To improve the reconstructed image quality with a given number of sampling points, nonuniform sampling is desired which adapts the sampling density according to the local bandwidth of the signal. Determination of opti...
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ISBN:
(纸本)0819418587
To improve the reconstructed image quality with a given number of sampling points, nonuniform sampling is desired which adapts the sampling density according to the local bandwidth of the signal. Determination of optimal sampling positions and interpolation from nonuniform samples through the use of a coordinate mapping which converts nonuniform samples into points on a regular sampling lattice. We then introduce a nonuniform sampling scheme which embeds the samples in a generally deformed mesh structure that can be easily mapped to a regular sampling lattice. The optimal samples or the mesh is generated by minimizing the interpolation error. The numerical difficulty associated with dealing with nonuniform samples are circumvented by mapping all the operations to the master domain where the samples are uniformly distributed. With this scheme, in order to maintain the mesh topology, unnecessary nodes are usually allocated in large but smooth regions. For an improved sampling efficiency, a hierarchial nonuniform sampling scheme is also developed. Which embeds the samples in a generalized quadtree structure. Compared to its nonhierarchical counterpart, this scheme can reduce the numbers of samples significantly, under the same visual quality constraint.
A great deal of research has been devoted to generating 3D tree shapes by simulating tree growth to obtain realistic yet imaginary tree shapes. In order to display an actual scene in 3D computer graphics, 3D tree shap...
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ISBN:
(纸本)0819418587
A great deal of research has been devoted to generating 3D tree shapes by simulating tree growth to obtain realistic yet imaginary tree shapes. In order to display an actual scene in 3D computer graphics, 3D tree shapes of actual trees are necessary. Currently, despite considerable research on 3D shape reconstruction of objects from their silhouettes, the existing methods have so far been unable to handel complicated shape objects like trees whose silhouettes have a lot of occlusions. In this paper, we propose an algorithm for reconstructing 3D tree shapes based on fractal geometry, and show some experimental results.
This paper describes picture information transmission for portable multimedia terminals. The radio links used in portable multimedia terminals have narrower channel capacity and higher transmission error rates than wi...
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ISBN:
(纸本)0819418587
This paper describes picture information transmission for portable multimedia terminals. The radio links used in portable multimedia terminals have narrower channel capacity and higher transmission error rates than wired links such as those used in ISDN. To transmit multimedia information of satisfactory quality over radio links, robustness against radio link errors must be improved, because picture deterioration is much more apparent than audio deterioration. First, the effects of transmission errors on picture quality are analyzed using the H.261 coding system used for ISDN picture communication. Second, the relationship among bit error rate, terminal velocity, and picture quality is analyzed and the deterioration mechanisms of picture quality are discussed. Three techniques for improving picture quality against radio link errors are proposed.
A novel method for range image segmentation is presented in this paper, It is based on an integration of edge and region information. The algorithm consists of three steps: edge and critical point detection, triangula...
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ISBN:
(纸本)0819418587
A novel method for range image segmentation is presented in this paper, It is based on an integration of edge and region information. The algorithm consists of three steps: edge and critical point detection, triangulation, and region information. The edge detection method presented in this paper is based on morphological operations. In general, segmentation may not be effective when only edge operators are applied on range images especially on noisy images. Further processing is important for final segmentations when the edge operators are not sufficient. In this paper, critical points are extracted from planar edge curves. These edge curves and critical points constitute an initial set of segments. The constrained Delaunay triangulation is employed on the initial set to obtain triangle-like connection graphs. By projecting the critical points and their connectivity relationships in parallel onto 3D surface, a 3D surface structure graph (SSG) is obtained. Hence, segmentation is completed by grouping these triangle-like facets. The grouping scheme is presented in this paper according to the normals of adjacent facets. Because edge curves are not usually straight lines but rather a set of curve segments, we introduce extensive triangulation for building 3D triangle-like surface structure graphs (SSG's). This method significantly reduces the computation complexity compared to polyhedral approximations using the original Delaunay triangulation. Experimental results show that the method is efficient for range image segmentation especially for polyhedra.
The purpose of this paper is to introduce a new vector quantizer (VQ) which takes place in a temporal-adaptative coding scheme for the compression of digital image sequences. Our approach, which has to perform a fast ...
