Dissertationen zum Thema „Real-time 3D visual simulation“

Performance is something that is always of concern when developing real-time 3D graphics applications. The way programs are made today with object-oriented programming has certain flaws that are rooted in the methodology itself. By exploring different programming paradigms we can eliminate some of these issues and find what is best for programming in different areas. Because real-time 3D applications need high performance the data-oriented design paradigm that makes the data the center of the application is experimented with. By using data-oriented design we can eliminate certain issues with object-oriented programming and deliver improved applications when it comes to performance, flexibility, and architecture. In this study, an experiment creating the same type of program with the help of different programming paradigms is made to compare the performance of the two. Some additional up- and downsides of the paradigms are also mentioned

Det finns övrigt digitalt material (t.ex. film-, bild- eller ljudfiler) eller modeller/artefakter tillhörande examensarbetet som ska skickas till arkivet.

While many games incorporate physics to simulate different aspects of gameplay, this is uncommon when it comes to fluid flows like wind, due to the complexity of the associated equations. The challenge increases in 3-dimensional worlds with large world maps and a real-time simulation. It is however possible to simplify a simulation by prioritizing visual and gameplay effects rather than physical accuracy, while still using a physically-sound system as a base. What this means for each game will differ depending on the architecture of the game, the desired outcome and acceptable performance costs. This paper addresses the implementation of a real-time, grid-based wind simulation in Rust for the game Veloren. A preliminary implementation with a simple graphical output was used before the simulation was integrated with the game. In Veloren, the resulting implementation is primarily server-based with a windsim system that runs the simulation itself, while the client side receives updates for the player's position, allowing the player to fly with a handglider using the wind currents created by the simulation. The performance cost of the implementation was measured for both the server and the client, using frames per second according to the grid size (space resolution) and how often the simulation is run (time resolution). When compared to the baseline before the implementation, it showed a performance cost for the server that increased with the time and space resolution. For the client side, no detectable performance cost was observed, but a lower simulation frequency resulted in sharp changes in wind direction from the player's perspective. Given that many options for optimization exist which were not systematically explored, the results show promise for the feasibility of this type of simulation in Veloren by expanding the current implementation.

With a focus of always being connected, it's become typical for laptops and mobile devices to include multiple wireless network devices. Though the additional network devices have created mobility and versatility of how a user is connected, it is common for only one to be active at any given time. While likely that new mesh protocols will help maximize connectivity and power consumption by utilizing lower-power multi-hop techniques, it is still difficult to visualize these protocols due to the complexity created by each node's simple choices. Further challenges are presented by the variety of network devices which share frequency ranges with different output power, sensitivities, and antenna radiation patterns. Due to the complexity of these configurations and environments, it becomes clear that reproducible simulations are required. While several network simulators have been thoroughly tested over their many years of use, they often lack realistic handling of key factors that affect wireless networks. A few examples include cross-channel interference, propagation delays, interference caused by nodes beyond communication range, channel switching delays, and non-uniform radiation patterns. Another key limitation of these past tools is their limited methods for clearly displaying characteristics of multi-channel communication. Furthermore, these past utilities lack the graphical and interactive functions which promote the discovery of edge cases through the use of human intuition and pattern recognition. Even with their other limitations, many of these simulators are also extendable with new components and simulation abilities. As a result, a large set of protocols and other useful discoveries have been developed. While the concepts are well tested and verified, a new challenge is found when moving code from prototype to production due to code portability problems. Due to the sophistication of these creations, even small changes in code during a protocols release can have dramatic effects on its functionality. Both to encourage quicker development cycles and maintain code validation, it would be advantageous to provide simulation interfaces which directly match that of production systems. To overcome the various challenges presented and encourage the use of innate human abilities, this paper presents a novel simulation framework, Network Channel Visualizing Simulator (NCVS), with a real-time, interactive, 3D environment with clear representation and simulation of multi-channel RF communication through multiple network device types.

L'avènement de l'imagerie médicale et de nouvelles techniques opératoires a bouleversé les méthodes de travail des médecins. Mais ce changement nécessitera une formation renforcée des praticiens et chirurgiens. C'est pourquoi le dévelopment d'outils appropriés comme les simulateurs médico-chirurgicaux se fait de plus en plus ressentir. Dans ce cadre, nous nous sommes intéressés au problème de la modélisation des phénomènes de déformation de tissu biologique et à la détection des collisions dans un environment virtuel. Dans un premier temps, nous présentons les différents modèles physiques existants et les différentes méthodes de résolution numérique associées aux objets déformable. Nous proposons ensuite un modèle développé pour la simulation de tissu biologique, en présentant successivement les aspects liés à la formulation du modèle, à la résolution du modèle, et au traitement des interactions physiques. Ce modèle, basé sur l'utilisation du principe de Pascal, permet de modéliser de manière relativement satisfaisante des corps biologiques, tout en permettant une simulation interactive. Dans un deuxième temps, nous présentons les différents algorithmes existants pour la détectionde collision, ainsi que la difficulté d'adapter ces algorithmes aux simulateurs médicaux où les objets déformables complexes forment la base du modèle. Nous proposons ensuite les algorithmes développés pour traiter ce problème dans le cadre des simulateurs médicaux. Ces algorithmes présentent des caractéristiques de robustesse numérique et d'efficacité supérieures á l'existant, et permettent de traiter des corps déformables. Nous appliquons ces résultats dans le cadre de deux simulateur medicaux

International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California
Unmanned Aerial Vehicles (UAV) are becoming a significant asset to the military. This has given rise to the development of the Vehicle Control and Simulation System (VCSS), a low-cost ground support and control system deployable to any UAV testing site, with the capability to support ground crew and pilot training, real-time telemetry simulation, distribution, transmission and reception, mission planning, and Global Positioning System (GPS) reception. This paper describes the development of the VCSS detailing its capabilities, demonstrating its use in the field, and showing its novel use of internet technology for vehicle control telemetry distribution.

This thesis explores the balance between visual quality and the performance of a 3D object for computer games. Additionally, it aims to help new 3D artists to create assets that are both visually adequate and optimized for real-time rendering. It further investigates the differences in the judgement of the visual quality of thosethat know computer graphics, and thosenot familiar with it. Many explanations of 3D art optimization are often highly technical and challenging for graphic artists to grasp. Additionally, they regularly neglect the effects of optimization to the visual quality of the assets. By testing several 3D assets to measure their render time while using a survey to gather their visual assessments, it was discovered that 3D game art is very contextual. No definite or straightforward way was identified to find the balance between art quality and performance universally. Neither when it comes to performance nor visuals. However, some interesting findings regarding the judgment of visual quality were observed and presented.
Den här uppsatsen utforskar balansen mellan visuell kvalitéoch prestanda i 3D modeller för spel. Vidare eftersträvar den att utgöra ett stöd för nya 3D-modelleingskonstnärer för att skapa modeller som är både visuellt adekvata och optimerade för att renderas i realtid. Dessutom undersöks skillnaden mellan omdömet av den visuella kvalitén mellan de som är bekanta med 3D datorgrafik och de som inte är det. Många förklaringar gällande optimering av 3D grafik är högst tekniska och utgör en utmaning för grafiker att förståsig på och försummar dessutom ofta effekten av hur optimering påverkar resultatet rent visuallet. Genom att testa ett flertal 3D modeller, mäta tiden det tar för dem att renderas, samt omdömen gällande visuella intryck, drogs slutsatsen att bedömning av 3D modellering för spel är väldigt kontextuell. Inget definitivt och enkelt sätt att hitta balansen mellan visuella kvalitén upptäcktes. Varken gällande prestanda eller visuell kvalité. Däremot gjordes några intressanta upptäckter angående bedömningen av den visuella kvalitén som observerades och presenterades.

