No description available.

The development of a satisfactory the three-dimensional image system is a constant pursuit of the scientific community and entertainment industry. Among the many different methods of producing three-dimensional images, integral imaging is a technique that is capable of creating and encoding a true volume spatial optical model of the object scene in the form of a planar intensity distribution by using unique optical components. The generation of depth maps from three-dimensional integral images is of major importance for modern electronic display systems to enable content-based interactive manipulation and content-based image coding. The aim of this work is to address the particular issue of analyzing integral images in order to extract depth information from the planar recorded integral image. To develop a way of extracting depth information from the integral image, the unique characteristics of the three-dimensional integral image data have been analyzed and the high correlation existing between the pixels at one microlens pitch distance interval has been discovered. A new method of extracting depth information from viewpoint image extraction is developed. The viewpoint image is formed by sampling pixels at the same local position under different micro-lenses. Each viewpoint image is a two-dimensional parallel projection of the three-dimensional scene. Through geometrically analyzing the integral recording process, a depth equation is derived which describes the mathematic relationship between object depth and the corresponding viewpoint images displacement. With the depth equation, depth estimation is then converted to the task of disparity analysis. A correlation-based block matching approach is chosen to find the disparity among viewpoint images. To improve the performance of the depth estimation from the extracted viewpoint images, a modified multi-baseline algorithm is developed, followed by a neighborhood constraint and relaxation technique to improve the disparity analysis. To deal with the homogenous region and object border where the correct depth estimation is almost impossible from disparity analysis, two techniques, viz. Feature Block Pre-selection and “Consistency Post-screening, are further used. The final depth maps generated from the available integral image data have achieved very good visual effects.

No description available.

Three 3D nonlinear finite-element (FE) models are developed to study the behavior of concrete beams and plates with and without externally reinforcement of fibre reinforced polymer (FRP). Ramtekkar’s mixed layer-wise 3 dimensional (3D) 18-node FE model (108 degrees-of-freedom, DOFs) is modified to accommodate the nonlinear concrete and elasto-plastic steel behaviour. Saenz’s stress-strain equation is used for material nonlinearity of concrete. As in any 3D mixed FE analysis, the run time using the model can be computationally expensive. Two additional layer-wise 18-node FE models: Displacement FE model (54 DOF) and transitional FE model (81 DOF) are developed. The displacement FE model is based on purely displacement field, i.e. only displacement components are enforced throughout the thickness of the structures. The transitional FE model has six DOF (three displacement components in the coordinate axis direction and three transverse stress components - where z is the thickness direction) per node in the upper surface and only three DOF (three displacement components in the coordinate axis direction) per node in the bottom surface.The analysis of reinforced concrete (RC) beam strengthened with FRP and composite plate using these models are verified against the experimental results and the results from the commercial software, ANSYS respectively. Several parametric studies are done on composite RC beam and composite plate.

Stuttgart, Univ., Studienarb., 2002.

