect was due to a more elaborated encoding of faces with direct gaze because of the social importance of the eye contact was tested. Results obtained showed that the gaze direction effect is a highly sensitive effect which influence on memory for faces is probably more incidental than previously hypothesized./ Différentes études ont montré que les visages vus avec un regard direct (créant un contact visuel) ont plus de chance dêtre reconnus que les visages vus avec un regard dévié latéralement. Ce travail avait pour but de déterminer la nature des processus sous-jacents à cet effet de la direction du regard. Plus précisément, nous avons testé lhypothèse dun encodage plus élaboré des visages avec un regard direct dû à la signification sociale du contact visuel. Les résultats obtenus ont montré que leffet de la direction du regard est un effet très sensible dont linfluence sur la mémoire pourrait être plus incidente que ce qui avait été proposé dans la littérature.

Companies have long been interested in gauging the customer’s level of interest in their advertisements. By analyzing the gaze direction of individuals viewing a public advertisement, we can infer their level of engagement. Head pose detection allows us to deduce pertinent information about gaze direction. Using video sensors, machine learning methods, and image processing techniques, information pertaining to the head pose of people viewing advertisements can be automatically collected and mined. We propose a method for the coarse classification of head pose from low-resolution images in crowded scenes captured through a single camera and under different lighting conditions. Our method improves on the technique described in [1]; we introduce several modifications to the latter scheme to improve classification accuracy. First, we devise a mechanism that uses a cascade of three binary Support Vector Machines (SVM) classifiers instead of a single multi-class classifier. Second, we employ a bigger dataset for training by combining eight publicly available databases. Third, we use two sets of appearance features, Similarity Distance Map (SDM) and Gabor Wavelet (GW), to train the SVM classifiers. The scheme is tested with cross validation using the dataset and on videos we collected in a lab experiment. We found a significant improvement in the results achieved by the proposed method over existing schemes, especially for video pose classification. The results show that the proposed method is more robust under varying light conditions and facial expressions and in the presences of facial accessories compared to [1].

Smarta och hjälpsamma teknologier kommer ut varje år och blir snabbt en del avvår vardag. Teknologierna blir mer och mer medvetna om när och var vi behöverdem och stödjer oss i att nå personliga mål såsom att ta cykeln istället för bilen tilljobbet. Dock har dessa teknologier begränsad funktionalitet när vi inte interagerarmed dem, vilket resulterar i att vi behöver interagera med dem och förlorar fokusfrån andra uppgifter.Vi tror att det ett decennium fram kommer att finnas enkla applikationsgränssnitti glasögon med förstärkt verklighet (AR-glasögon). Förstärkt verklighet kan vara ettkraftfullt verktyg för att skapa ett skikt över den riktiga världen så önskar vi ocksåatt gränssnitten inte stör upplevelsen av den riktiga världen.I denna studie har vi undersökt vilka möjligheter det finns i att skicka visuellastimuli till en användare på ett subtilt eller subliminalt sätt. Slutsatsen är att detinte uppenbarligen går att säga att det visuella stimuli i systemet somimplementerades i denna studie var subliminalt. Dock så kunde vi dra slutsatsenatt tiden det tar att upptäcka ett visuellt stimuli som gradvis ökar med tiden skiljersig mellan användare och att användare är mer benägna att fokusera på objekt somär placerade i ögonhöjd, vilket bör beaktas när man ska bestämma vart visuellastimuli ska placeras. / Smart and helpful technologies are released every year and are quick to become partof our everyday lives. Technologies are becoming more aware of when and where weneed them and help us to achieve personal goals, such as taking the bike instead ofthe car to work. Still, many of these smart technologies have only limitedfunctionality without us interacting with them, resulting in us having to interactwith them and losing focus on other tasks.We believe that a decade from now, some future application interfaces will reside inaugmented reality smart glasses. While augmented reality can be a powerful toolwhen overlaying the real world, we also wish that the augmented reality interfacesdo not break the immersion of everyday life.In this study, we have explored the possibilities of sending visual cues to a user in asubtle or even a subliminal way in an augmented reality setting. In conclusion, thereis no obvious answer to whether a cue in the system that was implemented in thisstudy was subliminal. However, we found that the time it took to perceive a cue thatgradually intensifies with time differed between people and that people are moreinclined to focus on objects placed at an eye-level height which should be taken inconsideration when deciding on where to place visual cues.