Ever since we were children the phrase â In case of an emergency, walk, DONâ T run, to the nearest exitâ has been drilled into our heads. How to evacuate a large number of people from a given area as quickly and safely as possible has been a question of great importance since the first congregation of man; a question that has yet to be optimally answered. There have been many attempts at finding an answer and many more yet to be made. In light of recent world events, 9/11 for instance, the need for a better answer is apparent. While finding a solution to this problem is the end objective, the goal of this thesis is to develop an application or tool that will aid in the search of an answer to this problem. There are several aspects of traditional evacuation plans that make them inherently suboptimal. First among these is that they are static by nature. When a building is designed, there is some care taken in analyzing its floor plan and finding an optimal evacuation route for everyone. These plans are made under several assumptions and with the obvious constant that they cannot be modified during the actual emergency. Yes, it is possible for such a plan to actually end up being the optimal plan during any given evacuation, but the likelihood of this being the case is most definitely less then 100%. There are many reasons for this. The most obvious is this: the situation that the plan is trying to solve is a very dynamic one. People will not be where they should be or in the quantities that the static plan was prepared for. Many of them will probably not know what they should do in an emergency and so most likely will follow any large group of people, like lemmings. Finally, most situations that require the evacuation of a building or area occur because all or part of the building has become, or is becoming, unsafe. It is impossible for a static evacuation plan to take into account the way a fire or poisonous gas is spreading, or the state of the structural stability of the building. What is needed during a crisis is an artificially intelligent and dynamic evacuation system that is capable of (1) analyzing the state of the building and its occupants, (2) coming up with a plan to get everyone out as fast as possible, and (3) directing all occupants along the best exit routes. Furthermore, the system should be able to modify its plan as the evacuation progresses. This application is intended to provide researchers in this area the means to quickly and accurately simulate different evacuation theories and ideas. That being the case, it will have powerful graphical capabilities, thus allowing the researchers to easily see the real-time results of their work. It will be able to use diverse modeling techniques in order to handle the many different ways of approaching this problem. It will provide a simple way for equations and mathematical models to be entered which can affect the behavior of most aspects of the world being simulated. This work is in conjunction with, and closely tied to, Dr Pushkin Kachrooâ s research on this same topic. The application is designed so that future developers can quickly add to and modify its design to meet their specifications. It is not the goal of this work to provide an application that directly solves the optimal evacuation problem, or one that inherently simulates everything perfectly. It is the job of the researchers using this application to define the specific physics equations and models for each component of the simulation. This application provides an easy way to add these definitions into the simulation calculations. In brief, this Escape Simulator is a client server application. All of the graphics and human interaction are handled client side using Win32 and Direct3D. The actual simulation world calculations are handled server side, and both the client and server communicate via DirectPlay. The algorithm being used to model the objects and world by the server will be completely configurable. In fact, everything in the world, including the world physics, will be completely modifiable. Though the researchers will need to write the necessary pluggins that to define the actual models and algorithms used by the agents, objects, and world, ultimately this will give them much more power and flexibility. It will also allow for third parties to develop libraries of commonly used algorithms and resources that the researchers can use. This research was supported in part from the National Science Foundation through grant no. CMS-0428196 with Dr. S. C. Liu as the Program Director. This support is gratefully acknowledged. Any opinion, findings, and conclusions or recommendations expressed in this study are those of the writer and do not necessarily reflect the views of the National Science Foundation.
Master of Science

Data loss has always been a side effect of sharing 3D models between different CAD systems. Continuous research and new frameworks have been implemented to minimise the data loss in CAD and in other downstream applications separately like 3D visual graphics applications (eg. 3DS Max, Blender etc.). As a first step into this research area, the thesis is an explorative study on understanding the problem of CAD data loss while exchanging models between a CAD application and a visual application. The thesis is performed at Tacton systems which provides product configurations to their customers in both CAD and visual environments and hence the research is focussed on reusing the CAD data in visual applications or restoring the data after exchange. The research questions are framed to answer the reasons of data loss and address the possible implementation techniques at the company. Being a niche topic, the thesis required inputs from different perspectives and knowledge sharing from people outside the company which proves the significance of open innovation in technology-oriented companies. Ten different ideas were brainstormed and developed into concepts to solve the problem of data loss. All the concepts are analysed and evaluated to check the functionality and feasibility of implementing it within the company workflow. The evaluations resulted in different concepts that are capable of solving the research problem. They have also been verified with various people internal and external to the company. The results also highlight the strengths and weaknesses of each of these concepts giving clear instructions to the company on the next steps.
Dataförluster har alltid varit en följd av att dela 3D-modeller mellan olika CAD-system. I forskning har nya metoder utvecklats och implementerats för att minimera dataförlusten i CAD och andra program, som t.ex. visuella 3D-grafikapplikationer (3DS Max, Blender etc.). Denna rapport är resultatet av en studie kring CAD-dataförluster när man överför modeller mellan ett CAD-program och ett visualiseringsprogram. Studien har utförts vid Tacton Systems AB, som tillhandahåller produktkonfigureringslösningar både i CAD-program och i visuella miljöer och därför har studien haft fokus på att återanvända eller återskapa CAD-data i visualiseringsprogramvaror. Forskningsfrågorna är inriktade på att hitta orsaker till dataförlusterna och möjliga lösningar för företaget. Eftersom detta är ett högspecialiserat ämne krävde arbetet insatser från olika perspektiv och kunskapsinhämtning från människor också utanför företaget, vilket visar på betydelsen av öppen innovation i teknikorienterade företag. Tio olika idéer togs fram och utvecklades till koncept för att lösa problemet med dataförluster. Alla koncept har analyserats och utvärderats för att bedöma deras funktionalitet och genomförbarhet, för att implementera dem inom företagets arbetsflöde. Utvärderingarna resulterade i sex olika koncept som skulle kunna lösa problemet. Dessa koncept har diskuterats och verifierats med olika personer inom och utanför företaget. Resultatet visar styrkor och svagheter i vart och ett av dessa koncept och ger tydliga rekommendationer till företaget om nästa steg.

