Qui n’a jamais souhaité avoir des yeux derrière la tête ? Cette thèse propose d’étudier l’extension du champ visuel humain, que ce soit dans le monde réel ou dans un environnement virtuel. Nous avons d’abord conçu FlyVIZ, un dispositif qui permet d’augmenter le champ visuel. Il est composé d’une caméra catadioptrique, d’un visiocasque et d’un algorithme de traitement d’image. Lorsqu’un utilisateur porte ce dispositif, il dispose d’une vue à 360 degrés de son environnement. Le prototype a été testé avec succès dans différents scenarios, comme attraper un objet tendu dans le dos sans tourner la tête, ou passer des portes en marchant à reculons. Ensuite nous avons proposé une nouvelle méthode pour le rendu d’environnements virtuels, avec un champ visuel étendu, et en temps réel. Pour résoudre les problèmes dus à l’utilisation de projections non planes, nous avons ajouté une nouvelle étape dans le pipeline graphique. Notre méthode a ensuite été adaptée au rendu stéréoscopique avec un champ visuel de 360°. Nous avons mené une évaluation préliminaire sur l’utilisation d’un champ visuel étendu appliqué à une tache de navigation dans des environnements virtuels. Nos résultats semblent confirmer que l’utilisation d’un champ visuel étendu permet une navigation plus efficace, en diminuant le temps moyen pour effectuer une tache. Parmi les différentes projections non planes testées, une préférence pour les projections équirectangulaire et de Hammer a été exprimée. Nous avons également traité le problème de conflit d’indice de profondeurs rencontré dans les images stéréoscopiques lorsqu’un objet affiché en parallaxe négative est partiellement occulté par un bord du support d’affichage. Nous avons proposé SCVC (Stereoscopy Compatible Volume Clipping, le découpage de la scène selon le volume compatible avec la stéréoscopie) pour résoudre ce problème en n’affichant que la partie de l’espace qui n’est pas sujette au conflit d’indice de profondeur. La méthode a été évaluée et les résultats ont montrés que SCVC améliore significativement la perception de la profondeur et que les utilisateurs expriment une préférence pour cette méthode. L’extension du champ visuel humain ouvre de nouvelles perspectives pour l’exploration ou la surveillance de l’environnement d’un utilisateur. Cette extension pourrait bénéficier à diverses applications, que ce soit dans le contexte d’un environnement réel ou virtuel. Pour la sécurité des personnes ou la défense, des pompiers, des policiers ou des soldats pourraient tirer avantage d’un champ visuel étendu. Ce type de visualisation peut également profiter à l’exploration rapide d’environnements virtuels ou à la recherche d’objet dans ces derniers. / Who have never wanted to have eyes in the back of his head? This doctoral thesis proposes to study the extension of the human field-of-view (FoV) in both real and virtual environments. First we have designed FlyVIZ, a new device to increase the human FoV. It is composed of a helmet, combining a catadioptric camera, a HMD and an image processing algorithm. Wearing this device allows a user to experience 360° vision of its surroundings. The prototype is demonstrated through scenarii such as grasping an object held out behind their back without turning their head or walking backward through doorways. Then we have proposed a novel method to render virtual environments with wide FoV in real-time. To solve the rendering issue induced by usage of non-planar projections, we introduce a special stage in real-time rendering pipeline. Our method was then adapted for real-time stereoscopic rendering with 360° FoV. We have conducted a preliminary evaluation of real-time wide FoV rendering for a navigation task in virtual reality. Our results confirm that using a wide FoV rendering method could lead to more efficient navigation in terms of average task completion time. Among the different tested non-planar projection methods, the subjective preference is given to equirectangular and Hammer projections. We also address the problem of frame cancellation, generated by the conflict between two depth cues: stereo disparity and occlusion with the screen border. We have proposed the Stereoscopy Compatible Volume Clipping (SCVC), solving the problem by rendering only the part of the viewing volume free of disparity - frame occlusion conflict. The method was evaluated and results have shown that SCVC notably improved users’ depth perception and that the users expressed preference for SCVC. Wide FoV opens novel perspectives for environments exploration or monitoring. Therefore, it could benefit to several applications, both in real world context or virtual environments. In safety and security applications, firemen, policemen or soldiers could take advantage of wide FoV. Performance of searching task and fast exploration in virtual environments could also be improved with wide FoV.

