Fast Random Access to Wavelet Compressed Volumetric Data Using Hashing

We present a new approach to lossy storage of the coefficients of wavelet transformed data. While it is common to store the coefficients of largest magnitude (and let all other coefficients be zero), we allow a slightly different set of coefficients to be stored. This brings into play a recently proposed hashing technique that allows space efficient storage and very efficient retrieval of coefficients. Our approach is applied to compression of volumetric data sets. For the ``Visible Man'' volume we obtain up to 80% improvement in compression ratio over previously suggested schemes. Further, the time for accessing a random voxel is quite competitive

A framework for digital sunken relief generation based on 3D geometric models

Sunken relief is a special art form of sculpture whereby the depicted shapes are sunk into a given surface. This is traditionally created by laboriously carving materials such as stone. Sunken reliefs often utilize the engraved lines or strokes to strengthen the impressions of a 3D presence and to highlight the features which otherwise are unrevealed. In other types of reliefs, smooth surfaces and their shadows convey such information in a coherent manner. Existing methods for relief generation are focused on forming a smooth surface with a shallow depth which provides the presence of 3D figures. Such methods unfortunately do not help the art form of sunken reliefs as they omit the presence of feature lines. We propose a framework to produce sunken reliefs from a known 3D geometry, which transforms the 3D objects into three layers of input to incorporate the contour lines seamlessly with the smooth surfaces. The three input layers take the advantages of the geometric information and the visual cues to assist the relief generation. This framework alters existing techniques in line drawings and relief generation, and then combines them organically for this particular purpose

Efficient Point-Cloud Processing with Primitive Shapes

This thesis presents methods for efficient processing of point-clouds based on primitive shapes. The set of considered simple parametric shapes consists of planes, spheres, cylinders, cones and tori. The algorithms developed in this work are targeted at scenarios in which the occurring surfaces can be well represented by this set of shape primitives which is the case in many man-made environments such as e.g. industrial compounds, cities or building interiors. A primitive subsumes a set of corresponding points in the point-cloud and serves as a proxy for them. Therefore primitives are well suited to directly address the unavoidable oversampling of large point-clouds and lay the foundation for efficient point-cloud processing algorithms. The first contribution of this thesis is a novel shape primitive detection method that is efficient even on very large and noisy point-clouds. Several applications for the detected primitives are subsequently explored, resulting in a set of novel algorithms for primitive-based point-cloud processing in the areas of compression, recognition and completion. Each of these application directly exploits and benefits from one or more of the detected primitives' properties such as approximation, abstraction, segmentation and continuability

Two algorithms for Lossy compression of 3D images

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.Includes bibliographical references (leaves 107-108).by Bernard Yiow-Min Chin.M.Eng

Dynamic texture synthesis in image and video processing.

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

Methods for Real-time Visualization and Interaction with Landforms

This thesis presents methods to enrich data modeling and analysis in the geoscience domain with a particular focus on geomorphological applications. First, a short overview of the relevant characteristics of the used remote sensing data and basics of its processing and visualization are provided. Then, two new methods for the visualization of vector-based maps on digital elevation models (DEMs) are presented. The first method uses a texture-based approach that generates a texture from the input maps at runtime taking into account the current viewpoint. In contrast to that, the second method utilizes the stencil buffer to create a mask in image space that is then used to render the map on top of the DEM. A particular challenge in this context is posed by the view-dependent level-of-detail representation of the terrain geometry. After suitable visualization methods for vector-based maps have been investigated, two landform mapping tools for the interactive generation of such maps are presented. The user can carry out the mapping directly on the textured digital elevation model and thus benefit from the 3D visualization of the relief. Additionally, semi-automatic image segmentation techniques are applied in order to reduce the amount of user interaction required and thus make the mapping process more efficient and convenient. The challenge in the adaption of the methods lies in the transfer of the algorithms to the quadtree representation of the data and in the application of out-of-core and hierarchical methods to ensure interactive performance. Although high-resolution remote sensing data are often available today, their effective resolution at steep slopes is rather low due to the oblique acquisition angle. For this reason, remote sensing data are suitable to only a limited extent for visualization as well as landform mapping purposes. To provide an easy way to supply additional imagery, an algorithm for registering uncalibrated photos to a textured digital elevation model is presented. A particular challenge in registering the images is posed by large variations in the photos concerning resolution, lighting conditions, seasonal changes, etc. The registered photos can be used to increase the visual quality of the textured DEM, in particular at steep slopes. To this end, a method is presented that combines several georegistered photos to textures for the DEM. The difficulty in this compositing process is to create a consistent appearance and avoid visible seams between the photos. In addition to that, the photos also provide valuable means to improve landform mapping. To this end, an extension of the landform mapping methods is presented that allows the utilization of the registered photos during mapping. This way, a detailed and exact mapping becomes feasible even at steep slopes

3D digital relief generation.

This thesis investigates a framework for generating reliefs. Relief is a special kind of sculptured artwork consisting of shapes carved on a surface so as to stand out from the surrounding background. Traditional relief creation is done by hand and is therefore a laborious process. In addition, hand-made reliefs are hard to modify. Contrasted with this, digital relief can offer more flexibility as well as a less laborious alternative and can be easily adjusted. This thesis reviews existing work and offers a framework to tackle the problem of generating three types of reliefs: bas reliefs, high reliefs and sunken reliefs. Considerably enhanced by incorporating gradient operations, an efficient bas relief generation method has been proposed, based on 2D images. An improvement of bas relief and high relief generation method based on 3D models has been provided as well, that employs mesh representation to process the model. This thesis is innovative in describing and evaluating sunken relief generation techniques. Two types of sunken reliefs have been generated: one is created with pure engraved lines, and the other is generated with smooth height transition between lines. The latter one is more complex to implement, and includes three elements: a line drawing image provides a input for contour lines; a rendered Lambertian image shares the same light direction of the relief and sets the visual cues and a depth image conveys the height information. These three elements have been combined to generate final sunken reliefs. It is the first time in computer graphics that a method for digital sunken relief generation has been proposed. The main contribution of this thesis is to have proposed a systematic framework to generate all three types of reliefs. Results of this work can potentially provide references for craftsman, and this work could be beneficial for relief creation in the fields of both entertainment and manufacturing