An automatic smooth surface connection method that has the capability of tension control is presented. Given two trimmed NURBS surfaces, the new method constructs a smooth connection surface to connect the trimming re...
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An automatic smooth surface connection method that has the capability of tension control is presented. Given two trimmed NURBS surfaces, the new method constructs a smooth connection surface to connect the trimming regions of the trimmed surfaces at the trimming curves. The connection satisfies the pseudo-G1 or pseudo-C1 smoothness requirement, a condition not as strong as G1 or C1, but smooth enough for most industrial applications. The construction process consists of four major steps: connection curves construction and alignment, initial blends construction, setting up continuity constraints, and internal and external boundary smoothing. The advantages of the new method include: (1) providing the users with more flexibility in adjusting the shape of the connection surface, (2) the representation of the connection surface is compatible with most of the current data-exchange standards, (3) including the classical blending as a special case but with more flexib ility on the setting of the rail curves, and (4) smoother shape of the resulting connection surface through an energy optimization process. Test cases that cover important applications are included.
The growth of the brain of a human embryo changes over a long period of time in the body of the mother. So it is very difficult to observe and to understand that process. Therefore, embryologists have found realistic ...
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The proper usage and creation of transfer functions for time-varying data sets is an often ignored problem in volume visualization. Although methods and guidelines exist for time-invariant data, little formal study fo...
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We consider the problem of maintaining connected components in a set of moving objects using the kinetic data structure (KDS) framework. We assume that the motion of each object can be specified by a low-degree algebr...
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Light fields (or Lumigraphs) are an image-based rendering method. As light fields require a large number of images, memory and disk space requirements are a significant barrier to the practical use of light fields. In...
Light fields (or Lumigraphs) are an image-based rendering method. As light fields require a large number of images, memory and disk space requirements are a significant barrier to the practical use of light fields. In this paper, we explain how to greatly reduce the space demands of light fields by encoding them in an MPEG format. The encoding is comprised of an MPEG bitstream and two tables of precomput ed information to aid real-time decoding. By restricting the parameters used for MPEG encoding, and by employing a caching system, new views of the compressed light field can be rendered at fast interactive frame rates on consumer hardware. Compression ratios of around 50:1 are demonstrated. Combined, the speed and compression make the use of light fields practical on consumer hardware.
Three-dimensional rotational angiography (3DRA) is a promising imaging technique which yields high-resolution isotropic 3D images of vascular structures. Raw 3DRA images, however, usually suffer from a high noise leve...
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The estimation of limb segment pose from range data streams through homogeneous factorization was performed. The technique accounted for skin deformation error by providing an estimate of the shape of the limb segment...
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The estimation of limb segment pose from range data streams through homogeneous factorization was performed. The technique accounted for skin deformation error by providing an estimate of the shape of the limb segment built up from a linear combination of multiple basis shapes. The technique allowed for the choice of the number of basis shapes and automatically extracts the limb segment location, orientation and shape.
We present a modification of the Mumford-Shah functional and its cartoon limit which allows the incorporation of statistical shape knowledge in a single energy functional. We show segmentation results on artificial an...
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ISBN:
(纸本)076951278X
We present a modification of the Mumford-Shah functional and its cartoon limit which allows the incorporation of statistical shape knowledge in a single energy functional. We show segmentation results on artificial and real-world images with and without prior shape information. In the case of occlusion and strongly cluttered background the shape prior significantly improves segmentation. Finally we compare our results to those obtained by a level-set implementation of geodesic active contours.
Many optimization problems on weighted graphs seek a subset of the graph's edges that has minimum weight and satisfies the problem's constraints. Two examples are the traveling salesman problem (TSP) and the d...
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Image transmission over low-bandwidth channels can be speeded up if the image coding mechanism supports regions of interest (RoIs). By such a scheme, image parts not belonging to RoIs can be encoded at a lower bitrate...
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Image transmission over low-bandwidth channels can be speeded up if the image coding mechanism supports regions of interest (RoIs). By such a scheme, image parts not belonging to RoIs can be encoded at a lower bitrate. This paper describes a flexible dynamic RoI scheme which supports the definition of arbitrarily-shaped RoIs before the start of the transmission process and the refinement of a partially transmitted image by the definition of new RoIs at any time during image transmission. The overhead to represent RoIs is kept as small as possible by exploiting a polygon-based RoI representation. Span arithmetic on a multiresolution grid is used to support the redundancy-free transmission of overlapping RoIs.
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