The aim of this project is to implement a Radio Controlled (RC) car with a Light Detection and Ranging (LiDAR) sensor and a stereoscopic camera setup based on the Robot Operating System (ROS) to conduct Simultaneous Localization and Mapping (SLAM). The LiDAR sensor used is a 2D LiDAR, RPlidar A1, and the stereoscopic camera setup is made of two monocular cameras, Raspberry Pi Camera v2. The sensors were mounted on the RC car and connected using two Raspberry Pi microcomputers.  The 2D LiDAR sensor was used for two-dimensional mapping and the stereo vision from the camera setup for three-dimensional mapping. RC car movement information, odometry, necessary for SLAM was derived using either the LiDAR data or the data from the stereoscopic camera setup. Two means of SLAM were implemented both separately and together for mapping an office space. The SLAM algorithms adopted the Real Time Appearance Based Mapping (RTAB-map) package in the open-source ROS.    The results of the mapping indicated that the RPlidar A1 was able to provide a precise mapping, but showed difficulty when mapping in large circular patterns as the odometry drift resulted in the mismatch of the current mapping with the earlier mapping of the same positions and secondly in localization when turning quickly. The camera setup derived more information about surrounding and showed more robust odometry. However, the setup performed poorly for the mapping of visual loop closures, i.e., the current mapping did not match the earlier mapping of earlier visited positions.

Indiana University-Purdue University Indianapolis (IUPUI) / Despite growing recognition as a significant natural resource, methods for accurately estimating urban tree canopy cover extent and change over time are not well-established. This study evaluates new methods and data sources for mapping urban tree canopy cover, assessing the potential for increased accuracy by integrating high-resolution satellite imagery and 3D imagery derived from LIDAR and stereoscopic sensors. The results of urban tree canopy classifications derived from imagery, 3D data, and vegetation index data are compared across multiple urban land use types in the City of Indianapolis, Indiana. Results indicate that incorporation of 3D data and vegetation index data with high resolution satellite imagery does not significantly improve overall classification accuracy. Overall classification accuracies range from 88.34% to 89.66%, with resulting overall Kappa statistics ranging from 75.08% to 78.03%, respectively. Statistically significant differences in accuracy occurred only when high resolution satellite imagery was not included in the classification treatment and only the vegetation index data or 3D data were evaluated. Overall classification accuracy for these treatment methods were 78.33% for both treatments, with resulting overall Kappa statistics of 51.36% and 52.59%.

The chemical resistance of glass is an important property for many applications. This property has been extensively studied for many types of glass under static conditions (no liquid is removed during the experiment). There has been little research conducted on the effects of additional stimuli on the dissolution of glass. For this research lithium disilicate was leached in deionized water at multiple temperatures while microwave radiation, ultrasonication or flow conditions were also applied to the system. These results were then compared to static baseline to determine if these stimuli would cause any change to the mechanisms and kinetics of the reaction. It was determined that for the experimental conditions used there was little to no change in dissolution when 2.45 GHz microwave radiation instead of conventional methods was used to heat the reaction. Results from ultrasonication found that samples that experienced erosion showed an increase in dissolution with an increase in dissolution following heavier erosion. This was thought to be due to both an increase in the surface area of the sample to volume of solution (SA/V) ratio (erosion would modify the surface area and release small particulates) and the accelerated removal of the depleted layer due to erosion. Stereoscopic reconstruction was used to semi-quantitatively measure the change in surface area. Regions that experienced minor erosion showed a 3-6% increase in surface area while those that experienced heavy erosion showed a 29-35% increase in surface area. Due to inconsistencies in the size of the eroded area it was not possible to determine the effects of power intensity with this research. Flow dissolution showed similar trends in concentration and different trends for the total normalized mass loss (TNL) to previously published research on more complex glasses. The elemental concentration initially increased before reaching a peak and decreasing to steady state. This peak was thought to be caused by the combination of flow, increasing thickness in the depleted layer, and an initial fluctuation in the forward reaction rate due to changes in pH. For the lithium disilicate glass used in this research both the elemental concentration and the TNL increased with increasing temperature and decreasing flow rate (silica dissolution was an exception as it did not show any change in TNL due to flow). All experimental conditions were shown to achieve steady state (dC/dt~0) by the seventh day of leaching. The contrast in the observed TNL trends between lithium disilicate and more complex glasses was thought