Les résultats des chirurgies orthopédiques correctrices sont difficilement prévisibles et, malheureusement, parfois infructueux. D’autres maladies résultantes d’un handicap majeur tel que l’escarre sont encore très peu comprises. Malgré une prévalence dans la population conséquente, peu d’études ont été menées sur ces thèmes. L’étude volumétrique du muscle en tant que tissu mou actif manque d’informations détaillées. Particulièrement les déformations et raideurs subséquentes aux contractions de muscles à arrangement de fascicules complexes. La modélisation volumétrique des muscles, fournirait un outil puissant pour la simulation personnalisée des contraintes subies par le corps, durant des contactes prolongés ou récurrents avec des dispositifs médicaux standards et inadaptés à la morphologie, mais aussi la planification d’opérations chirurgicales ou de séquences de stimulation électrique fonctionnelle. Il n’existe actuellement aucun logiciel permettant la reconstruction automatique de l’architecture des fascicules, aponévroses et tendons à partir d’acquisitions IRM d’un patient spécifique. La méthode actuelle de modélisation volumétrique du muscle est coûteuse en temps de calcul, donc inefficaces pour des simulations temps-réel du comportement du système musculo-squelettique avec représentation des fonctions physiologiques. Cette thèse est dirigée par les contributions nombreuses qui restent encore à apporter dans le domaine. Les méthodes de modélisation actuelles basées sur la méthode des éléments finis classique sont complexes, manquent de flexibilité ou de précision en temps-réel. Nous proposons une approche multi-modèles basée sur le mapping barycentrique qui découple la fonction de densité d’énergie de déformations du muscle en un ensemble de modèles indépendants de moindre complexité, avec les objectifs suivants : - Améliorer la reconstruction de l’architecture musculaire à partir des acquisitions IRM en terme de complexité et flexibilité. - Séparer la modélisation du muscle en modèles simple et indépendants, de manière à offrir plus de flexibilité, en réduisant la complexité, qui permettront de découpler les résolutions des éléments déformables des éléments actifs du muscle. - En diminuant le nombre d’éléments finis garantissant la cohérence des résultats, nous diminuons le temps de calcul nécessaire à chaque pas de simulation .Nos méthodes s’inspirent des travaux précédents sur la représentation tri-dimensionnelle de la géométrie et l’architecture complexes des muscles de [Blemker and Delp, 2005]. De plus, la définition mathématique est étudiée [Chi et al., 2010] pour caractériser la densité d’énergie de déformations du muscle squelettique. En rapport avec les méthodes précédentes, nous revendiquons les avancées suivantes : - Amélioration de la représentation 3D des muscles de patients spécifiques avec architecture et géométrie complexes, à partir de mesures IRM. La méthode est plus flexible et rapide que les précédentes. - Une nouvelle méthode de modélisation des déformations musculaires via la modélisation découplée des différents tissus musculaires. Cette nouvelle approche permet une définition indépendante des fascicules musculaires, tissus conjonctifs, tendons et aponévroses en gardant une grande précision de déformations. Les performances sont confrontées au rendement de la méthode FEM classique. - Nous atteignons des vitesses de simulation élevées de muscles complexes sur des machines standards par rapport à la FEM. Les performances nous ont permis de simuler en temps-réel la force et les déformations d’un muscle d’individus spécifiques, avec une entrée d’activation actualisée en temps-réel à partir de mesures EMG. - La modélisation d’un muscle nécessite plus de compétence qu’une équipe de recherche peut envisager maitriser. L’approche multi-modèles permet un travail collaboratif, où chaque spécialiste se focalise uniquement sur son domaine de compétence. La modélisation en est extrêmement simplifiée
Corrective orthopedic surgeries results are difficult to be predicted and, unfortunately, sometimes unsuccessful. Other diseases resulting from a motor disability as bedsores are still poorly understood, despite a significant prevalence in the population. However, studies on these topics still insufficient especially for the analysis considering the muscle as a soft tissue volumetric organ. Muscle fascicule architectures and their correlation with movement efficiency is poorly documented, it lack of the detailed information regarding its volumetric deformations and stiffness changes along with muscle contractions.Muscle volumetric modeling, would provide a powerful tool for the personalized accurate simulation of body stresses of disabled or SCI patients during prolonged or friction contacts with standard medical devices non-adapted to particular morphologies, but also the planning of surgeries or functional electrical stimulation sequences.There is currently no software for automatic reconstruction of the architecture of fascicles, aponeurosis and tendons from MRI acquisitions of a specific subject. Actual volumetric muscle modeling is expensive in computational time, and not effective for real-time simulations of musculoskeletal system behavior with representation of physiological functions. The objective of this thesis is directed by the many contributions that have yet to make in the area. The current modeling methods based on the conventional finite element method are complex, inflexible or inaccurate in real-time. We propose a multi-model based on barycentric mapping approach that decouples the muscle strain density energy function into a set of independent less complex models, with the following objectives:- Improve complex muscle architecture reconstruction from the MRI acquisitions in term of complexity and flexibility.- Split muscle modeling into simple independent models, to offer more flexibility and reducing complexity of modeling which allows to have independent resolutions between deformable elements and muscle fiber elements..- By reducing the number of finite elements ensuring consistency of results of force and deformations, we reduce the computation time required for each simulation.Our methods are inspired by the previous work on the three-dimensional representation of the geometry and the complex architecture of muscles [Blemker and Delp, 2005]. In addition, the mathematical definition is studied [Chi et al., 2010] to characterize the energy density of deformations of skeletal muscle.Related with the above methods, we demand the following advances:- Improved three-dimensional representation of specific patients with muscle architecture and complex geometry from MRI measurement for personalized modeling. The method is more flexible and faster than previous.- A novel modeling method for muscle deformation via decoupled modeling of solid and muscle fiber mechanics is established. This new modeling allowed independent definitions between deformable elements and fiber force generation elements while keeping its muscle deformation accuracy. The performance is compared to conventional FEM method. - We reach high computational speed on standard machines for muscle complex simulations compared to FEM. Real-time simulation of specific person’s muscle strain and force is performed with an activation input updated in real-time from surface EMG measures.- Muscle modeling requires interdisciplinary knowledge from different research team members. The multi-model approach allows collaborative work, where each specialist focuses only on its area of expertise thanks to the modular designed modeling

The goal of this project was to evaluate the viability of a mass-spring-damper based model for modeling of biological tissue. A method for automatically generating such a model from data taken from 3D medical imaging equipment including both the generation of point masses and an algorithm for generating the spring-damper links between these points is presented. Furthermore, an implementation of a simulation of this model running in real-time by utilizing the parallel computational power of modern GPU hardware through OpenCL is described. This implementation uses the fourth order Runge-Kutta method to improve stability over similar implementations. The difficulty of maintaining stability while still providing rigidness to the simulated tissue is thoroughly discussed. Several observations on the influence of the structure of the model on the consistency of the simulated tissue are also presented. This implementation also includes two manipulation tools, a move tool and a cut tool for interaction with the simulation. From the results, it is clear that the mass-springdamper model is a viable model that is possible to simulate in real-time on modern but commoditized hardware. With further development, this can be of great benefit to areas such as medical visualization and surgical simulation.
Målet med detta projekt var att utvärdera huruvida en modell baserad på massa-fjäderdämpare är meningsfull för att modellera biologisk vävnad. En metod för att automatiskt generera en sådan modell utifrån data tagen från medicinsk 3D-skanningsutrustning presenteras. Denna metod inkluderar både generering av punktmassor samt en algoritm för generering av länkar mellan dessa. Vidare beskrivs en implementation av en simulering av denna modell som körs i realtid genom att utnyttja den parallella beräkningskraften hos modern GPU-hårdvara via OpenCL. Denna implementation använder sig av fjärde ordningens Runge-Kutta-metod för förbättrad stabilitet jämfört med liknande implementationer. Svårigheten att bibehålla stabiliteten samtidigt som den simulerade vävnaden ges tillräcklig styvhet diskuteras genomgående. Flera observationer om modellstrukturens inverkan på den simulerade vävnadens konsistens presenteras också. Denna implementation inkluderar två manipuleringsverktyg, ett flytta-verktyg och ett skärverktyg för att interagera med simuleringen. Resultaten visar tydligt att en modell baserad på massa-fjäder-dämpare är en rimlig modell som är möjlig att simulera i realtid på modern men lättillgänglig hårdvara. Med vidareutveckling kan detta bli betydelsefullt för områden så som medicinsk bildvetenskap och kirurgisk simulering.

La fissuration à chaud est un défaut majeur rencontré en solidification des alliages d'aluminium. Elle est liée à l'incapacité du liquide de s'écouler dans les zones où des porosités sont présentes, ne permettant pas de les refermer avant qu'elles gagnent en volume. Pour comprendre la fissuration à chaud, il est crucial de développer nos connaissances du comportement mécanique de la zone pâteuse. Pour cela, il est très utile d'effectuer des expériences de microtomographie aux rayons X et des simulations mécaniques sur des volumes élémentaires représentatifs. Dans cette thèse, nous proposons de coupler les deux approches en initialisant une simulation par éléments finis grâce à des données de microtomographie issues d'un test de traction isotherme d'un alliage d'aluminium-cuivre à l'état pâteux. Cette approche originale nous donne directement accès à la réalité expérimentale et permet des comparaisons des évolutions numérique et expérimentale de l'éprouvette. Nous expliquons dans un premier temps comment obtenir la représentation numérique à l'aide de l'algorithme des marching cubes et de la méthode d'immersion de volume. Nous présentons ensuite notre modèle numérique qui s'appuie sur une résolution monolithique des équations de Stokes. Une fois le champ de vitesse obtenu dans l'ensemble des phases solide, liquide et gazeuse, nous utilisons une méthode level set dans un formalisme eulérien afin de faire évoluer la morphologie de notre échantillon numérique. Malgré la simplicité du modèle, les résultats expérimentaux et numériques montrent un accord raisonnable en ce qui concerne la propagation de l'air à l'intérieur de l'échantillon
Hot tearing is a major defect arising during solidification of aluminium alloys. This defect is associated with the inability of liquid to feed areas where voids have started to appear, not allowing to heal small defects before they grow bigger. To understand hot tearing, it is mandatory to develop a good knowledge of the semi-solid mechanical behaviour. It is thus very useful to carry out X-ray microtomographies experiments and mechanical simulations on representative elementary volumes. In this work, we couple the both approaches by initialising a finite element simulation with the help of microtomography data obtained during an isothermal tensile testing of an aluminium-copper alloy in the mushy state. This innovative approach gives a direct access to the experimental reality and allows comparisons of numerical and experimental evolutions of the sample. We explain in a first time how to get the numerical representation thanks to a marching cubes algorithm and the immersed volume method. Then, we present our numerical model for which we solve the Stokes equations in a monolithic way. Once the velocity computed in all the solid, liquid and gaseous phases, we use a level set method in a Eulerian formalism to obtain the morphological evolution of our numerical sample. Despite the model simplicity, numerical and experimental results show a reasonable agreement concerning the air propagation inside the sample

