Les études menées dans cette thèse portent sur le rôle de la couleur dans l'attention visuelle. Nous avons tenté de comprendre l'influence de l'information couleur dans les vidéos sur les mouvements oculaire, afin d'intégrer les attributs couleur dans un modèle de saillance visuelle. Pour cela, nous avons analysé différentes caractéristiques des mouvements oculaires d'observateurs regardant librement des vidéos en deux conditions: couleur et niveaux de gris. Nous avons également comparé les régions principales de regard sur des vidéos en couleur avec celles en niveaux de gris. Il est apparu que les informations de couleur modifient légèrement les caractéristiques de mouvement oculaire comme la position de l'œil et la durée des fixations. Cependant, nous avons constaté que la couleur augmente le nombre de régions de regard. De plus, cet influence de la couleur s'accroît au cours du temps. En nous appuyant sur ces résultats, nous avons proposé une méthode de calcul des cartes de saillance couleur. Nous avons intégré ces cartes dans un modèle de saillance existant. / The studies conducted in this thesis focus on the role of colour in visual attention. We tried to understand the influence of colour information on the eye movements while observing videos, to incorporate colour information into a model of visual saliency. For this, we analysed different characteristics of eye movements of observers while freely watching videos in two conditions: colour and grayscale videos. We also have compared the main regions of regard of colour videos with those of grayscale. We observed that colour information influences only moderately, the eye movement characteristics such as the position of gaze and duration of fixations. However, we found that colour increases the number of the regions of interest in video stimuli. Moreover, this varies across time. Based on these observations, we proposed a method to compute colour saliency maps for videos. We have incorporated colour saliency maps in an existing model of saliency.

Les jeux vidéo occupent une place importante dans notre société. Cependant, leur conception ne prend aujourd'hui que peu en compte les spécificités de l'interaction joueur-jeu vidéo, qui sont déterminantes pour une expérience de jeu optimale. L'objectif de cette thèse était de comprendre l'influence de différents choix de conception des interfaces visuelles des jeux vidéo sur la performance et le comportement du regard des joueurs. Ces interfaces, généralement dynamiques et complexes, sont composées de trois sources d'information : les objets avec lesquels le joueur interagit et l'arrière-plan, qui composent la scène d'action principale, ainsi que les informations contextuelles superposées à la scène principale. Sept expériences ont été réalisées pour comprendre le partage attentionnel entre ces sources dans le cadre d'une activité de jeu vidéo. Les caractéristiques de l'arrière-plan, des informations contextuelles et de la tâche ont été manipulées. La performance et les mouvements du regard des joueurs ont été enregistrés. Les résultats ont montré que le partage attentionnel entre deux sources d'information (e.g., scène d'action et informations contextuelles) est facilité lorsqu'elles ne se chevauchent pas. Lorsque qu'elles se chevauchent nécessairement (e.g., objets et arrière-plan), les caractéristiques de mouvement et de complexité de l'arrière-plan et la difficulté de la tâche modulent très largement la dégradation de la performance. Un modèle théorique de partage attentionnel entre deux sources visuelles d'information superposées est proposé. Des recommandations sont établies pour la conception des jeux vidéo, mais aussi des environnements virtuels en général. / Video games take an increasingly important place in our society. Nowadays, however, their design doesn't take enough into account the specificity of player-game interaction, which is essential for an optimal play experience. The thesis' goal was to understand the impact of different design choices for video games visual interfaces on players' performance and gaze behavior. These dynamic and complex interfaces include three information sources: the objects that the player interacts with and the background, which make up together the main action scene, and the contextual information superimposed on the main scene. Seven experiments were made to understand how attention is shared between these sources during video game activity. The characteristics of the background, of the contextual information and of the game task were manipulated. The performance was measured while participants' eye movements were recorded. The results showed that attention sharing between two sources (e.g., the action scene and contextual information) is optimal when the two sources do not overlap at all. When they necessarily overlap (e.g., objects superimposed on a background), the nature of background movement, the background visual complexity and the difficulty of the task can strongly modulate the performance decrease. A theoretical model of attention sharing between two superimposed sources of visual information is proposed. Practical recommendations are drawn up for video game design, but also for virtual environments design.