to be due to differences in reaction rates and the presence of an additional surface layer in the complex glasses due to precipitation. Microscopy of the leached glass showed that surface features introduced during grinding (scratch lines and microcracks) were preferentially leached and grew in size and number visible during dissolution. A semi-quantitative model was created using stereoscopic reconstruction to describe the preferential leaching of the microcracks as there was little available discussion found in literature outside of associating the growth of these features with localized network dissolution. In this model the microcracks experience preferential dissolution leading to a change in size and shape. The SA/V ratio inside the crack would be much larger than the bulk system (calculated to initially be ~768,000cm-1 compared to the bulk's 0.1cm-1). This would cause massive acceleration in the initial ion exchange, raising the pH of the solution which would in turn cause network dissolution to occur much faster inside the crack. Based on static experiments on lithium disilicate frit (SA/V of 1,010cm-1) the pH inside the crack would jump to above 11 in minutes. As the crack grows, the SA/V ratio inside it would decrease (largest cracks were found to have a ratio ~100,000cm-1). The accelerated leaching caused by these features could have a noticeable effect on the dissolution results. In addition to the accelerated leaching inside a crack, the size of the depleted layer under the crack would be different from the bulk glass. / Doctor of Philosophy / The chemical resistance of glass is an important property for many applications. This property has been extensively studied for many types of glass under static conditions where no liquid was removed and temperature was the major variable. For this research lithium disilicate was leached in deionized water at multiple temperatures while the additional stimuli of microwave radiation, ultrasonication or flow conditions were also applied to the system. The question that this research addressed was how does the aqueous dissolution of glass change when a system is exposed to these additional stimuli? Although glasses are subjected to these stimuli in many everyday applications, their influence on dissolution has not been studied extensively. Lithium disilicate glass was selected because it contains components used in many commercial glasses, has sufficient reactivity in water to allow experiments to be completed in a reasonable time, and because its mechanisms for dissolution under static conditions were well known. Glass is frequently selected to be the container when microwaves are used to heat food or materials. Flow is an important part of many applications involving glass including the storage of nuclear waste glass, glass-lined tanks used in the chemical industries, in the use of glass in the human body (bioglass and dental crowns), and in typical window and laboratory glasses where intermittent aqueous contact and runoff may occur. Examining how cavitation via ultrasonication can be controlled to either minimize or maximize element extraction is important, with the removal of rare earth elements from fly ash being one example.

The Enigma of Appearances is an examination into the medium of three-dimensional photography, with particular focus on the technique of stereoscopy. Invented in the mid-Victorian era, stereoscopy was an attempt to simulate natural three-dimensional perception via a combination of optics, neurology, and a pair of dissimilar images. Whilst successful in producing a powerful illusion of spatial depth and tangibility, the illusion produced by stereoscopy is anything but ??natural??, when compared to three-dimensional perception observed with the naked eye. Rather, stereoscopic photography creates a strange and unnatural interpretation of three-dimensional reality, devoid of atmosphere, movement and sound, where figures appear frozen in mid-motion, like waxwork models, or embalmed creatures in a museum. However, it is precisely stereoscopic photography??s unique and enigmatic interpretation of three-dimensional reality, which gives it its strength, separating it from being a mere ??realistic?? recording of the natural world. This thesis examines the unique cultural position that stereoscopy has occupied since its invention in 1838, from its early role as a tool for the study of binocular vision, to its phenomenal popularity as a form of mass entertainment in the second half of the 19th century, to its emergence in contemporary fine art practice in the late 20th and 21stt centuries. Additionally, The Enigma of Appearances gives a detailed analysis of the theory of spatial depth perception; it discusses the dichotomy between naturalia versus artificialia in relation to stereoscopic vision; and finally, traces the development of experimental studio practice and research into stereoscopic photography, undertaken for this MFA between 2005 and 2007. The resulting work, Camera Mortuaria (Italian for ??Mortuary Room??), is a powerful and innovative series of anaglyptic portraits, based upon an experimental stereoscopic technique that enables the production of extreme close-up three-dimensional photography. Applying this technique to the reproduction of the human face in three-dimensional form, Camera Mortuaria presents a series of ??photo sculptures??, which hover between reality and illusion, pushing the boundaries of stills photography to the limit, and beyond.