Le système perceptif d’un chirurgien doit s’adapter aux contraintes multisensorielles liées à la chirurgie guidée par l’image. Trois expériences sont conçues pour explorer ces contraintes visuelles et haptiques pour l’apprentissage guidé par l’image. Les résultats montrent que les sujets sont plus rapides et plus précis avec une vision directe. La stéréoscopie 3D n’améliore pas les performances des débutants complets. En réalité virtuelle, la variation de la longueur, largeur, position et complexité de l'objet affecte les performances motrices. La force de préhension appliquée sur un système robotique chirurgical dépend de l'expérience de l'utilisateur. En conclusion, le temps et la précision sont importants, mais la précision doit rester une priorité pour un apprenti. L'homogénéité des groupes d'étude est important pour la recherche sur la formation chirurgicale. Les résultats ont un impact direct sur le suivi des compétences individuelles pour les applications guidées par l'image
Perceptual system of a surgeon must adapt to conditions of multisensorial constrains regard to planning, control, and execution of the image-guided surgical operations. Three experimental setups are designed to explore these visual and haptic constraints in the image-guided training. Results show that subjects are faster and more precise with direct vision compared to image guidance. Stereoscopic 3D viewing does not represent a performance advantage for complete beginners. In virtual reality, variation in object length, width, position, and complexity affect the motor performance. Applied grip force on a surgical robot system depends on the user experience level. In conclusion, both time and precision matter critically, but trainee gets as precise as possible before getting faster should be a priority. Study group homogeneity and background play key role in surgical training research. The findings have direct implications for individual skill monitoring for image-guided applications

Observations of young children are conducted in an educational setting by practitioners to plan and assess activities based on the individual development and needs of the child. Challenges include: recording, how to be an observer rather than a participant, and connecting developmental theory to observable behaviour.Several projects have simulated children in their learning environments, aimed mainly at pre-service teachers, but these have neither been for young children where the activity is play-based nor where the adult is supportive of the child's interests. Some simulations have used 3D graphics to represent a child via a role-playing adult but there have been few attempts to use autonomous characters.A novel real-time interactive 3D graphical simulation—Observation—was developed, providing a physical sandbox for users to: add autonomous characters (representing children), add objects, and customise the play-based environment. The definitions of the characters were informed by the findings from early childhood research. The simulation was evaluated using two complementary serious game frameworks and its utility was evaluated by professionals within the field of early childhood education comprising university students and educators, and local education authority advisors. An explorative, mixed methods approach was taken, triangulating across: a pilot study and a main study; different research instruments (simulation activity plus questionnaire, focus groups, interviews); and a range of participants. The simulation has utility because: it is an interesting way to explore the behaviours of young children, the theoretical understanding behind children's play can be deepened, and observational skills can be developed. The simulation has wide appeal because the perceived utility of the simulation is not influenced by: professional experience, number of real-life observations of young children, or time spent playing video games. Age is considered to be the most important omission from the abstract character in the simulation.

Spark ignited engines are still important for conventional as well as for hybrid power trains and are thus objective to optimization. Today a lot of functionalities arise from software solutions, which have to be calibrated. Modern engine technologies provide an extensive variability considering their valve train, fuel injection and load control. Thus, calibration efforts are really high and shall be reduced by introduction of virtual methods. In this work a physical 0D combustion model is set up, which can cope with a new generation of spark ignition engines. Therefore, at first cylinder thermodynamics are modeled and validated in the whole engine map with the help of a real-time capable approach. Afterwards an up to date turbulence model is introduced, which is based on a quasi-dimensional k-epsilon-approach and can cope with turbulence production from large scale shearing. A simplified model for ignition delay is implemented which emphasizes the transfer from laminar to turbulent flame propagation after ignition. The modeling is completed with the calculation of overall heat release rates in a 0D entrainment approach with the help of turbulent flame velocities. After validation of all sub-models, the 0D combustion prediction is used in combination with a 1D gas exchange analysis to virtually calibrate the modern engine torque structure and the ECU function for exhaust gas temperature with extensive simulations
Moderne Ottomotoren spielen heute sowohl in konventionellen als auch hybriden Fahrzeugantrieben eine große Rolle. Aktuelle Konzepte sind hochvariabel bezüglich Ventilsteuerung, Kraftstoffeinspritzung und Laststeuerung und ihre Optimierungspotentiale erwachsen zumeist aus neuen Softwarefunktionen. Deren Applikation ist zeit- und kostenintensiv und soll durch virtuelle Methoden unterstützt werden. In der vorliegenden Arbeit wird ein physikalisches 0D Verbrennungsmodell für Ottomotoren aufgebaut und bis zur praktischen Anwendung geführt. Dafür wurde zuerst die Thermodynamik echtzeitfähig modelliert und im gesamten Motorenkennfeld abgeglichen. Der Aufbau eines neuen Turbulenzmodells auf Basis der quasidimensionalen k-epsilon-Gleichung ermöglicht anschließend, die veränderlichen Einflüsse globaler Ladungsbewegung auf die Turbulenz abzubilden. Für den Brennverzug wurde ein vereinfachtes Modell abgeleitet, welches den Übergang von laminarer zu turbulenter Flammenausbreitung nach der Zündung in den Vordergrund stellt. Der restliche Brennverlauf wird durch die physikalische Ermittlung der turbulenten Brenngeschwindigkeit in einem 0D Entrainment-Ansatz dargestellt. Nach Validierung aller Teilmodelle erfolgt die virtuelle Bedatung der Momentenstruktur und der Abgastemperaturfunktion für das Motorsteuergerät