Dans la vie de tous les jours, lorsque nous regardons le monde qui nous entoure, nous bougeons constamment nos yeux. Notre regard se porte successivement sur différents endroits du champ visuel afin de capter l'information visuelle. Ainsi, nos yeux se stabilisent sur deux à trois régions différentes par seconde pendant des périodes appelées fixations. Entre deux fixations, nous réalisons des mouvements rapides des yeux pour déplacer notre regard vers une autre région ; on parle de saccades oculaires. Ces mouvements oculaires sont étroitement liés à l'attention. Quels sont les processus attentionnels mis en jeu lors de l'exploration de scènes ? Comment les facteurs liés à la scène ou à la consigne donnée pour l'exploration modifient-ils les paramètres des mouvements oculaires ? Comment ces modifications évoluent-elles au cours de l'exploration ? Dans cette thèse, nous proposons d'analyser conjointement les données oculométriques et électroencéphalographiques (EEG) pour mieux comprendre les processus attentionnels impliqués dans le traitement de l'information visuelle acquise pendant l'exploration de scènes. Nous étudions à la fois l'influence de facteurs de bas niveau, c'est-à-dire l'information visuelle contenue dans la scène et de haut niveau, c'est-à-dire la consigne donnée aux observateurs. Dans une première étude, nous avons considéré les facteurs de haut niveau à travers la modulation de la tâche à réaliser pour l'exploration des scènes. Nous avons choisi quatre tâches : l'exploration libre, la catégorisation, la recherche visuelle et l'organisation spatiale. Ces tâches ont été choisies car elles impliquent des traitements de l'information visuelle de nature différente et peuvent être classées en fonction de leur niveau de difficulté ou de demande attentionnelle. Dans une seconde étude, nous nous sommes focalisées plus particulièrement sur la recherche visuelle et l'influence de la contrainte temporelle. Enfin, dans une troisième étude, nous considérons les facteurs de bas niveau à travers l'influence d'un distracteur visuel perturbant l'exploration libre. Pour les deux premières études, nous avons enregistré conjointement les mouvements oculaires et les signaux EEG d'un grand nombre de sujets. L'analyse conjointe des signaux EEG et oculométriques permet de tirer profit des deux méthodes. L'oculométrie permet d'accéder aux mouvements oculaires et donc au déploiement de l'attention visuelle sur la scène. Elle permet de connaitre à quel moment et quels endroits de la scène sont regardés. L'EEG permet, avec une grande résolution temporelle, de mettre en avant des différences dans les processus attentionnels selon la condition expérimentale. Ainsi, nous avons montré des différences entre les tâches au niveau des potentiels évoqués par l'apparition de la scène et pour les fixations au cours de l'exploration. De plus, nous avons mis en évidence un lien fort entre le niveau global de l'activité EEG observée sur les régions frontales et les durées de fixation mais aussi des marqueurs de résolution de la tâche au niveau des potentiels évoqués liés à des fixations d'intérêt. L'analyse conjointe des données EEG et oculométriques permet donc de rendre compte des différences de traitement liées à différentes demandes attentionnelles. / In everyday life, when we explored the word, we moved continually our eyes. We focus your gaze successively on different location of the visual field, in order to get the visual information. In this way, our eyes became stable on two or three different regions per second, during period called fixation. Between two fixations, we make fast movements of the eyes to move our gaze to another position; it was called saccade. Eye movements are closely linked to attention. What are the attentional processes involved during scene exploration? How factors related to the scene or the task modify the parameters of eye movements? How these changes evolve during the exploration? In the thesis, we proposed to jointly analyze eye movements and electroencephalographic (EEG) data to better understand attentional processes involved during the processing of the visual information acquired during the exploration of scenes. We focused on low and high level factors. Low level factors corresponded to the visual information included in the scene and high level factors corresponded to the instruction give to observers. In