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ISBN:
(纸本)0819418587
The purpose of this paper is to introduce a new vector quantizer (VQ) which takes place in a temporal-adaptative coding scheme for the compression of digital image sequences. Our approach, which has to perform a fast codebook construction, unify both efficient coding methods: a fast lattice encoding and an unbalanced tree-structured codebook design according to a distortion vs. rate tradeoff. Moreover, this tree-structured lattice vector quantizer (TSLVQ) has a convenient property: because of its lattice structure, no reproduction vectors have to be transmitted. Briefly this TSLVQ technique is based on the hierarchical packing of embedded truncated lattices. We investigate here its design: by, first, explaining how to determine the support lattice and secondly how to obtain the hierarchical set of truncated lattice structures which can be optimally embedded with respect to the hierarchical packing. We then use a simple quantization procedure and describe the corresponding tree-structured codebook. Finally we present two unbalanced tree-structured codebook design algorithms based on the BFOS distortion vs. rate criterion.
The proceedings contains 112 papers. Topics discussed include application of neural networks in system identification, VLSI methodology, fading channel communications, electric power distribution, harmonics, nonlinear...
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The proceedings contains 112 papers. Topics discussed include application of neural networks in system identification, VLSI methodology, fading channel communications, electric power distribution, harmonics, nonlinear control systems, microwave amplifiers, computer vision, artificial intelligence, discrete event systems, visual computing and communications, telecommunication networks, digital signal processing, waveguides, parallel processing, imageprocessing, rectifiers and inverters, speech processing, microwave measurements, multimedia and software programming, current control methods, microwave components and systems.
Commercial analog television was standardized over fifty years ago, mainly for entertainment, sports, and news, using over the air broadcast. It is only recently that technology of compression, integrated circuits, fi...
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The recent advances in autonomous underwater vehicle (AUV) technology and underwater acoustic communications have spawned a considerable amount of research activity within the area of signal and information processing...
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The recent advances in autonomous underwater vehicle (AUV) technology and underwater acoustic communications have spawned a considerable amount of research activity within the area of signal and information processing. AUV's equipped with video hardware can provide invaluable visual data to ocean researchers for exploration of the undersea environment. In the past, a popular medium for the transport of underwater video from the vehicle to a remote platform has been a fiber optic link. Such tethered AUV's have a limited range of exploration, therefore an idea has recently been proposed to capture and process video on-board an untethered vehicle then transmit it using underwater telemetry. Video communication requires a considerably larger bandwidth than that which an underwater acoustic channel may provide therefore massive data compression must take place prior to transmission from the AUV. This work addresses the compression problem by presenting a wavelet-based hybrid video encoder for low bit-rate encoding of underwater video. Results show that compression rates on the order of 100:1 may be achieved with good visual quality in the reconstructed video.
In this parallel surface rendering algorithm based on dividing cube2 on a SIMD machine MasPar MP-1, we address the problem of load balancing and image composition. We divide a 3D array of Nx x Ny x Nz volume data into...
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ISBN:
(纸本)0819417572
In this parallel surface rendering algorithm based on dividing cube2 on a SIMD machine MasPar MP-1, we address the problem of load balancing and image composition. We divide a 3D array of Nx x Ny x Nz volume data into Nx x Ny columns, each Nz deep. Each processor in the mesh receives a subvolume of such data columns. All processors synchronously traverse its subvolume to determine the voxels intersecting the isosurface. Intersecting voxels are called isovoxels. Partial load balancing distributes the isovoxels contained in a row of processors evenly among the processors in that row to reduce the network traffic and complexity of the rendering phase. Each isovoxel is subdivided into point primitives using dividing cube algorithm. Rendering algorithm transforms the surface points and their normals and projects them into the view plane.
Recently, some speech recognition methods using fusion of visual and auditory information have been researched. In this paper, a study on the mouth shape image suitable for fusion of visual and auditory information ha...
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Recently, some speech recognition methods using fusion of visual and auditory information have been researched. In this paper, a study on the mouth shape image suitable for fusion of visual and auditory information has been described. Features of mouth shape which are extracted from gray level image and binary image are adopted, and speech recognition using linear combination method has been performed. From results of speech recognition, the studies on the mouth shape features which are effective in fusion of visual and auditory information have been performed. And the effectiveness of using two kinds of mouth shape features also has been confirmed.
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