L'objectif de cette thèse est de tirer parti d'une illumination totalement ou partiellement contrôlée pour enrichir l'acquisition vidéo de contenus tel que la reconstruction de la forme et de l'apparence. Aujourd'hui de nombreux travaux ont tenté d'atteindre cet objectif. Certains utilisent une illumination contrôlée et séquentielle pour obtenir des reconstructions de haute qualité de la forme et de la réflectance. En revanche, ces méthodes requièrent des dispositifs coûteuses et/ou ne fonctionnent pas en temps réel. Dans cette thèse, nous visions un système d'acquisition à bas coût, rapide et mobile, qui se veut non-seulement le moins intrusif possible mais aussi simple d'utilisation. La première contribution présentée dans cette thèse est une application de la méthode bien connue, intitulée stéréo photométrie, à la vidéo. De plus, comme une fréquence de trame élevée est nécessaire à une telle application, nous proposons une méthode permettant l'utilisation d'une illumination séquentielle avec des caméras rapides de type "electronic rolling shutter". Malgré les résultats intéressants obtenus, la qualité des reconstructions de l'apparence et de la forme n'étaient pas à la hauteur de nos espérances. De plus, la stéréo photométrie est une méthode qui, de nature, n'est pas très adaptée aux applications visées dans cette thèse. Pour notre seconde contribution, nous proposons une méthode de reconstruction de la forme (géométrie) ainsi que de la réflectance diffuse à partir d'une image (d'une séquence) en utilisant un système de capture hybride composé d'un capteur de profondeur (Kinect), d'une caméra grand public et d'un flash. L'objectif est de montrer qu'en combinant une acquisition RGB-D (image couleur + profondeur) avec illumination séquentielle, on peut obtenir une reconstruction qualitative de la forme et de la réflectance d'une scène dans le cas où l'éclairage n'est pas connu. Un couple d'images est capturé : une image non flashée (image sous une illumination ambiante) et une image flashée. Une image dont l'illumination ne provient que du flash (image flash pure) peut être calculée en soustrayant l'image non flashée de l'image flashée. Nous proposons un nouvel algorithme temps réel, qui, basé sur un modèle local d'illumination de notre flash et de l'image flash pure, améliore l'information de forme fournie par le capteur de profondeur tout en retrouvant les informations de réflectance diffuse. Notre dernière contribution concerne la composition automatique d'éclairage. L'éclairage est un élément clé de la photographie. Les professionnels travaillent régulièrement avec des systèmes d'éclairage complexes afin de capturer directement des images esthétiques. Récemment, certains photographes ont tenté une nouvelle approche : plutôt que photographier une scène directement sous un éclairage complexe, ils capturent la scène sous plusieurs éclairages simples, permettant ainsi un post-traitement permettant combiner les différentes illuminations de la scène. Cette approche apporte une nouvelle dimensionnalité intéressante au post-traitement. Cependant la combinaison des images requiert des compétences en matière de photographie, et l'acquisition sous différentes conditions d'éclairage n'en est pas moins fastidieuse. Nous proposons une méthode totalement automatisée, qui, à partir d'un modèle 3D (forme et albedo) reconstruit à partir de capture d'une scène réelle, produit virtuellement les images correspondant aux différentes conditions d'éclairages. Ensuite, ces images sont combinées automatiquement, à l'aide d'un algorithme génétique, pour correspondre à un style d'éclairage fourni par l'utilisateur sous forme d'une image cible de son choix
The objective of this thesis is to take advantage of controlled illumination to enrich a video acquisition with shape and reflectance reconstructions. Today, a lot of works have tried to meet this objective. Some of them take advantage of sequential controlled illumintation to recover high quality shape and reflectance, however they either require a costly and very cumbersome fixed setup, and/or do not run in real-time. Our aim is a low cost, fast, mobile and simple acquisition setup which has to be the less intrusive possible so as to provide a greater ease of use. The first contribution of this thesis focuses on the application of the well known photometric stereo method to a video acquisition. Moreover, as a high frame rate is required by such an application, a method using sequential illumination with high frame rate cameras (electronic rolling shutter cameras) is also considered. Despite the interesting results provided by photometric stereo, we found that this latter did not provide enough qualitative results. Moreover, by its nature, photometric stereo is not really suitable for the range of applications targeted. We propose, as a second contribution, a method for recovering the shape (geometry) and the diffuse reflectance from an image (or video) using a hybrid setup consisting of a depth sensor (Kinect), a consumer camera and a partially controlled illumination (using a flash). The objective is to show how combining RGB-D acquisition with a sequential illumination is useful for shape and reflectance recovery. A pair of two images are captured : one non flashed (image under ambient illumination) and a flashed one. A pure flash image is computed by subtracting the non flashed image from the flashed image. We propose a novel and near real-time algorithm, based on a local illumination model of our flash and the pure flash image, to enhance geometry (from the noisy depth map) and recover reflectance information. Finally, our last contribution concerns an automatic method for light compositing, using rendered images. Lighting is a key element in photography. Professional photographers often work with complex lighting setups to directly capture an image close to the targeted one. Some photographers reversed this traditional workflow. Indeed, they capture the scene under several lighting conditions, then combine the captured images to get the expected one. Acquiring such a set of images is a tedious task and combining them requires some skill in photography. We propose a fully automatic method, that renders, based on a 3D reconstructed model (shape and albedo), a set of images corresponding to several lighting conditions. The resulting images are combined using a genetic optimization algorithm to match the desired lighting provided by the user as an image

This thesis describes the design and realization of a mobile robot with autonomous audio-visual control. This robot is able of movement based on sensors consisting of camera and microphone. The mechanical part consists of components made with 3D print technology and omnidirectional Mecanum wheels. Software utilizes OpenCV library for image processing and computes MFCC a DTW for voice command detection.

Ce mémoire décrit mes travaux de thèse de doctorat menés au sein de l’équipe ComSee (Computers that See) rattachée à l’axe ISPR (Image, Systèmes de Perception et Robotique) de l’Institut Pascal. Celle-ci a été financée par la Région Auvergne et le Fonds Européen de Développement Régional. Les travaux présentés s’inscrivent dans le cadre d’applications de localisation pour la robotique mobile et la Réalité Augmentée. Le framework réalisé au cours de cette thèse est une approche générique pour l’implémentation d’applications de SLAM : Simultaneous Localization And Mapping (algorithme de localisation par rapport à un modèle simultanément reconstruit). L’approche intègre une multitude de contraintes dans les processus de localisation et de reconstruction. Ces contraintes proviennent de données capteurs mais également d’a priori liés au contexte applicatif. Chaque contrainte est utilisée au sein d’un même algorithme d’optimisation afin d’améliorer l’estimation du mouvement ainsi que la précision du modèle reconstruit. Trois problèmes ont été abordés au cours de ce travail. Le premier concerne l’utilisation de contraintes sur le modèle reconstruit pour l’estimation précise d’objets 3D partiellement connus et présents dans l’environnement. La seconde problématique traite de la fusion de données multi-capteurs, donc hétérogènes et asynchrones, en utilisant un unique algorithme d’optimisation. La dernière problématique concerne la génération automatique et efficace d’algorithmes d’optimisation à contraintes multiples. L’objectif est de proposer une solution temps réel 1 aux problèmes de SLAM à contraintes multiples. Une approche générique est utilisée pour concevoir le framework afin de gérer une multitude de configurations liées aux différentes contraintes des problèmes de SLAM. Un intérêt tout particulier a été porté à la faible consommation de ressources (mémoire et CPU) tout en conservant une grande portabilité. De plus, la méta-programmation est utilisée pour générer automatiquement et spécifiquement les parties les plus complexes du code en fonction du problème à résoudre. La bibliothèque d’optimisation LMA qui a été développée au cours de cette thèse est mise à disposition de la communauté en open-source. Des expérimentations sont présentées à la fois sur des données de synthèse et des données réelles. Un comparatif exhaustif met en évidence les performances de la bibliothèque LMA face aux alternatives les plus utilisées de l’état de l’art. De plus, le framework de SLAM est utilisé sur des problèmes impliquant une difficulté et une quantité de contraintes croissantes. Les applications de robotique mobile et de Réalité Augmentée mettent en évidence des performances temps réel et un niveau de précision qui croît avec le nombre de contraintes utilisées
This report describes my thesis work conducted within the ComSee (Computers That See) team related to the ISPR axis (ImageS, Perception Systems and Robotics) of Institut Pascal. It was financed by the Auvergne Région and the European Fund of Regional Development. The thesis was motivated by localization issues related to Augmented Reality and autonomous navigation. The framework developed during this thesis is a generic approach to implement SLAM algorithms : Simultaneous Localization And Mapping. The proposed approach use multiple constraints in the localization and mapping processes. Those constraints come from sensors data and also from knowledge given by the application context. Each constraint is used into one optimization algorithm in order to improve the estimation of the motion and the accuracy of the map. Three problems have been tackled. The first deals with constraints on the map to accurately estimate the pose of 3D objects partially known in the environment. The second problem is about merging multiple heterogeneous and asynchronous data coming from different sensors using an optimization algorithm. The last problem is to write an efficient and real-time implementation of the SLAM problem using multiple constraints. A generic approach is used to design the framework and to generate different configurations, according to the constraints, of each SLAM problem. A particular interest has been put in the low computational requirement (in term of memory and CPU) while offering a high portability. Moreover, meta-programming techniques have been used to automatically and specifically generate the more complex parts of the code according to the given problem. The optimization library LMA, developed during this thesis, is made available of the community in open-source. Several experiments were done on synthesis and real data. An exhaustive benchmark shows the performances of the LMA library compared to the most used alternatives of the state of the art. Moreover, the SLAM framework is used on different problems with an increasing difficulty and amount of constraints. Augmented Reality and autonomous navigation applications show the good performances and accuracies in multiple constraints context