a first study, we considered high level factors by manipulating the instructions for observers. We chose four tasks: free-exploration, categorization, visual search and spatial organization. These tasks were chosen because they involved different visual information processing and can be classified by level of difficulty or attentional demands. In a second study, we focused on the visual search task and on the influence of a time constraint. Finally, in a third study, we considered low level factors by analyzing the influence of a distractor disturbing the free-exploration of scenes. For the two first experiments, we jointly recorded eye movements and EEG signals of a large number of observers. The joint analysis of EEG and eye movement data takes advantage of the two methods. Eye tracking allowed to access to eye movements parameters and therefore to the visual attention deployment. It allowed knowing when and where the regions of the scene were gazed at. EEG allowed to access to differences on attentional processes depending on the experimental condition, with a high temporal resolution. We found differences between tasks for evoked potentials elicited by the scene onset and by fixations along the exploration. Furthermore, we demonstrated a strong link between the global EEG activity observed over frontal regions and fixation durations but also markers of the solving of the task on evoked potentials elicited by fixations of interest. Therefore, joint analysis of EEG and eye movement data allowed to report different processes related to attentional demanding.

Made available in DSpace on 2014-12-17T14:55:16Z (GMT). No. of bitstreams: 1 RafaelBG_TESE.pdf: 2529249 bytes, checksum: b16afb21de612f10dcfa5acb69028967 (MD5) Previous issue date: 2013-08-02 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Visual attention is a very important task in autonomous robotics, but, because of its complexity, the processing time required is significant. We propose an architecture for feature selection using foveated images that is guided by visual attention tasks and that reduces the processing time required to perform these tasks. Our system can be applied in bottom-up or top-down visual attention. The foveated model determines which scales are to be used on the feature extraction algorithm. The system is able to discard features that are not extremely necessary for the tasks, thus, reducing the processing time. If the fovea is correctly placed, then it is possible to reduce the processing time without compromising the quality of the tasks outputs. The distance of the fovea from the object is also analyzed. If the visual system loses the tracking in top-down attention, basic strategies of fovea placement can be applied. Experiments have shown that it is possible to reduce up to 60% the processing time with this approach. To validate the method, we tested it with the feature algorithm known as Speeded Up Robust Features (SURF), one of the most efficient approaches for feature extraction. With the proposed architecture, we can accomplish real time requirements of robotics vision, mainly to be applied in autonomous robotics / A aten??o visual ? uma importante tarefa em rob?tica aut?noma, mas devido ? sua complexidade, o tempo de processamento necess?rio ? significativo. Prop?e-se uma arquitetura para sele??o de features usando imagens foveadas que ? guiada por tarefas envolvendo aten??o visual e que reduz o tempo de processamento para realizar tais tarefas. O sistema proposto pode ser aplicado para aten??o bottom-up ou top-down. O modelo de foveamento determina quais escalas devem ser utilizadas no algoritmo de extra??o de features. O sistema ? capaz de descartar features que n?o s?o essenciais para a realiza??o da tarefa e, dessa forma, reduz o tempo de processamento. Se a f?vea ? corretamente posicionada, ent?o ? poss?vel reduzir o tempo de processamento sem comprometer o desempenho da tarefa. A dist?ncia da f?vea para o objeto tamb?m ? analisada. Caso o sistema visual perca o tracking na aten??o top-down, estrat?gias b?sicas de reposicionamento da f?vea podem ser aplicadas. Experimentos demonstram que ? poss?vel reduzir em at? 60% o tempo de processamento com essa abordagem. Para validar o m?todo proposto, s?o realizados testes com o algoritmo de extra??o de features SURF, um dos mais eficientes existentes. Com a arquitetura proposta para sele??o de features, ? poss?vel cumprir requisitos de um sistema de vis?o em tempo-real com poss?veis aplica??es na ?rea de rob?tica