<p>SammanfattningDen här rapporten beskriver arbetet att ta fram försöksmaterial i form av 3D-modeller med tillhörande animationer till det Internetbaserade rådgivningsverktyget för läkemedelsprodukter AssistansPlus*. Utöver detta ger rapporten en inblick i hur framtagning av 3D-medierat material för Internet, inom området rådgivning och presentation, kan se ut generellt.Viktigt att tänka på vid arbetet med modeller och animationer till AssistansPlus är att de måste anpassas till W3D formatet, som 3D spelaren i verktyget är utvecklad i. De viktigaste var här att veta vad som följde med vid en export till formatet W3D (animerandet måste ske på ett relativt analogt sett, vissa bildformat för texturerna fungerar bättre än andra etc.). Rapporten innehåller en checklista som ska fungera som en guide vid framtida framtagning av material till verktyget. Filstorlek är av stor vikt i arbete med 3D för Internet och var därför en viktig del också i uppdraget.</p><p>Att begränsa filernas storlek genom att använda så få ytor som möjligt, genom att stilisera</p><p>modellerna och genom att göra texturer så bra som möjligt i förhållande till filstorleken, var viktiga delar arbetet. För och nackdelar med denna rika mediatyp diskuteras i rapporten. Aspekter som tas upp är navigering</p><p>och interaktivitet samt synen på 3D som medietyp. Många Internetanvändare har aldrig interagerat med 3D, varför en väl genomtänkt navigering är viktig. 3D kopplas gärna ihop med spel och animerad film. Att behandle 3D som en mediatyp bland de på Internet mer etablerade (som text bild och film) är viktigt. Det finns relativt många format och visningsverktyg att välja mellan i arbete med 3D på Internet. Det finns inget enskilt format som idag kan anses vara att rekomendera. En framtida Flash-version</p><p>med implementerat stöd för 3D hantering tycks vara den mest sannolika allmäna standarden i framtiden.3D-material för användning i webbläsare är rapportens fokus och innehållet begränsas därför till detta. Vidare begränsas innehållet till webbaserat 3D med syfte att informera, instruera eller marknadsföra kring en produkt. 3D-applikationer inom området nöje behandlas inte. Trots att utvecklingen av 3D-grafik i hög grad har drivits framåt av spel- och filmindustrin, är detta områden</p><p>som det inte läggs fokus på. Dock är det så att områdena ofta går in i varandra; paralleller är därför förekommande.</p>

No description available.

As áreas de visualização e modelagem baseados em pontos têm sido pesquisadas ativamente na computação gráfica. Pontos com atributos (por exemplo, normais) são geralmente chamados de surfels e existem vários algoritmos para a manipulação e visualização eficiente deles. Um ponto chave para a eficiência de muitos métodos é o uso de estruturas de particionamento do espaço. Geralmente octrees e KD-trees, por utilizarem cortes alinhados com os eixos são preferidas em vez das BSP-trees, mais genéricas. Neste trabalho, apresenta-se uma estrutura chamada Constrained BSP-tree (CBSP-tree), que pode ser vista como uma estrutura intermediárias entre KD-trees e BSP-trees. A CBSP-tree se caracteriza por permitir cortes arbitrários desde que seja satisfeito um critério de validade dos cortes. Esse critério pode ser redefinido de acordo com a aplicação. Isso permite uma aproximação melhor de regões curvas. Apresentam-se algoritmos para construir CBSP-trees, valendo-se da flexibilidade que a estrutura oferece, e para realizar operações booleanas usando uma nova classificação de interior/exterior.

A partir das dimensões dos indivíduos pode-se definir dimensionamentos adequados para os produtos e postos de trabalho, proporcionando segurança e conforto aos usuários. Com o avanço da tecnologia de digitalização de imagens (escaneamento) 3D, é possível tirar algumas medidas de maneira mais rápida e com a redução da presença do entrevistado durante o processo. No entanto, faltam estudos que avaliem estas tecnologias no Brasil, sendo necessária a realização de uma comparação das tecnologias e das respectivas precisões para que seu uso em pesquisas. Com o objetivo de oferecer métodos comparativos para escolha dos marcadores e equipamentos a serem utilizados em uma pesquisa antropométrica tridimensional da população brasileira, no presente estudo estão comparadas duas tecnologias de escaneamento: o sistema a laser WBX da empresa norte americana Cyberware e o sistema MHT da empresa russa Artec Group. O método para avaliação da precisão dimensional dos dados advindos desses equipamentos de digitalização de imagens 3D teve cinco etapas: Estudo dos processos de escaneamento; Escaneamento dos marcadores de pontos anatômicos; Escaneamento utilizando um corpo de prova cilíndrico; Escaneamento de um manequim; Escaneamento de um voluntário que teve seus pontos anatômicos marcados para a retirada de medidas. Foi feita uma comparação entre as medidas retiradas manualmente, por meio de antropômetro e virtualmente, com o auxílio do software de modelagem tridimensional Rhinoceros. Em relação aos resultados obtidos na avaliação do manequim e do voluntário, concluiu-se que a magnitude do erro absoluto é semelhante para ambos os scanners, e permanece constante independentemente das dimensões sob análise. As principais diferenças são em relação às funcionalidades dos equipamentos. / Only from the dimensions of individuals it is possible to define appropriate sizing for products and workplaces, providing security and comfort to users. With the evolution of 3D digital imaging technology (3D scanning), it is possible to take some measurements faster and reduce the need of the interviewee during the process. However, there are few studies that evaluate these technologies in Brazil. It is necessary to compare these equipments in order to know their precision so they can be used in researches. In order to choose anatomical markers and equipments, this study compares two different equipments: Cyberware WBX laser scanner and Artec Group MHT white light scanner. The method for assessing the dimensional accuracy of the data obtained from those scanning 3D imaging equipment had five steps: Study of the scanning processes; Scanning using a cylindrical object; Scanning a mannequin; Scanning a volunteer who had his anatomical points marked for taking measurements. The comparison was made between the measurements taken manually with an anthropometer and virtually using the 3D modeling software Rhinoceros. Based on results obtained in the evaluation of the mannequin and volunteer, it was concluded that the absolute error is similar for both scanners and remains constant regardless of the size under consideration. The main differences are the features of each equipment.