Le socket prothétique (dit aussi emboiture prothétique), élément d'interface essentiel entre le moignon du patient et le dispositif prothétique, est le plus souvent le lieu où se définit le degré de réussite prothétique. C'est la partie la plus critique de la prothèse, personnalisée pour s'adapter au membre résiduel unique de l'amputé. Sans une forme et un ajustement approprié du socket, la prothèse devient inconfortable, voire inutilisable, et provoque des douleurs et des problèmes de peau. La production prothétique actuelle manque encore de normes numériques universelles pour concevoir un socket. La pratique actuelle est coûteuse et repose sur les raffinements manuels du technicien orthopédiste, et la qualité de l'ajustement est strictement corrélée à ses compétences ainsi qu'aux retours subjectifs du patient lors des phases d’essai de la prothèse fabriquée. La thèse vise à mener une analyse approfondie d'une conception optimale de l'emboîture prothétique en étudiant un processus alternatif de conception assistée par ordinateur. Ce processus est entièrement basé sur le modèle virtuel du membre résiduel du patient et repose sur le calcul de l’interaction emboîture-moignon. Un calcul rapide est favorable dans ce cas, c'est pourquoi nous proposons d'utiliser le système Mass-Spring (MSS) au lieu de la méthode FE largement utilisée pour modéliser les tissus mous du membre résiduel. Une nouvelle configuration du modèle MSS est proposée pour respecter la propriété de non compressibilité des tissus mous en ajoutant des « ressorts correctifs » non linéaires. Le modèle numérique doit être généré à partir du modèle scanné du moignon. À cette fin, nous proposons un schéma de fusion de quatre capteurs de profondeur à bas coût pour un scan rapide et économique avec des techniques de réduction des erreurs. Enfin, le membre résiduel virtuel est utilisé dans la phase de conception du socket. Une méthode de conception paramétrique est proposée et étudiée. Le problème de conception est transformé en problème de satisfaction des contraintes dérivées du calcul inverse de l'interaction socket-moignon. L'approche inverse a été choisie pour éliminer le besoin d'une formulation de contact coûteuse. Ce fait conduit à des calculs rapides, et par conséquent, permet de fournir des retours numériques en temps réel pendant le processus de conception. Le système a été implémenté pas programmation C++ avec une interface graphique où les retours numériques sont donnés sous forme d’une carte de radar. La validation a été faite en comparant les résultats de notre système avec la sortie des simulations FE. Le système a été implémenté avec une interface graphique conviviale et virtuellement testé et validé numériquement. Ce système réduit les limites des pratiques actuelles. Cependant, de nombreux travaux sont encore en cours pour affiner et développer le système et le valider par des expériences cliniques
The prosthetic socket, an essential interface element between the patient's stump and prosthetic device, is most often the place where the degree of prosthetic success is defined. It is the most critical part of the prosthesis, customized to fit with the unique residual limb of the amputee. Without a proper socket shape and fit, the prosthesis becomes uncomfortable, or even unusable, and causes pain and skin issues. The state-of-the-art prosthetic production is still missing universal numerical standards to design a socket. The current practice is expensive and relies on the manual refinements of the orthopedic technician, and the fit quality strictly correlates with his skills as well as the subjective feedback of the patient. The thesis aims to conduct a deep analysis of an optimal design of the prosthetic socket by studying and developing an alternative computer-aided design process. This process is fully based on the virtual model of the patient’s residual limb and relies on the calculation of the socket-stump interaction. A fast calculation is favorable in this case, that’s why we propose to use the Mass-Spring System (MSS) instead of the widely used FE method to model the soft tissues of the residual limb. A new configuration of the MSS model is proposed to respect the non-compressibility property of the soft tissues by adding non-linear “Corrective Springs”. The numeric model is to be generated from the scanned model of the stump. For this purpose, we propose a fusion scheme of four RGB-Depth sensors for a rapid and low-cost scan with error reduction techniques. Finally, the virtual residual limb is used in the socket designing phase. A parametric design method is proposed and investigated. The design problem is transformed into a constraint-satisfaction-problem whose constraints are derived from the inverse calculation of the stump-socket interaction. The inverse approach has been chosen to eliminate the need for expensive contact formulation. This fact leads to rapid calculations, and consequently, allows to provide real-time numerical feedback during the designing process. The validation was done by comparing the results of our system with the output of FE simulations. The system has been implemented with a user-friendly graphical interface and virtually tested and numerically validated. This system reduces the limitations of the current practices. However, a lot of works is still ahead to refine and develop the system and validate it with clinical experiments

碩士
中原大學
應用數學研究所
102
There are several techniques for billiard game according to the respective trajectories of balls caused by different hitting and forces. In this article, in terms of the latest models of physics, we analyze the variations in the pool and explain every kinds of billiard techniques. In practice, we show the trajectories of billiard balls in the real time by a simulation using the Microsoft Direct 3D programming.

碩士
中原大學
應用數學研究所
102
An improved model unified for the pitch, batting, and post-impact flight phases of a baseball is established. We adapted a manner of modulation in term of 3D simulation to find bat some swing parameters that produce maximum range. The improved batted flight model incorporates experimental lift and drag profiles including the drag crisis! The improved bat-ball impact model includes the dependence of the coefficient of restitution on the approach relative velocity controlled by simulation.

Restoration of realistic animation is a critical part in the area of computer graphics. The goal of this sort of simulation is to imitate the behavior of the transformation in real life to the greatest extent. Physics-based simulation provides a solid background and proficient theories that can be applied in the simulation. In this dissertation, I will present real-time simulations which are physics-based in the area of terrain deformation and ship oscillations. When ground vehicles navigate on soft terrains such as sand, snow and mud, they often leave distinctive tracks. The realistic simulation of such vehicle-terrain interaction is important for ground based visual simulations and many video games. However, the existing research in terrain deformation has not addressed this issue effectively. In this dissertation, I present a new terrain deformation algorithm for simulating vehicle-terrain interaction in real time. The algorithm is based on the classic terramechanics theories, and calculates terrain deformation according to the vehicle load, velocity, tire size, and soil concentration. As a result, this algorithm can simulate different vehicle tracks on different types of terrains with different vehicle properties. I demonstrate my algorithm by vehicle tracks on soft terrain. In the field of ship oscillation simulation, I propose a new method for simulating ship motions in waves. Although there have been plenty of previous work on physics based fluid-solid simulation, most of these methods are not suitable for real-time applications. In particular, few methods are designed specifically for simulating ship motion in waves. My method is based on physics theories of ship motion, but with necessary simplifications to ensure real-time performance. My results show that this method is well suited to simulate sophisticated ship motions in real time applications.

碩士
國立成功大學
資訊工程學系碩博士班
96
This paper present a physics-based approach to generate 3D biped character animation that can react to dynamical environments in real-time. Our approach utilizes an inverted pendulum model to on-line adjust the desired motion trajectory from the input motion capture data. This on-line adjustment produces physically-plausible motion trajectory adapted to dynamic environments, which is then used as the desired motion for the motion controllers to follow in dynamics simulation. Rather than using the Proportional-Derivative controllers whose parameters usually cannot be easily set, our motion following control adopts a velocity-driven method which computes joint torques based on the desired joint angular velocities. Physically-correct full body motion of the 3D character is computed in dynamics simulation using the computed torques and dynamical model of the character. Our experiments demonstrate that MOCAP-following with real-time response animation can be achieved easily. Besides, physically-plausible motion style editing and automatic motion transition can also be generated naturally.