Na tomada de decisão, o conteúdo afetivo dos possíveis resultados é determinante para escolha. Pessoas com diferentes tolerâncias a estes resultados têm distintas tolerâncias a risco. Decisões são moduladas minimizando-se resultados aversivos (emoção negativa e dor), e diferenças individuais relacionadas a aversão a risco poderiam ser preditoras de percepção de dor. Aqui, objetiva-se explorar se indivíduos com distintas aversões a risco financeiro teriam diferente percepção de dor física, social e imagética (contemplação de imagens de baixa valência/alto alerta). Em decisões financeiras, características pessoais de sensibilidade a preço ou produto seriam reveladas na maneira como o cenário de decisão é visualmente explorado. Outro objetivo é investigar como se dá a modulação da atenção visual em decisões financeiras de acordo com características individuais, manipulando-se diferentes formas de apresentação de preço. Espera-se colaborar para o entendimento dos processos de decisão em humanos, e contribuir para a construção de um modelo amplo de tomada de decisão. / The human behavior has its basis in dynamic coalitions of networks of brain areas underling emotion and cognition. It is believed that the decision is made through simulations of possible outcomes, and the affective content of these outcomes is crucial to the choice. Individuals experience different levels of tolerance to aversive results, these differences shape tolerance to risk, and it might also shape tolerance to pain. Therefore, pain perception could be an important component of decision-making. We explored the relationship between individual differences in pain perception (nociception, social exclusion and imagetic pain, the displeasure caused by low valence and high arousal images) and financial risk aversion. We also investigated how individual differences in economic decisions are reflected in visual attention, in different prices scenario. We hope to collaborate to a better understanding of the decision processes in humans, and to contribute to the conception of a more complete model of decision-making.

O processamento visual se dá por duas vias, Dorsal (localização/movimento) mobilizada por TRS (tempo de reação simples), e Ventral (forma/cor) mobilizada por TER (tempo de reação escolha). Apresentamos uma nova abordagem para se investigar a distribuição dos recursos atencionais. Os métodos psicofísicos vigentes amostram repetidas vezes poucos pontos. Optou-se por amostrar muitos pontos na tela do computador poucas vezes, obtendo-se amostragem de uma grande área. Obteve-se um mapa de detalhamento da distribuição atencional. Experimentos de atenção voluntária: I. Tarefa de TRS, mobilizando a via Dorsal. Na situação de atenção difusa. II. TRE, mobilizando a via Ventral. Os estímulos possíveis diferiam na cor e foram respondidos ao se pressionar um botão, atenção difusa. III. TRE, focando-se a atenção em duas molduras, caracterizando atenção dividida. Os resultados demonstraram um favorecimento do hemicampo inferior para a TRS e um favorecimento do hemicampo superior para TER. Apareceram dois focos na atenção dividida fortalecendo a hipótese da divisão atencional. / Visual processing has two pathways: Dorsal (localization/movement) mobilized for Simple Reaction Time tasks (SRT); Ventral (shape/color) mobilized for Choice Reaction Time tasks (CRT). We presented an approach to investigate visual attentional resources. Usual psychophysical methods sample many times few points. We opted to sample many points few times aiming to enlarge the sampled visual field. It was obtained major details of the attentional distribution. Voluntary attention task: I. SRT, for Dorsal pathway. Stimuli were different in color answered triggering a button, in a diffusion attention paradigm. II. CRT, for Ventral pathway. Stimuli were two different color answered by triggering a button for each color in a diffuse paradigm. III. CRT, experimental subject instructed to focus attention in two frames for a splitted attention paradigm. Results showed anisotropy in the diffuse attention distribution, favouring the lower hemifield for SRT and superior hemifield for CRT. The splitted attention paradigm evidenced the presence of two attentional focuses.

