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In this thesis, we present a new approach to rendering deforming textured surfaces that takes into account variations in elasticity of the materials represented in the texture. Our approach is based on dynamically warping the parameterisation so that parameterisation distortion in a deformed pose is locally similar to the rest pose; this similarity results in apparent rigidity of the mapped texture material. The warps are also weighted, so that users have control over what appears rigid and what not. Our algorithms achieve real-time generation of warps, including their application in rendering the textured surfaces. A key factor to the achieved performance is the exploitation of the parallel nature of local optimisations by implementing the algorithms on the GPU. We demonstrate our approach with several example applications. We show warps on models using standard texture mapping as well as Ptex. We also show warps using static or dynamic/procedural texture detail, while the surface that it is mapped on deforms. A variety of use-cases is also provided: generating warps for looping animations, generating out-of-core warps of film-quality assets, approximating high-resolution warps with lower-resolution texture-space Linear Blend Skinning and dynamically preserving texture features of a model being interactively edited by an artist.

This thesis work presents a simple and practical technique for seamlessly texturing quadrilateral meshes. Using this technique, an isotropic homogeneous texture can be mapped to any quadrilateral mesh without any discontinuity or singularity in the resultant texturing. The method involves organizing a set of square texture tiles that satisfy specific boundary conditions into one texture image file which is called a tiled texture. Based on the tiled textures, we have developed an extremely simple texture mapping algorithm that randomly assigns one tile to every patch in any given quadrilateral mesh. The mapping technique developed yields singularity free textures, regardless of the singularities existing in the quadrilateral mesh, gives seamless and continuous boundaries across textures and provides an aperiodic and interesting look to the entire textured surface.

This artist??s area of research is the appropriate use of matte paintings within the context of completely computer generated films. The emphasis of research is the adaptation of analog techniques and paradigms into a digital production workspace. The purpose of this artist??s research is the development of an original method of parenting perspective projections to three-dimensional (3D) cameras, specifically tailored to result in 3D matte paintings. Research includes the demonstration of techniques combining two-dimensional (2D) paintings, 3D props and sets, as well as camera projections onto primitive geometry to achieve a convincing final composite.

Hardware texture mapping is essential for real-time rendering. Unfortunately the memory bandwidth and latency often bounds performance in current graphics architectures. Bandwidth consumption can be reduced by compressing the texture map or by using a cache. However, the way a texture map occupies memory and how it is accessed affects the pattern of memory accesses, which in turn affects cache performance. Thus texture compression schemes and cache architectures must be designed in conjunction with each other. We define a sparse texture to be a texture where a substantial percentage of the texture is constant. Sparse textures are of interest as they occur often, and they are used as parts of more general texture compression schemes. We present a hardware compatible implementation of sparse textures based on B-tree indexing and explore cache designs for it. We demonstrate that it is possible to have the bandwidth consumption and miss rate due to the texture data alone scale with the area of the region of interest. We also show that the additional bandwidth consumption and hideable latency due to the B-tree indices are low. Furthermore, the caches necessary for these textures can be quite small.

Hardware texture mapping is essential for real-time rendering. Unfortunately the memory bandwidth and latency often bounds performance in current graphics architectures. Bandwidth consumption can be reduced by compressing the texture map or by using a cache. However, the way a texture map occupies memory and how it is accessed affects the pattern of memory accesses, which in turn affects cache performance. Thus texture compression schemes and cache architectures must be designed in conjunction with each other. We define a sparse texture to be a texture where a substantial percentage of the texture is constant. Sparse textures are of interest as they occur often, and they are used as parts of more general texture compression schemes. We present a hardware compatible implementation of sparse textures based on B-tree indexing and explore cache designs for it. We demonstrate that it is possible to have the bandwidth consumption and miss rate due to the texture data alone scale with the area of the region of interest. We also show that the additional bandwidth consumption and hideable latency due to the B-tree indices are low. Furthermore, the caches necessary for these textures can be quite small.