La reconnaissance des expressions faciales est une tâche difficile, qui a reçu un intérêt croissant au sein de la communauté des chercheurs, et qui impacte les applications dans des domaines liés à l'interaction homme-machine (IHM). Dans le but de construire des systèmes IHM approchant le comportement humain et émotionnellement intelligents, les scientifiques essaient d'introduire la composante émotionnelle dans ce type de systèmes. Le développement récent des capteurs d'acquisition 3D a fait que les données 3D deviennent de plus en plus disponibles, et ce type de données vient pour remédier à des problèmes inhérents aux données 2D tels que les variations d'éclairage, de pose et d'échelle et de faible résolution. Plusieurs bases de données 3D du visage sont publiquement disponibles pour les chercheurs dans le domaine de la reconnaissance d'expression faciale leur permettant ainsi de valider et d'évaluer leurs approches. Cette thèse traite le problème la reconnaissance d'expression faciale et propose une approche basée sur l'analyse de forme pour la reconnaissance d'expression dans un cadre statique (relatif à une seule image) et dynamique (relatif à une séquence vidéo). Tout d'abord, une représentation du modèle 3D du visage basée sur les courbes est proposée pour décrire les traits du visage. Puis, une fois ces courbes sont extraites, l'information de forme qui leur est liée est quantifiée en utilisant un cadre de travail basé sur la géométrie Riemannienne. Nous obtenons, par la suite, des scores de similarité entre les différentes formes locales du visage. Nous constituons, alors, un vecteur de caractéristiques associées à chaque surface faciale. Ensuite, ces caractéristiques sont utilisées comme paramètres d'entrée à des algorithmes d'apprentissage automatique et de classification pour la reconnaissance d'expressions. Des expérimentations exhaustives sont alors entreprises pour valider notre approche et des résultats sont présentés et comparés aux résultats des travaux de l'état de l'art. / Facial expression recognition is a challenging task, which has received growing interest within the research community, impacting important applications in fields related to human machine interaction (HMI). Toward building human-like emotionally intelligent HMI devices, scientists are trying to include the essence of human emotional state in such systems. The recent development of 3D acquisition sensors has made 3D data more available, and this kind of data comes to alleviate the problems inherent in 2D data such as illumination, pose and scale variations as well as low resolution. Several 3D facial databases are publicly available for the researchers in the field of face and facial expression recognition to validate and evaluate their approaches. This thesis deals with facial expression recognition (FER) problem and proposes an approach based on shape analysis to handle both static and dynamic FER tasks. Our approach includes the following steps: first, a curve-based representation of the 3D face model is proposed to describe facial features. Then, once these curves are extracted, their shape information is quantified using a Riemannain framework. We end up with similarity scores between different facial local shapes constituting feature vectors associated with each facial surface. Afterwards, these features are used as entry parameters to some machine learning and classification algorithms to recognize expressions. Exhaustive experiments are derived to validate our approach and results are presented and compared to the related work achievements.