Devido ao alto número de propagandas que um consumidor é exposto em um único dia, torna-se fundamental que as empresas produzam anúncios que atinjam de forma efetiva seu público-alvo. Um anúncio precisa chamar a atenção de uma pessoa e, ainda, impactar em suas atitudes. Ressalta-se que fatores como gênero e nível de envolvimento do consumidor são variáveis que impactam na atenção dedicada a um anúncio e nas ações posteriores a este. Ainda, a forma como o anúncio é elaborado, ou seja, o tipo de anúncio, pode interferir nas reações dos consumidores. Este estudo teve por objetivo identificar como diferentes tipos de anúncio, sejam estes direcionados ao público masculino, feminino ou neutros impactam na atenção visual e nas atitudes em relação a estes anúncios e, também, como o gênero e o nível de envolvimento influenciam nessa relação. Através de um pré-teste, foram selecionadas seis imagens para compor o estudo. Através de um experimento, os participantes foram divididos em três grupos e submetidos a visualização de um dos tipos de anúncio escolhido. A coleta de dados foi dada por meio do eye-tracking e de questionários e os dados foram analisados por meio da análise fatorial, testes de hipótese e complementados com estatística descritiva. Foi identificado que o tipo de anúncio impacta na atenção visual e nas atitudes em relação ao anúncio. Em relação às variáveis moderadoras do estudo, foi visto que o gênero impacta apenas nas respostas dos anúncios considerados masculinos e que, de forma mais evidente, o nível de envolvimento impacta nas respostas dos anúncios, principalmente nas atitudes em relação ao anúncio / Due to the high number of advertisements that a consumer is exposed in a single day, it is critical that companies produce ads that effectively reach their target audience. An ad needs to catch a person\'s attention and still impact their attitudes. It should be noted that factors such as gender and level of consumer involvement are variables that impact on the attention devoted to an ad and on the actions subsequent to it. Yet, the way the ad is designed, that is, the type of ad, can interfere with consumer reactions. The purpose of this study was to identify how different types of advertisements, whether directed at the male, female or neutral public, impact on visual attention and attitudes towards these ads, and how gender and level of involvement influence this relationship. Through a pre-test, six images were selected to compose the study. Then, through an experiment, the participants were divided into three groups and submitted to the visualization of one of the chosen ad types. Data were collected through eye-tracking and questionnaires and the data were analyzed through factorial analysis, hypothesis tests and complemented with descriptive statistics. It has been identified that the type of ad impacts on visual attention and attitudes toward the ad. Regarding the moderating variables of the study, it was seen that the gender impacts only on the responses of the ads considered masculine and that, more clearly, the level of involvement impacts on the responses of the ads, mainly in the attitudes towards the advertisement

Recently cognitive principles have been discussed for Conceptual Modeling with the aim to increase domain understanding, model comprehension and modeling efficiency. In particular, the principle of Perceptual Discriminability, which discusses the visual differences of modeling constructs, reveals potential for model comprehension if human attention is influenced in a way that important modeling constructs are more easily detected, and can hence faster be processed. Yet, so far no conditions how the human gaze can be influenced have been defined and evaluated for Conceptual Modeling. This dissertation extends Perceptual Discriminability for conditions to attract human attention for those constructs that are important for model comprehension. Furthermore, these conditions are applied to constructs of two different modeling grammars in general as well as to elements of the process flow of Business Process Models. To evaluate the results a laboratory experiment of extended Perceptual Discriminability is described in which significant differences have been identified for process flow comprehension. For the demonstration of the potential of extended Perceptual Discriminability BPMN secondary notation is improved by emphasizing those constructs that are most important for model comprehension. Therefore, those constructs that are important for model comprehension have been identified within a content analysis and have been worked on according to the conditions of extended Perceptual Discriminability for those visual variables that are free for an application in secondary notation.