Various biomedical technologies like CT, MRI and PET scanners provide detailed cross-sectional views of the human anatomy. The image information obtained from these scanning devices is typically represented as large data sets whose sizes vary from several hundred megabytes to about one hundred gigabytes. As these data sets cannot be stored on one's local hard drive, SDSC provides a large data repository to store such data sets. These data sets need to be accessed by researchers around the world to collaborate in their research. But the size of these data sets make them difficult to be transmitted over the current network. This thesis presents a 3-D Haar wavelet algorithm which enables these data sets to be transformed into smaller hierarchical representations. These transformed data sets are transmitted over the network and reconstructed to a 3-D volume on the client's side through progressive refinement of the images and 3-D texture mapping techniques.

Yes / We introduce a novel approach to face models, which exploits the use of Partial Differential Equations (PDE) to generate the 3D face. This addresses some common problems of existing face models. The PDE face benefits from seamless merging of surface patches by using only a relatively small number of parameters based on boundary curves. The PDE face also provides users with a great degree of freedom to individualise the 3D face by adjusting a set of facial boundary curves. Furthermore, we introduce a uv-mesh texture mapping method. By associating the texels of the texture map with the vertices of the uv mesh in the PDE face, the new texture mapping method eliminates the 3D-to-2D association routine in texture mapping. Any specific PDE face can be textured without the need for the facial expression in the texture map to match exactly that of the 3D face model.

