Browsing by Subject "Three-dimensional display system."

Now showing 1 - 9 of 9

Open Access
3D hair design and key frame animation in real time
(2008) Başarankut, Barkın
Computer generated animations of humans, animals and all other kinds of objects have been studied extensively during the last two decades. The key for creating good animations has been to correctly imitate the behaviors of real objects and reflect these into computer generated images. With the rapid development of computer technology, creating realistic simulations has become possible, and the most striking components of these realistic animations happen to be the most dynamic (moving) parts; hair, in the case of human animations. With the development of high quality hair animations, the concern is not only creating physically correct animations, but also controlling these animations. An implementation of a key frame hair animation creation system, supported by a hair design tool, helping to model and animate hair easily, and provide these functionalities in real time is the aim of the proposed system. This work reviews several hair animation and sketching techniques, and proposes a system that provides a complete level of control (capable of controlling even the individual hair strands) of key frame animation and hair design in real time.
Open Access
3D hair sketching for real-time hair modeling and dynamic simulations
(2008) Aras, Rıfat
Hair has been an active research area in computer graphics society for over a decade. Different approaches have been proposed for different aspects of hair research such as modeling, simulating, animating and rendering. In this thesis, we introduce a sketch-based tool making use of direct manipulation interfaces to create hair models and furthermore simulate the created hair models under physically based constraints in real-time. Throughout the thesis, the created tool will be analyzed with respect to different aspects of the problem such as hair modeling, hair simulation, hair sketching and hair rendering.
Open Access
Cubist style rendering of 3D virtual environments
(2012) Arpa, Sami
Cubism, pioneered by Pablo Picasso and Georges Braque, was a breakthrough in art, influencing artists to abandon existing traditions. In this thesis, we present a novel approach for cubist rendering of 3D synthetic environments. Rather than merely imitating cubist paintings, we apply the main principles of Analytical Cubism to 3D graphics rendering. In this respect, we develop a new cubist camera providing an extended view, and a perceptually based spatial imprecision technique that keeps the important regions of the scene within a certain area of the output. Additionally, several methods to provide a painterly style are applied. We demonstrate the effectiveness of our extending view method by comparing the visible face counts in the images rendered by the cubist camera model and the traditional perspective camera. Besides, we give an overall discussion of final results and apply user tests in which users compare our results very well with Analytical Cubist paintings but not Synthetic Cubist paintings.
Open Access
A dept perception aware pen-based 3D sketching system
(2012) Yıldız, Cansın
This thesis proposes a method that resembles a natural pen and paper interface to create curve based 3D sketches. The system is particularly useful for representing initial 3D design ideas without much effort. Users interact with the system by the help of a pressure sensitive pen tablet, and a camera. The input strokes of the users are projected onto a drawing plane, which serves as a paper that they can place anywhere in the 3D scene. The resulting 3D sketch is visualized emphasizing depth perception by implementing several monocular depth cues, including motion parallax performed by tracking user’s head position. Our evaluation involving several naive users suggest that the system is suitable for a broad range of users to easily express their ideas in 3D. We further analyze the system with the help of an architect to demonstrate the expressive capabilities of the system that a professional can benefit.
Open Access
MARS: a tool-based modeling, animation and parallel rendering system
(1992) Aktıhanoğlu, Murat
A b stract: This thesis describes a system for modeling, animating, previewing and rendering articulated objects. Tl^^ system has a modeler which models objects, consisting of joints and segments. The animatoi- interactively positions the articulated object in its stick, control vertex or rectangular prism representation into the keyframes, interpolates inbetweens and previews the motion in real time. Then the data representing the motion and the models is sent to a multicomputer {iPSC/2 Ilypercube^). The frames are rendered in parallel by distributed processing techniques, exploiting the coherence between successive frames, thus cutting down the rendering time significantly. The main aim of this research has been to make a detailed study on rendering of a sequence of 3D scenes. The results show that due to an inherent correlation between the 3D scenes, a much more efficient rendering than the conventional sequential one can be done.
Open Access
Modeling 3D objects with free-form surfaces using 2D sketches
(2011) Akatürk, Emre
Using sketches for 3D modelling is a popular research area, which is expected since using 2D sketches feels natural to most of the artists. Many techniques have been proposed to enable an intuitive and competent tool for 3D object creation. In the light of the previous research in this area, we designed a system that enables creation of 3D free-form objects with details. Our system aims to enable users to easily create simple free-form objects using strokes and perturb their surfaces using sketches that provide contours of details and shading information. We provide the user with the ability to create a 3D simple object just by drawing its silhouette. We take this stroke input and create a simple 3D object. Then we allow the user to shade the parts of the 2D silhouette drawn before. We take the shading information and use shape from shading techniques to create a height map and apply the height map on the surface of the object to construct a perturbed surface for the previously created mesh. With our system, it is possible to create and modify 3D meshes easily and intuitively.