Streets are the most resilient elements in a city. While buildings are replaced and property borders redrawn, the streets remain. The primary means of planning new streets and the built environment surrounding it is by the creation of a two-dimensional plan - in a Swedish context called a detailed development plan. The two-dimensional plan is sometimes criticized for its inability to take the three-dimensional world into account and thus its inability to predict the actual outcome of the plan. To address this critique and provide additional understanding for this planning device, this paper empirically explores if the distribution of visual attention can  be predicted from a two-dimensional plan.  Visual attention is explored due to sight being the most prominent means used by humans to gather information in the urban environment. Fifteen subjects performed a simple, computerized eye-tracking experiment, whereby their visual attention was measured as they looked at 40 images on a monitor. The 40 images depicts four different street types: blocked, open, curved and angled, each of which was represented with a simple figure image, as per interpretation from a two-dimensional plan, as well as a photograph of the same environment, representing the actual outcome of the plan. The results show that the simple figure images have effective predictive capabilities, as  the distribution of visual attention exhibited a similar pattern in both the figure image and the photograph. The results also show that different patterns of visual attention are evoked by each of the four different street types. In sum, the results indicate that two-dimensional plans are able to predict the future three-dimensional outcome of a given plan in terms of visual attention. These indications are valuable for planners, architects, engineers and decision-makers when planning for new urban environments. The results are also valuable for understanding human perception of streets in a wider context.

Le contrôle aérien doit faire face à une forte intensification du trafic aérien. Dans cette situation, la problématique de la charge mentale chez les contrôleurs aériens est une préoccupation majeure pour maintenir le niveau de sécurité actuel. Le système d’aide automatisé ERASMUS a été élaboré afin de réduire la charge mentale chez les contrôleurs aériens. L’objectif d’ERASMUS est de compenser les effets liés à l’intensification du trafic en réduisant de manière subliminale la charge mentale associée à l’augmentation des conflits potentiels. L’objectif principal de cette thèse est de proposer pour la première fois une mesure objective de l’impact du système d’aide ERASMUS sur la charge mentale des contrôleurs aériens. La réalisation de cet objectif a nécessité le développement d’une plateforme originale d’enregistrement et de traitement des mouvements oculaires non intrusive dans un environnement de simulation hautement fidèle. Les mouvements oculaires d’un groupe de contrôleurs aériens experts ont été enregistrés. En accord avec l’hypothèse d’ERASMUS, les résultats ont montré des effets de tailles moyennes à grandes sur l’amplitude des saccades, le temps moyen passé sur les aéronefs et sur la distribution de l’attention allouée à la scène visuelle. De plus, sans ERASMUS, l’augmentation de la densité du trafic a augmenté de manière significative les diamètres pupillaires. A l’opposé, quand ERASMUS est actif, l’intensification du trafic n’a pas impacté significativement les diamètres pupillaires. Nous discutons l’impact d’ERASMUS sur la charge mentale ainsi que l’utilisation des mesures oculométriques dans un environnement de simulation écologique de contrôle aérien. / Air Traffic Control has to handle the strong and constant increase in air traffic density. In this context, mental workload experienced by air traffic controllers is a key research concept to maintain the actual safety level. ERASMUS is an automated aid system designed to reduce air traffic controllers’ workload. The purpose of ERASMUS is to compensate the effects of the air traffic growth by reducing the increased mental workload associated with a greater number of potential conflicts. Prior experiments designed to validate the ERASMUS system showed a reduction in ratings of mental workload, but only subjectives measures were used. In the present thesis, the first goal is to complete these first results by providing, for the first time, a real time objective measure of controllers’ mental workload. In this purpose, we had to develop a new non-intrusive eye-tracking platform in a fully realistic simulation environment. The eye movements of seven controllers, placed in a high-fidelity simulation, were recorded. Traffic sequences were manipulated (with vs. without ERASMUS). Consistent with a reduced workload hypothesis, results showed medium to large effects of ERASMUS on the amplitude of saccades, on the time spent gazing aircraft, and on the distribution of attention over the visual scene. Moreover, without ERASMUS, growth in the traffic density significantly increased pupil diameters. In contrast, when ERASMUS was activated, traffic density growth did not impact significantly pupil diameters. Finally, we discuss the impact of ERASMUS on mental workload and the use of pupillometric measures in an ecological air traffic control environment.