Finally, in the tileable bidirectional texture function (BTF), we present a modular approach to apply the BTF, which is a high dimensional texture with variable lighting and viewing directions, onto object surfaces. The basic building blocks are the BTF tiles. By constructing one set of BTF tiles, a wide variety of objects can be textured seamlessly without resynthesizing the BTF. The proposed approach can nicely decouple the surface appearance from the geometry. With this appearance geometry decoupling, one can build a library of BTF tile sets to instantaneously dress and render various objects under variable lighting and viewing conditions. The core of the proposed method is the seamless synthesis of multi-dimensional BTF tiles. To tackle the enormous data, we perform synthesis in frequency domain. This not just allows the handling of large BTF data during the synthesis, but also facilitates compact storage of the BTF in GPU memory. / For texture aware halftoning, we are tackling the lost texture details in the bitonal images generated with traditional halftoning methods. We present an optimization-based halftoning technique that preserves the texture and tone similarities between the original and the halftone images. By optimizing an objective function consisting of both the texture and the tone metrics, the generated halftone images preserve human visual sensitive details as well as the local tone. It possesses the blue-noise property and does not introduce annoying pattern. Unlike existing edge-enhancement halftoning, the proposed method does not suffer from the inability of edge detector. Our method is experimented with a various kinds of images. From the multiple experiments and the user survey, our method consistently obtains the best scores among all tested methods. / In richness-preserved screening for automated manga production, we propose a framework to generate manga-style backgrounds from real photographs. It frees manga artists from tedious and time-consuming background production. Our method divides the photo-to-manga conversion into two major process, screening and line abstraction. During the screening, our goal is to preserve the visual richness in the original photograph. The key is to exploit the pattern variety in the screening space to best maintaining the original richness in reference image in terms of texture and color. To achieve this, we select screens for different regions in the image according to tone similarity, texture similarity, and chromaticity distinguishability. Multi-dimensional scaling technique is employed for the color-to-pattern mapping. For the line abstraction, we propose a simple and effective line importance model that ranks the lines based on their geometric natures. With the line importance model, users can interactively control the level of details by tunning only a few parameters. A number of results are presented to demonstrate the effectiveness and convenience of the proposed framework. / Textures appear on most of the object surfaces or scenes around our daily lives. They are something perceptual, as they only appear when certain amount of details are perceived in a suitable scale by our eyes. In computer graphics, they are essential in enriching the perceptual appearance and improving realism in rendering. Although their nature and mechanism on how human vision system perceives and interprets textures are not well understood until now, the demand for better textural quality in rendering and imaging increases continuously. Therefore, texture related researches are becoming popular topics in the graphics community in recent years. This thesis presents several novel texture aware techniques with applications for both 3D graphics and 2D imaging. They are namely texture aware halftoning, richness-preserved screening for automated manga production, and tileable bidirectional texture function (BTF). Although these applications are from different domains in computer graphics, they are sharing a common goal of improving the texture presentation in the final outcome. Major techniques involve a texture preservation technique in halftoning process, automated manga screening method with richness preservation by pattern variety, and an effective texture tile synthesis approach for high dimensional bidirectional textures. / Pang, Wai Man. / Adviser: Heng Pheng Ann. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3609. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 131-158). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Xu, Leilei. / Thesis submitted in: October 2007. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 78-84). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgement --- p.iii / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Texture and Dynamic Textures --- p.1 / Chapter 1.2 --- Related work --- p.4 / Chapter 1.3 --- Thesis Outline --- p.7 / Chapter 2 --- Image/Video Processing --- p.8 / Chapter 2.1 --- Bayesian Analysis --- p.8 / Chapter 2.2 --- Markov Property --- p.10 / Chapter 2.3 --- Graph Cut --- p.12 / Chapter 2.4 --- Belief Propagation --- p.13 / Chapter 2.5 --- Expectation-Maximization --- p.15 / Chapter 2.6 --- Principle Component Analysis --- p.15 / Chapter 3 --- Linear Dynamic System --- p.17 / Chapter 3.1 --- System Model --- p.18 / Chapter 3.2 --- Degeneracy and Canonical Model Realization --- p.19 / Chapter 3.3 --- Learning of Dynamic Textures --- p.19 / Chapter 3.4 --- Synthesizing Dynamic Textures --- p.21 / Chapter 3.5 --- Summary --- p.21 / Chapter 4 --- Dynamic Color Texture Synthesis --- p.25 / Chapter 4.1 --- Related Work --- p.25 / Chapter 4.2 --- System Model --- p.26 / Chapter 4.2.1 --- Laplacian Pyramid-based DCTS Model --- p.28 / Chapter 4.2.2 --- RBF-based DCTS Model --- p.28 / Chapter 4.3 --- Experimental Results --- p.32 / Chapter 4.4 --- Summary --- p.42 / Chapter 5 --- Dynamic Textures using Multi-resolution Analysis --- p.43 / Chapter 5.1 --- System Model --- p.44 / Chapter 5.2 --- Multi-resolution Descriptors --- p.46 / Chapter 5.2.1 --- Laplacian Pyramids --- p.47 / Chapter 5.2.2 --- Haar Wavelets --- p.48 / Chapter 5.2.3 --- Steerable Pyramid --- p.49 / Chapter 5.3 --- Experimental Results --- p.51 / Chapter 5.4 --- Summary --- p.55 / Chapter 6 --- Motion Transfer --- p.59 / Chapter 6.1 --- Problem formulation --- p.60 / Chapter 6.1.1 --- Similarity on Appearance --- p.61 / Chapter 6.1.2 --- Similarity on Dynamic Behavior --- p.62 / Chapter 6.1.3 --- The Objective Function --- p.65 / Chapter 6.2 --- Further Work --- p.66 / Chapter 7 --- Conclusions --- p.67 / Chapter A --- List of Publications --- p.68 / Chapter B --- Degeneracy in LDS Model --- p.70 / Chapter B.l --- Equivalence Class --- p.70 / Chapter B.2 --- The Choice of the Matrix Q --- p.70 / Chapter B.3 --- Swapping the Column of C and A --- p.71 / Chapter C --- Probability Density Functions --- p.74 / Chapter C.1 --- Probability Distribution --- p.74 / Chapter C.2 --- Joint Probability Distributions --- p.75 / Bibliography --- p.78