碩士
國立高雄科技大學
電機工程系
107
In this study, various terrain information such as altitude and ground image are established by “Unity 3D Terrain” and “Unity 3D visual effect engine” are used to present gorgeous real visual effect performance. Moreover, the embedded PhysX physical simulation engine technology can better reconstruct the original Terrain features. In this paper, the bending mechanism is used to obtain the ski Angle with the snow surface. The pressure sensor is used to obtain the user's pressure at various points during skiing and the user's weight to simulate the physical quantity calculated during skiing. The Bluetooth transmission package is used to control the ski movement in Unity. After establishing the terrain and interactive hardware, then objects (skis, snow, trees) can be embedded in the reconstruction of the terrain with physical behaviors such as movement, collision, acceleration and rotation can be added. Then, the acceleration/angular rate calculated by the physical model of input trajectories of skiers through TCP/IP network communication protocol connecting master-slave at both ends and the virtual images of skis. Finally, let the user feel like real skiing with motion platform reaction. Keywords: PhysX, Unity, skiing physical simulation, Stewart Platform

No
We propose a new dynamic simulation scheme for large-scale flood hazard modelling and prevention. The approach consists of a number of core parts: Digital terrain modelling with GIS data, Nona-tree space partitions (NTSP), Automatic River object recognition and registration, and a flood spreading model. The digital terrain modelling method allows the creation of a geometric real terrain model for augmented 3D environments with very large GIS data, and it can also use information gathered from aviation and satellite images with a ROAM algorithm. A spatial image segmentation scheme is described for river and flood identification and for a 3D terrain map of flooding region growth and visualisation. The region merging is then implemented by adopting Flood Region Spreading Algorithm (FRSA). Compared with the conventional methods, our approach has the advantages of being capable of realistically visualising the flooding in geometrically-real 3D environments, of handling dynamic flood behaviour in real-time and of dealing with very large-scale data modelling and visualisation.

碩士
國立臺北教育大學
玩具與遊戲設計研究所
94
Due to the fast development of hardware and graphic technologies, the transforming, lighting, and texturing in fix rendering pipeline can be replaced with programming shader used in some rendering graphic technologies and plentiful graphic effects in real-time 3D environment also can be achieved. In this study, a method which simulating the human visual system for lighting adaptation with the pupil of the eyes has been proposed. This study integrates the related graphic techniques, such as High Dynamic Range Image (HDRI)、tone reproduction and the human visual system, with the vertex shader and the pixel shader to simulate the lighting adaptation effect in the human visual system. A visual 3D rendering environment, built with vertex and pixel shader, which can produce effect with scenes changing in dark and light cases. This study simulates the dazzling light and the human visual system for light adapting with multiple-pass rendering technique. Comparing with the method proposed by Reinhard et al., this study improves the deviation in varieties of color, and separates the lighting adaptation range from the original system to achieve more real effect.

碩士
淡江大學
資訊工程學系
84
In order to make users feel immersive in an interactive visual simulation system, both of the visual render and user input must be completed in real-time. As the complexity of the virtual scene increase and the realism of the virtual environment is requested by the user, the demand of high performance computing for virtual environment is become very important. Such as supercomputers or special purpose computers are often used. But these computers are expensive. As the evolution of the computer, both PC and workstation have gaining more power with less cost. Hence, we can connect several PCs and workstations via LAN to form a distributed high-speed computing environment to meet the requirement of real-time visual simulation. Based upon this concept, several distributed real-time computing environment have proposed over this years. Such as division's dVS, MIT's VETT and SICS's DIVE ..etc. All of them allow multi-user, but confined in UNIX-based OS or special machines. In this paper, we propose a distributed run-time environment which use PCs or workstations that run WIN32-based OS and also, with the help of DIS(distributed interactive simulation) a multi-user virtual environment can be achieve. PNs theory allows a system to be modeled by a mathematical representation. Timed Petri net( TPN) is another kind of PNs. Recently, TPN is widely used to analyze the performance of distributed computing systems and it is very useful to model parallel and distributed systems. We use the properties of TPNs to model the real-time visual simulation to find the parallel , conflict tasks relation among these tasks. These tasks are then partition into a set of logic processes(LPs), which are distributed among networked distributed machines. Also, Job Dispather and Communication Interface are designed to communicate and synchronize these distributed LPs.

博士
國立臺灣大學
資訊工程學研究所
87
This dissertation addresses the problem of real-time 3D head motion tracking with a single camera. Through the analysis on a sequence of continuous facial images captured from a single video camera, the subject''s head motion in 3D space can be estimated. Two issues are discussed: feature tracking and 3D motion estimation. The purpose of feature tracking is to provide enough feature correspondence between two consecutive images, and the purpose of 3D motion estimation is to infer 3D motion from these feature correspondence. To tackle the motion-tracking problem, techniques of real-time feature tracking and 3D motion estimation are proposed. The proposed feature tracking technique is developed based on cross-correlation between two feature patterns, with additional constraints to obtain better tracking results. The proposed 3D motion estimation method includes knowledge of head motion to develop an objective function that is minimized iteratively to obtain motion parameters. Three feature points, two eye cor-ners and one nostril, are required, and the recovered motion parameters are three rota-tion angles and three translation offsets, respectively. The proposed techniques can be applied in different applications. One potential application is the model-based visual communication, where remote face images are synthesized based on parameters including those for facial expression and head mo-tion. Model-based coding is an emerging technique that can achieve very low bit-rate image coding, and is in particular applicable for mobile or network applications. A similar prototype system is developed in this dissertation. In the prototype, 3D head motion is inferred using the proposed techniques, and the recovered motion parame-ters are applied to a face synthesis module which renders a 3D texture-mapped head model in real-time. The techniques developed can not only be used in model-based visual communi-cation, but also be applied to applications requiring natural human-computer interface (HCI). A user can interact with computers or other intelligent appliances via head motions. The performance of the proposed 3D head motion tracking techniques is meas-ured on a PC with a Pentium-II 400 MHz CPU. The 3D motion estimation can update over 250 Hz, and the overall performance of the model-based visual communication system is over 25 frames/sec, with feature tracking and head model rendering in-volved.

碩士
國立交通大學
電機與控制工程系
88
The aim of this thesis is to implement a distributed visual simulation pilot training system with real-time dynamic model for aircraft and tank. we will construct virtual-reality scene(VR scene) for aircraft and tank, and develop real-time tank dynamic model. Then we integrate the VR scene, real-time dynamic module, stewart platform, and force-feedback joystick into a integrated pilot training system by distributed softeware framework and network communication. Following, we will describe VR Scene, real-time dynamic, and system integration separately. In construction of the VR scene, this thesis adopted the Coryphaeus Software, Inc. (CSI) Visual Simulation Product Suite as real-time visual simulation application development tools. Thus, we can decrease the requirement of theoretical VR background, and focus our concentration on the development of tank dynamic model and the distributed softeware framework under VR scene. In development of dynamic model, this paper first proposes a software framework of a pilot training system. Then we implement a prototype of the pilot training system by using this software framework. This thesis also proposes a dynamic simulation module for tank and multi-wheel vehicle. In order to take the effect from the suspension system of the tank into consideration, the dynamic module not only get driving commands from pilot but also acquire terrain information from the VR scene. In system integration, we use Share Memory, IPC, Socket, File Processing functionality from IRIX Operating System to develop previous proposed software framework and other communication modules in the framework. Because of the concept of communication modules, we can not only increase the expansibility of the pilot training system but also change the configuration dynamically. 1.1 研究動機 1.2 文獻回顧 1.3 虛擬實境場景簡介 1.4 實驗設備系統介紹 1.5 論文架構 第二章 Coryphaeus及場景發展介紹 2.1 OpenGL及IRIS Performer簡介 2.1.1 OpenGL簡介 2.1.2 IRIS Performer簡介 2.2 Coryphaeus簡介 2.3 DWB - 物件編修 2.4 EzT - 地形、地物編修 2.5 EzS - 場景參數設定 2.6 發展流程 第三章 飛機操控模擬訓練系統 3.1 飛機操控模擬訓練系統之架構 3.2 飛機場景製作 3.2.1 地形及地物 3.2.2 飛機物件 3.2.3 儀表顯示 3.2.4 飛機場景畫面之成果展示 3.3 飛機動態模型 第四章 戰車操控模擬訓練系統 4.1 戰車操控模擬訓練系統之架構 4.2 戰車場景之製作 4.2.1 地形、地物之編修 4.2.2 戰車車輪之編修 4.2.3 車輪、履帶之動態連結效果 4.2.4 其它特效 4.2.5 戰車場景之畫面成果展示 4.3 戰車動態模擬 4.3.1 戰車動態模擬理論推導與方法 4.3.2 戰車動態模擬模組 第五章 系統整合 5.1 虛擬實境場景底層軟體架構 5.2 場景的連線 5.3 系統流程 5.4 序列搖桿通訊介面模組 5.5 六軸運動平台「位置控制器」、「Washout控制器」通訊介面模組 5.6 力操控搖桿通訊介面模組 5.7 分散式飛機操控模擬訓練系統之整合 5.8 分散式戰車操控模擬訓練系統之整合 第六章 結論與展望 參考文獻 附錄一 飛機動態模擬方程式 附錄二 戰車動態模擬結果

