The paper addresses the problem of interactive visualization in the view-dependent simplification framework. A geomorphing algorithm for interpolation between different levels of detail is given. The interpolation par...
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The paper addresses the problem of interactive visualization in the view-dependent simplification framework. A geomorphing algorithm for interpolation between different levels of detail is given. The interpolation parameter is derived from the screen-space geometric error instead of assigning a fixed transition time to the interpolation process. Furthermore, a hybrid frame rate control system is proposed. Frame time is predicted based on the average rendering time per triangle, reducing oscillation and overshooting. A set of experiments demonstrates the advantages of both methods.
The paper presents the extension of an audio watermarking approach to the blind detection of multiple watermarks. The underlying statistical watermarking method working in the Fourier domain with different test functi...
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ISBN:
(纸本)0769512844
The paper presents the extension of an audio watermarking approach to the blind detection of multiple watermarks. The underlying statistical watermarking method working in the Fourier domain with different test functions is investigated. The extension of this semiprivate watermarking method to enable blind detection is presented. To enable the embedding of multiple watermarks, the algorithm distributes the different watermarks in individual frequency bands. Several experiments verify the theory and show the different robustness levels of the watermarks. Enhancements and variations of the algorithm are discussed.
We propose to incorporate a priori geometric constraints in a 3-D stereo reconstruction scheme to cope with the many cases where image information alone is not sufficient to accurately recover 3-D shape. Our approach ...
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ISBN:
(纸本)0769511430
We propose to incorporate a priori geometric constraints in a 3-D stereo reconstruction scheme to cope with the many cases where image information alone is not sufficient to accurately recover 3-D shape. Our approach is based on the iterative deformation of a 3-D surface mesh to minimize an objective function. We show that combining anisotropic meshing with a nonquadratic approach to regularization enables us to obtain satisfactory reconstruction results using triangulations with few vertices. Structural or numerical constraints can then be added locally to the reconstruction process through a constrained optimization scheme. They improve the reconstruction results and enforce their consistency with a priori knowledge about object shape. The strong description and modeling properties of differential features make them useful tools that can be efficiently used as constraints for 3-D reconstruction.
The majority of virtual endoscopy techniques tries to simulate a real endoscopy. A real endoscopy does not always give the optimal information due to the physical limitations it is subject to. In this paper, we deal w...
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ISBN:
(纸本)9780780372009
The majority of virtual endoscopy techniques tries to simulate a real endoscopy. A real endoscopy does not always give the optimal information due to the physical limitations it is subject to. In this paper, we deal with the unfolding of the surface of the colon as a possible visualization technique for diagnosis and polyp detection. A new two-step technique is presented which deals with the problems of double appearance of polyps and nonuniform sampling that other colon unfolding techniques suffer from. In the first step, a distance map from a central path induces nonlinear rays for unambiguous parameterization of the surface. The second step compensates for locally varying distortions of the unfolded surface. A technique similar to magnification fields in information visualization is hereby applied. The technique produces a single view of a complete, virtually dissected colon.
In this paper, we extend our previous work (Proc. computer Animation and Simulation, pp. 125-135, Aug. 2000) and propose a muscle model that is suitable for computergraphics based on physiological and anatomical cons...
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In this paper, we extend our previous work (Proc. computer Animation and Simulation, pp. 125-135, Aug. 2000) and propose a muscle model that is suitable for computergraphics based on physiological and anatomical considerations. Muscle motion and deformation is automatically derived from one or several action lines, each action line being deformed by a 1D mass-spring system. The resulting model is fast, can accommodate most superficial human muscles, and could easily be integrated into current modeling packages. Example animations can be found at .
We present an algorithm for visibility preprocessing of urban environments. The algorithm uses a subdivision of line space to analytically calculate a conservative potentially visible set for a given region in the sce...
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We present an algorithm for visibility preprocessing of urban environments. The algorithm uses a subdivision of line space to analytically calculate a conservative potentially visible set for a given region in the scene. We present a detailed evaluation of our method, including a comparison to another recently published visibility preprocessing algorithm. To the best of our knowledge, the proposed method is the first algorithm that scales to large scenes and efficiently handles large view cells.
The transition from traditional graphics into computergraphics over the past decade has brought about a multitude of changes which graphic educators and other graphic professionals have had to address and incorporate...
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The transition from traditional graphics into computergraphics over the past decade has brought about a multitude of changes which graphic educators and other graphic professionals have had to address and incorporate into their curriculum or industry. The ever evolving integration of computer aided design (CAD) into the architectural and engineering areas have revolutionized the design and construction documentation process. But, when is it cost effective to utilize 2D, 3D or 4D CAD in the construction documentation processes or in business practice? A problem that most professionals are encountering is when to utilize the most technology has to offer and when to get by with minimal standards. This paper discusses the components of 2D, 3D and 4D CAD in construction communication documentation and when professionals and educators should utilize these different types of drawings.
We present a new method to visualize virtual endoscopic views. We propose to flatten the organ by the direct projection of the surface onto a set of cylinders. Two sampling strategies are presented and the introduced ...
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Detecting the presence of people and suspicious objects are the essential tasks for security surveillance. This paper presents a new real-time system for this purpose. Two motion cues from background subtraction and t...
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ISBN:
(纸本)0780371011
Detecting the presence of people and suspicious objects are the essential tasks for security surveillance. This paper presents a new real-time system for this purpose. Two motion cues from background subtraction and temporal differencing are employed to not only get reliable motion detection but also identify detected objects in the scene. A fuzzy reasoning technique is developed to detect and locate motion objects from vertical projection of motion cues. The background model is updated on both pixel level and region level to adapt both slow illumination changes and sudden extraneous events. This new background maintenance technique makes the system to be able to work under varying environments. The system has been run round the clock in real scene and the performance is very promising.
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