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La quantité d’informations à laquelle nous sommes chaque jour confrontésconditionne notre survie à la capacité de détecter rapidement ce qui est le pluspertinent dans notre environnement. Nos cerveaux ont ainsi évolué afin dedéclencher, en réponse aux stimuli pertinents, des changements d’état affectif quinous informent alors de l’existence et de la nature de ces stimuli. Or, tandis que lesétats émotionnels, induits par des états corporels, impactent notre perception desstimuli émotionnels, l’influence de ces états corporels sur l’évaluation de lapertinence de stimuli externes est méconnue. Nous avons ici examiné le rôle queces états du corps, transitoires et socialement signifiants, jouent dans l'évaluation dela pertinence des expressions faciales de menace. Lors de nos testscomportementaux, où variaient le degré de pertinence des stimuli et le focusattentionnel, nous avons modulé l'état corporel des participants à l’aide de posturesdominantes ou non dominantes réalisées avant les tâches. Nous avons alorsdémontré que ces postures influencent l'évaluation de la pertinence des expressionsde menace, en accord avec le statut social qu’elles incarnent. De plus, ceci n’a étérévélé que lorsque le traitement de ces stimuli était implicite, soulignant alors lasaillance de ces derniers. Ainsi, nos résultats démontrent que les états corporelsinfluencent non seulement l'évaluation de la pertinence, mais la déterminent, car desstimuli par ailleurs pertinents ne sont plus évalués comme tels selon la postureadoptée. Ces résultats suggèrent que l’état du corps interagit avec nos états affectifspour signaler à l’observateur quels indices sociaux sont pertinents. / Given the quantity of information with which we are constantly confronted, our survival depends on the ability to rapidly detect and attend to what is most relevant. To this end, our brains have evolved to trigger changes in our affective state in response to relevant objects and events, which inform us of their existence and of their nature. While body-induced affective states impact the perception of congruent emotional stimuli, it is still unknown whether body-induced affective states influence the manner in which the relevance of external stimuli is determined and therefore perceived. Here, we examined the role that socially meaningful transient body states play in the evaluation of relevance of facial displays of threat. In a series of behavioral experiments, we modulated participants’ body state, instructing them to hold dominant or non-dominant postures prior to behavioral tests, in which we varied the degree of relevance of the stimuli and the focus of attention. We first demonstrated that these body postures, in accordance with the social status they embody, influenced the evaluation of the relevance of threatening facial displays. Moreover, this impact occurred where facial displays were processed implicitly, highlighting the saliency of these social cues. Overall, our studies demonstrate, that body states, not only influence the evaluation of relevance, but determine it, as otherwise relevant social cues, were no longer evaluated as such. These findings suggest that body states interact with affective states to signal which social cues are relevant to the observer.

The introduction of input devices with natural user interfaces in gaming hardware has changed the way we interact with games. Hardware with motion-sensing and gesture recognizing capabilities remove the constraint of interacting with games through typical traditional devices like mouse-keyboard and gamepads. This changes the way we approach games and how the game communicates back to us as the player opening new levels of interactivity. This thesis covers how eye tracker technology can be used to affect rendering effects in games.

Made available in DSpace on 2015-03-03T15:07:32Z (GMT). No. of bitstreams: 1 HeltonMP_DISSERT.pdf: 2119610 bytes, checksum: c84371c4f412913aaf46e9775fe03da1 (MD5) Previous issue date: 2010-11-26 / The fundamental senses of the human body are: vision, hearing, touch, taste and smell. These senses are the functions that provide our relationship with the environment. The vision serves as a sensory receptor responsible for obtaining information from the outside world that will be sent to the brain. The gaze reflects its attention, intention and interest. Therefore, the estimation of gaze direction, using computer tools, provides a promising alternative to improve the capacity of human-computer interaction, mainly with respect to those people who suffer from motor deficiencies. Thus, the objective of this work is to present a non-intrusive system that basically uses a personal computer and a low cost webcam, combined with the use of digital image processing techniques, Wavelets transforms and pattern recognition, such as artificial neural network models, resulting in a complete system that performs since the image acquisition (including face detection and eye tracking) to the estimation of gaze direction. The obtained results show the feasibility of the proposed system, as well as several feature advantages. / Os sentidos fundamentais do corpo humano s?o: vis?o, audi??o, tato, gusta??o(ou paladar) e olfato. Estes constituem as fun??es que propiciam o nosso relacionamento com o ambiente. A vis?o funciona como um receptor sensorial respons?vel pela capta??o de informa??es do mundo exterior que ser?o enviadas ao c?rebro. O olhar reflete a sua aten??o, inten??o e interesse. Sendo assim, a estima??o da dire??o do olhar, a partir de modelos computacionais, possibilita uma alternativa promissora para melhorar a capacidade de intera??o homem-m?quina, inclusive dos portadores de defici?ncias motoras. O objetivo deste trabalho consiste em apresentar um sistema n?o-intrusivo que utiliza basicamente um computador pessoal e uma webcam de baixo custo que, quando aliados ao uso das t?cnicas de processamento digital de imagens, transformadas Wavelets e reconhecimento de padr?es, com as redes neurais artificiais, resultam em um sistema completo que realiza desde a aquisi??o de imagens (passando pela detec??o da face e rastreamento dos olhos) ate a estima??o da dire??o do olhar. Os resultados apresentados mostram a viabilidade do sistema proposto assim como diversas vantagens em seu uso