碩士
國立高雄第一科技大學
電機工程研究所碩士在職專班
105
Nowadays the terrain of Google Earth just only specially efficacy with texture maps but do not have any 3D physical model and the embedded objects (buildings landmarks and so on) and also do not have any physical collision. Hence in our research based on the Unity 3D Plug-In terrain information such as elevation above sea level longitude altitude and texture maps with terrain in any location of the World. Then the PhysX physical engine and OpenGL were employed for rebuilding terrain with physical collision. Otherwise after rebuilding the terrain embedding objects (aircraft buildings) into reconstructed terrain and complete the movement collision acceleration rotation and other physical behavior. Finally the Stewart platform control system combined with washout algorithm is presented with TCP/IP Protocol Suite linking two ends, let the acceleration and angle velocity generated from virtual image be the input so that the platform motion with the virtual screen of the aircraft to achieve the same movement behavior.

Realistic and real-time computational simulation of biological organs (e.g., human kidneys, human liver) is a necessity when one tries to build a quality surgical simulator that can simulate surgical procedures involving these organs. Currently deformable models, spring-mass models, or finite element models are widely used to achieve the realistic simulations and/or the real-time performance. It is widely agreed that continuum mechanics based numerical techniques are preferred over deformable models or spring-mass models, but those techniques are computationally expensive and hence the higher accuracy offered by those numerical techniques come at the expense of speed. Hence there is a need to study the speed of different numerical techniques, while keeping an eye on the accuracy offered by those numerical techniques. Such studies are available for the Finite Element Method (FEM) but rarely available for the Boundary Element Method (BEM). Hence the present work aims to conduct a study on the viability of BEM for the real-time simulation of biological organs, and the present study is justified by the fact that BEM is considered to be inherently efficient when compared to mesh based techniques like FEM. A significant portion of literature on the real-time simulation of biological organs suggests the use of BEM to achieve better simulations. When one talks about the simulation of biological organs, one needs to have the geometry of a biological organ in hand. Geometry of biological organs of interest is not readily available many a times, and hence there is a need to extract the three dimensional (3D) geometry of biological organs from a stack of two dimensional (2D) scanned images. Software packages that can readily reconstruct 3D geometry of biological organs from 2D images are expensive. Hence, a novel procedure that requires only a few free software packages to obtain the geometry of biological organs from 2D image sequences is presented. The geometry of a pig liver is extracted from CT scan images for illustration purpose. Next, the three dimensional geometry of human kidney (left and right kidneys of male, and left and right kidneys of female) is obtained from the Visible Human Dataset (VHD). The novel procedure presented in this work can be used to obtain patient specific organ geometry from patient specific images, without requiring any of the many commercial software packages that can readily do the job. To carry out studies on the speed and accuracy of BEM, a source code for BEM is needed. Since the BEM code for 3D elasticity is not readily available, a BEM code that can solve 3D linear elastostatic problems without accounting for body forces is developed from scratch. The code comes in three varieties: a MATLAB version, a Fortran version (sequential version), and a Fortran version (parallelized version). This is the first free and open source BEM code for 3D elasticity. The developed code is used to carry out studies on the viability of BEM for the real-time simulation of biological organs, and a few representative problems involving kidneys and liver are found to give accurate solutions. The present work demonstrates that it is possible to simulate linear elastostatic behaviour in real-time using BEM without resorting to any type of precomputations, on a computer cluster by fully parallelizing the simulations and by performing simulations on different number of processors and for different block sizes. Since it is possible to get a complete solution in real-time, there is no need to separately prove that every type of cutting, suturing etc. can be simulated in real-time. Future work could involve incorporating nonlinearities into the simulations. Finally, a BEM based simulator may be built, after taking into account details like rendering.

The world population is aging, The quality life in elder people deteriorates with age, this is because of the sedentary lifestyle in which they live, consequently these countries must adapt much more rapidly to this aging. Therapy and Physical activity helps to improve health and well-being in the elders, bringing longevity and improves their life quality. The Technology has been used as a tool in various fields and there are some applications that have been developed to encourage sports through entertainment. Nintendo Wii and Kinect games had a positive impact on the overall well-being of the elderly, compared to a other group that played traditional board games. The life quality of the elderly is impaired by the lack of physical activity, entertainment and lack of memory use. This work aims to solve this problem with the implementation of a system that promotes physical activity through body movements, generate entertainment through the control of a drone in a virtual environment and promote memory through remembering movement patterns that is due perform to be able to control the virtual Drone correctly. This work makes use of wireless devices, wearable, light and with IMU sensors integrated in order to generate a body area network system that scans each arm movement and sends that information through Bluetooth Low Energy (BLE) technology to a virtual environment and control an UAV (Unamed Aereal Vehicle) remotely. The proposed system includes a 3D simulator that uses VR glasses for an immersive visualization in a virtual world, 2 Raspberry Pi devices with Sense HAT board integrated as hand controls, these plates are equipped with an IMU sensor that is responsible for the arms movement monitoring. This proposal allows an interconnection of portable devices through wireless technology and combine them with immersive virtual environments to generate a system that emulates the control of a Drone in a simulated environment. In order to adapt the system and focus on older people, it is proposed to implement 2 visualization modes and 2 difficulty modes, the visualization modes determine the perspective in which the user looks at the environment while the user controls the Drone, The First perspective, is defined by a third person camera system, where the user is layers of watching the Drone while controlling it and the second mode corresponds to a first person camera system, where the user's eyes are in the same drone position, this mode allows appreciate the environment in a better way, but does not allow to visualize the UAV. In the performed tests, each user had his / her own preferences, some of them liked to use the simulator with first persona camera configuration and others with third person camera configuration. this way the system is designed to adapt to the visualization mode of each individual. With respect to the difficulty modes, the simulator offers the possibility to use the maneuver the drone through 2 mechanisms, in easy mode, where the user only needs to make 4 movements between both hands and the difficult mode where the user requires 6 movements between both hands in order to have a total drone control, this allows the user to develop cognitive skills (Eye-hand coordination) and improve physical and mental health, when using this system. Through the tests of latency, it is determined that the transmission of data through Bluetooth Low Energy is extremely fast which means that the movements of hands that the user performs become real motions of the Virtual Drone in real time. A real time simulator is a system that offers reaction times similar to reality, this determines the efficiency of the simulator when it is used as training before using a real Drone. Performed tests with older adults reveal an evolution of skills when using the system progressively in each of the different modes of use. The interest, the entertainment and the physical activity that the system promotes in the elderly, is enough to improve their quality of life by contributing in the reduction of the sedentary, promoting the physical activity and mental state. To achieve the implementation of this system we propose a parallel development of a native Android application that makes use of the same system of body area networks of sensors to maneuver a real dron (Phantom 4) using only the movement of hands, with the object of validate the functions and movements of the virtual drone based on the movements of the real dron under the same control mechanism.