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The Enigma of Appearances is an examination into the medium of three-dimensional photography, with particular focus on the technique of stereoscopy. Invented in the mid-Victorian era, stereoscopy was an attempt to simulate natural three-dimensional perception via a combination of optics, neurology, and a pair of dissimilar images. Whilst successful in producing a powerful illusion of spatial depth and tangibility, the illusion produced by stereoscopy is anything but ??natural??, when compared to three-dimensional perception observed with the naked eye. Rather, stereoscopic photography creates a strange and unnatural interpretation of three-dimensional reality, devoid of atmosphere, movement and sound, where figures appear frozen in mid-motion, like waxwork models, or embalmed creatures in a museum. However, it is precisely stereoscopic photography??s unique and enigmatic interpretation of three-dimensional reality, which gives it its strength, separating it from being a mere ??realistic?? recording of the natural world. This thesis examines the unique cultural position that stereoscopy has occupied since its invention in 1838, from its early role as a tool for the study of binocular vision, to its phenomenal popularity as a form of mass entertainment in the second half of the 19th century, to its emergence in contemporary fine art practice in the late 20th and 21stt centuries. Additionally, The Enigma of Appearances gives a detailed analysis of the theory of spatial depth perception; it discusses the dichotomy between naturalia versus artificialia in relation to stereoscopic vision; and finally, traces the development of experimental studio practice and research into stereoscopic photography, undertaken for this MFA between 2005 and 2007. The resulting work, Camera Mortuaria (Italian for ??Mortuary Room??), is a powerful and innovative series of anaglyptic portraits, based upon an experimental stereoscopic technique that enables the production of extreme close-up three-dimensional photography. Applying this technique to the reproduction of the human face in three-dimensional form, Camera Mortuaria presents a series of ??photo sculptures??, which hover between reality and illusion, pushing the boundaries of stills photography to the limit, and beyond.

3D user interface technologies have the potential to make games more immersive & engaging and thus potentially provide a better user experience to gamers. Although 3D user interface technologies are available for games, it is still unclear how their usage affects game play and if there are any user performance benefits. A systematic study of these technologies in game environments is required to understand how game play is affected and how we can optimize the usage in order to achieve better game play experience. This dissertation seeks to improve the gaming experience by exploring several 3DUI technologies. In this work, we focused on stereoscopic 3D viewing (to improve viewing experience) coupled with motion based control, head tracking (to make games more engaging), and faster gesture based menu selection (to reduce cognitive burden associated with menu interaction while playing). We first studied each of these technologies in isolation to understand their benefits for games. We present the results of our experiments to evaluate benefits of stereoscopic 3D (when coupled with motion based control) and head tracking in games. We discuss the reasons behind these findings and provide recommendations for game designers who want to make use of these technologies to enhance gaming experiences. We also present the results of our experiments with finger-based menu selection techniques with an aim to find out the fastest technique. Based on these findings, we custom designed an air-combat game prototype which simultaneously uses stereoscopic 3D, head tracking, and finger-count shortcuts to prove that these technologies could be useful for games if the game is designed with these technologies in mind. Additionally, to enhance depth discrimination and minimize visual discomfort, the game dynamically optimizes stereoscopic 3D parameters (convergence and separation) based on the user's look direction. We conducted a within subjects experiment where we examined performance data and self-reported data on users perception of the game. Our results indicate that participants performed significantly better when all the 3DUI technologies (stereoscopic 3D, head-tracking and finger-count gestures) were available simultaneously with head tracking as a dominant factor. We explore the individual contribution of each of these technologies to the overall gaming experience and discuss the reasons behind our findings. Our experiments indicate that 3D user interface technologies could make gaming experience better if used effectively. The games must be designed to make use of the 3D user interface technologies available in order to provide a better gaming experience to the user. We explored a few technologies as part of this work and obtained some design guidelines for future game designers. We hope that our work will serve as the framework for the future explorations of making games better using 3D user interface technologies.

Ce mémoire de thèse traite de la mise en correspondance d'images pour des applications de vision stéréoscopique ou de stabilisation d'images de caméras vidéo. les méthodes de mise en correspondance reposent généralement sur l'utilisation de points d'intérêts dans les images, c'est-à-dire de points qui présentent de fortes discontinuités d'intensité lumineuse. Nous présentons tout d'abord un nouveau descripteur de points d'intérêt, obtenu au moyen d'un filtre anisotropique rotatif qui délivre en chaque point d'intérêt une signature mono-dimensionnelle basée sur un gradient d'intensité. Invariant à la rotationpar construction, ce descripteur possède de trés bonnes propriétés de robustesse et de discrimination. Nous proposons ensuite une nouvelle méthode d'appariement invariante aux transformations euclidiennes et affines. Cette méthode exploite la corrélation des signatures sous l'hypothèse de faibles déformations, et définit une mesure de distance nécessaire à l'appariement de points. Les résultats obtenus sur des images difficiles laissent envisager des prolongements prometteurs de cette méthode. / This thesis adresses the issue of image matching for stereoscopic vison applications and image stabilization of video cameras. Methods of mapping are generally based on the use of interest points in the images, i.e. of points which have strong discontinuities in light intensity. We first present a new descriptor of points of interest, obtained by means of an anisotropic rotary filter which delivers at each point of interest a one-dimensional signature based on an intensity gradient. Invariant to rotation by construction, thisdescriptor has very good properties of robustness and discrimination. We then propose a new matching method invariant to Euclidean and affine transformations. This method exploits the correlation of the signatures subject to moderate warping, and defines a distance measure, necesssary for the matching of points. the results obtained on difficult images augur promising extentions to this method.