Open Access
Perceived quality assessment in object-space for animated 3D models
(2012) Yakut, Işıl Doğa
Computational models and methods to handle 3D graphics objects continue to emerge with the wide-range use of 3D models and rapid development of computer graphics technology. Many 3D model modification methods exist to improve computation and transfer time of 3D models in real-time computer graphics applications. Providing user with the least visually-deformed model is essential for 3D modification tasks. In this thesis, we propose a method to estimate the visually perceived differences on animated 3D models. The model makes use of Human Visual System models to mimic visual perception. It can also be used to generate a 3D sensitivity map for a model to act as a guide during the application of modifications. Our approach gives a perceived quality measure using 3D geometric representation by incorporating two factors of Human Visual System (HVS) that contribute to perception of differences. First, spatial processing of human vision model enables us to predict deformations on the surface. Secondly, temporal effects of animation velocity are predicted. Psychophysical experiment data is used for both of these HVS models. We used subjective experiments to verify the validity of our proposed method.
Open Access
Representation, editing and real-time visualization of complex 3D terrains
(2012) Koca, Çetin
Terrain rendering is a crucial part of many real-time computer graphics applications such as video games and visual simulations. It provides the main frame-ofreference for the observer and constitutes the basis of an imaginary or simulated world that encases the observer. Storing and rendering terrain models in real-time applications usually require a specialized approach due to the sheer magnitude of data available and the level of detail demanded. The easiest way to process and visualize such large amounts of data in real-time is to constrain the terrain model in several ways. This process of regularization decreases the amount of data to be processed and also the amount of processing power needed at the cost of expressivity and the ability to create interesting terrains. The most popular terrain representation, by far, used by modern real-time graphics applications is a regular 2D grid where the vertices are displaced in a third dimension by a displacement map, conventionally called a height map. It is the simplest and fastest possible terrain representation, but it is not possible to represent complex terrain models that include interesting terrain features such as caves, overhangs, cliffs and arches using a simple 2D grid and a height map. We propose a novel terrain representation combining the voxel and height map approaches that is expressive enough to allow creating complex terrains with caves, overhangs, cliffs and arches, and efficient enough to allow terrain editing, deformations and rendering in real-time. We also explore how to apply lighting, texturing, shadowing and level-of-detail to the proposed terrain representation.
Open Access
Visual attention models and applications to 3D computer graphics
(2012) Bülbül, Muhammed Abdullah
3D computer graphics, with the increasing technological and computational opportunities, have advanced to very high levels that it is possible to generate very realistic computer-generated scenes in real-time for games and other interactive environments. However, we cannot claim that computer graphics research has reached to its limits. Rendering photo-realistic scenes still cannot be achieved in real-time; and improving visual quality and decreasing computational costs are still research areas of great interest. Recent e orts in computer graphics have been directed towards exploiting principles of human visual perception to increase visual quality of rendering. This is natural since in computer graphics, the main source of evaluation is the judgment of people, which is based on their perception. In this thesis, our aim is to extend the use of perceptual principles in computer graphics. Our contribution is two-fold: First, we present several models to determine the visually important, salient, regions in a 3D scene. Secondly, we contribute to use of de nition of saliency metrics in computer graphics. Human visual attention is composed of two components, the rst component is the stimuli-oriented, bottom-up, visual attention; and the second component is task-oriented, top-down visual attention. The main di erence between these components is the role of the user. In the top-down component, viewer's intention and task a ect perception of the visual scene as opposed to the bottom-up component. We mostly investigate the bottom-up component where saliency resides. We de ne saliency computation metrics for two types of graphical contents. Our rst metric is applicable to 3D mesh models that are possibly animating, and it extracts saliency values for each vertex of the mesh models. The second metric we propose is applicable to animating objects and nds visually important objects due to their motion behaviours. In a third model, we present how to adapt the second metric for the animated 3D meshes. Along with the metrics of saliency, we also present possible application areas and a perceptual method to accelerate stereoscopic rendering, which is based on binocular vision principles and makes use of saliency information in a stereoscopic rendering scene. Each of the proposed models are evaluated with formal experiments. The proposed saliency metrics are evaluated via eye-tracker based experiments and the computationally salient regions are found to attract more attention in practice too. For the stereoscopic optimization part, we have performed a detailed experiment and veri ed our model of optimization. In conclusion, this thesis extends the use of human visual system principles in 3D computer graphics, especially in terms of saliency.