We present a new algorithm to create fair discrete surfaces satisfying prescribed G/sup 1/ boundary constraints. All surfaces are built by discretizing a partial differential equation based on pure geometric intrinsic...
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We present a new algorithm to create fair discrete surfaces satisfying prescribed G/sup 1/ boundary constraints. All surfaces are built by discretizing a partial differential equation based on pure geometric intrinsics. The construction scheme is designed to produce meshes that are partitioned into regular domains. Using this knowledge in advance we can develop a fast iterative algorithm resulting in surfaces of high aesthetic quality that have no local mean curvature extrema in the interior.
The demand on virtual planning systems is increasing, in particular for technical pretentious surgical interventions such as intracranial endoscopy. In this paper, a new virtual system for neuroendoscopy is presented....
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The demand on virtual planning systems is increasing, in particular for technical pretentious surgical interventions such as intracranial endoscopy. In this paper, a new virtual system for neuroendoscopy is presented. The main purpose of this system is to provide support for the planning and training of neuroendoscopic interventions. The software is applied for virtual endoscopic visualization of three-dimensional magnetic resonance data sets, using a clinical magnetic resonance scanner. Rendering is performed on a Hewlett-Packard unix workstation. Virtual endoscopy provides a three-dimensional view of the cerebral ventricles with good visualization of anatomic details. The rendering system used allows the generation of fly-through sequences through the entire ventricular system in real-time. Navigation is controlled by mouse movements. The visualization of the computer generated intraventricular spaces is adapted to the characteristics of the optical endoscope. The presented virtual neuroendoscopy system is a promising tool for planning and training of neuroendoscopic procedures. It provides the ability to simulate these procedures based on the patient's individual anatomy, prior to surgery.
Gives an overview of some recent methods useful for local and global shape analysis and for the design of solids. These methods include, as new tools for global and local shape analysis, the spectra of the Laplace and...
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Gives an overview of some recent methods useful for local and global shape analysis and for the design of solids. These methods include, as new tools for global and local shape analysis, the spectra of the Laplace and Laplace-Beltrami operators and the concept of stable umbilical points, i.e. stable singularities of the "principal curvature line" wire-frame model of the solid's boundary surface. Most of the material in this paper deals with the medial axis transform as a tool for shape interrogation, reconstruction, modification and design. We show that it appears to be possible to construct an intuitive user interface that allows one to mould shapes by employing the medial axis transform. We also explain that the medial axis and Voronoi diagram can also be defined and computed on free surfaces in a setting where the geodesic distance between two points p and q on a surface S is defined by the shortest surface path on S joining the two points p, q. This leads to the natural and computable generalized concepts of the geodesic medial axis and geodesic Voronoi diagram on free-form surfaces. Both can be computed with a reasonable speed and with high accuracy (of about 12 digits when double floating-point arithmetic is used for the computations).
Distributed object systems are known to be very complex. Consequently it is very difficult, if not impossible, to see the overall relationship among participating objects in the system. That complicates the issues con...
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Distributed object systems are known to be very complex. Consequently it is very difficult, if not impossible, to see the overall relationship among participating objects in the system. That complicates the issues connected with performance tuning and maintenance. An economical way to visualize the system is clearly needed. In this paper, we propose a tracing facility for Java-based distributed object system, especially Java RMI (Remote Method Invocation). Our visualization system VisOK (Visual Object-Kit) uses two-phase hybrid post-mortem/on-the-fly technique. The fundamental tracing part has a flexible and dynamic mechanism. The main idea behind the tracing technique is the plug-in sensor model (PSM). There is a close relationship between tracing part and the visualization part. For effective visualization of a working system, the causality of events has to be preserved VisOK supports global event ordering. And for collecting and assembling local states of objects, we propose a distributed snapshot algorithm.
A key issue in performing stereo reconstruction is to find stereo correspondences. For this purpose a novel unified framework for arbitrary area based correlation methods is presented. The commonly neglected problem o...
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Let A and B be two convex polytopes in R3 with m and n facets, respectively. The penetration depth of A and B, denoted as π(A, B), is the minimum distance by which A has to be translated so that A and B do not inters...
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An ideal triangle mesh compression technology would simultaneously support the following objectives: (1) progressive refinements of the received mesh during decompression, (2) nearly optimal compression ratios for bot...
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An ideal triangle mesh compression technology would simultaneously support the following objectives: (1) progressive refinements of the received mesh during decompression, (2) nearly optimal compression ratios for both geometry and connectivity, and (3) in-line, real-time decompression algorithms for hardware or software implementations. Because these three objectives impose contradictory constraints, previously reported efforts have focused primarily on one (sometimes two) of these objectives. The SQUEEZE technique introduced in this paper addresses all three constraints simultaneously, and attempts to provide the best possible compromise. For a mesh of T triangles, SQUEEZE compresses the connectivity to 3.7T bits, which is competitive with the best progressive compression techniques reported so far. The geometric prediction error encoding technique introduced in this paper leads to a geometry compression that is improved by 20% over that of previous schemes. Our initial implementation on a 300-MHz CPU achieved a decompression rate of up to 46,000 triangles per second. SQUEEZE downloads a model through a number of successive refinement stages, providing the benefit of progressivity.
In recent years there has been an increased interest in metal foams in the field of material science. The stress absorbing potential is one of the most interesting properties for the application of aluminium foam (e.g...
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A key issue in performing stereo reconstruction is to find stereo correspondences. For this purpose a novel unified framework for arbitrary area based correlation methods is presented. The commonly neglected problem o...
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ISBN:
(纸本)0769507506
A key issue in performing stereo reconstruction is to find stereo correspondences. For this purpose a novel unified framework for arbitrary area based correlation methods is presented. The commonly neglected problem of ambiguities is addressed and a solution based on relaxation of match candidates is introduced. The method comes with the major benefits of a reverse matching step at almost no extra computational cost. The results of one match direction is used to select match candidates. Then these candidates are correlated backward with a different method. The proposed framework does not require any initial estimations. Experiments are performed on ground truth under varying geometric and varying noise conditions. Finally, the method is compared to a number of well known techniques.
Realistic animation of soft objects such as cloth is essential for plausible character animation. Many techniques have been proposed for the simulation of soft objects, and most of them are based on numerical integrat...
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Realistic animation of soft objects such as cloth is essential for plausible character animation. Many techniques have been proposed for the simulation of soft objects, and most of them are based on numerical integration. Among the techniques, the implicit integration method is the most likely technique for real time environments, since it allows large time steps for cloth simulation by ensuring the stability of systems. However the most critical flaw of the implicit method is that it involves a large linear system. The paper presents a fast animation technique for animating soft objects based on a mass-spring model with an approximated implicit method which does not involve linear system solving. The proposed technique stably updates the state of n mass-points in O(n) time when the number of total springs are O(n). Because the mass-spring model shows a superelastic effect, the excessively deformed springs (i.e., super-elongated springs) should be adjusted for reality. The paper presents an efficient inverse dynamics process to adjust the super-elongated springs.
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