Ce travail porte sur l’étude de l’évolution morphologique dans la zone de swash à haute résolution spatiale et temporelle afin de pouvoir analyser l’influence de la houle. Cette étude s’appuie sur deux campagnes de mesures menées dans le grand canal à houle CIEM (Barcelone), l’une avec application d’un forçage aléatoire érosif de type JONSWAP et l’autre avec application d’une série de forçages bichromatiques. L’originalité de l’étude proposée ici consiste en l’analyse, par une méthode de stéréoscopie optique, de l’évolution du fond avec une excellente précision tout en quantifiant précisément l’évolution des fronts d’eau sur une surface continue, la majorité des techniques de mesure ne donnant en général accès qu’à des relevés ponctuels dans cette zone. La position du lit de sable est estimée avec une précision de quelques centaines de μm. Sur des temps longs, le forçage JONSWAP érosif engendre un recul global et quasi-homogène dans la zone de swash. Cependant, cette évolution ne semble pas influencer la réponse hydrodynamique qui reste similaire dans la zone de swash lorsque l’on répète la série. Ceci a été confirmé dans le cas des forçages bichromatiques, répétés sur des fonds différents. Au sein d’une série d’un forçage aléatoire, différentes échelles de temps sont observées : l’échelle gravitaire (période caractéristique du signal) et les ondes infragravitaires (large gamme d’événements plus longs). Cette coexistence de plusieurs échelles de temps a pu être associée à la forte variabilité du profil de plage, notamment dans la direction cross-shore. Le cas bichromatique montre quant à lui une convergence du profil de plage vers un état qui ne dépendrait que du forçage en entrée. L’interaction d’une seule onde infragravitaire avec l’onde gravitaire ne peut donc pas être responsable de la variabilité du fond observée avec le forçage aléatoire. En revanche, cette étude semble confirmer la présence d’événements particuliers à l’origine d’une forte modification du fond sableux. Le lien entre ces événements et l’interaction entre des événements hydrodynamiques spécifiques et la forme du fond n’est pas encore complètement établi. Enfin, pour le forçage aléatoire la variabilité transverse induite par les ondes courtes est forte alors qu’elle semble plus faible à l’échelle de l’onde longue. Pour le forçage bichromatique, cette variabilité transverse a également pu être observée mais son lien avec le forçage reste encore à élucider. / This study investigates the morphological evolution in the swash zone at high spatial and temporal resolution to be able to analyze the swell influence. The study is here based on two measurement campaigns in the large CIEM wave flume (Barcelona), using both a random erosive JONSWAP and bichromatics forcing. The originality of the proposed study lies on analysis, by an optical stereoscopic method, of bottom evolution with a very good precision while getting an accurate quantification of water fronts evolution on a continuous area, most of the measurement techniques generally allowing only to obtain punctual measurements in this area. The sand bed position is estimated with an accuracy of a few hundred μm. Over long periods, erosive JONSWAP forcing generates an overall and almost homogeneous backward movement in the swash area. However, this trend does not appear to influence the hydrodynamics response that remains similar in the swash area when the series is repeated. This was confirmed in the bichromatic forcings case, repeated on different bottoms. During a random forcing series, different time scales are observed : the gravity scale (characteristic period of the signal) and infragravity waves (wide range of longer events). This coexistence of several time scales could be associated with the observation of a strong variability of the beach profile, especially in the cross-shore direction. The bichromatic case shows meanwhile convergence of beach profile to a state that would depend only on forcing conditions. The interaction of a single infragravity wave with the gravitational wave can therefore not be responsible for the observed bottom variability with the random forcing. In contrast, the present study seems to confirm the presence of specific events responsible of a strong change in the sandy bottom. The link between these events and the hydrodynamic interaction between specific events and the bottom shape is not yet completely established. Finally, for the random forcing the transverse variability induced by short wave is strong as it seems weak at long wave time scale. For bichromatic forcing, the transverse variability has also been observed but its link with the forcing still remains to be elucidated.