Preliminary results of a method for range view registration are presented. The method incorporates the LeRP algorithm, which is a deterministic means to approximate subgraph isomorphisms. Graphs are formed that descri...
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Preliminary results of a method for range view registration are presented. The method incorporates the LeRP algorithm, which is a deterministic means to approximate subgraph isomorphisms. Graphs are formed that describe salient scene features. Graph matching then provides the scene-to-scene correspondence necessary for registration. A graphical representation is invariant with respect to sensor standoff. Test results from real and synthetic images indicate that a reasonable tradeoff between speed and accuracy is achievable. A mean rotational error of /spl sim/1 degree was found for a variety of test cases. Mean compute times were found to be better than 2 Hz, with image sizes varying from 128/spl times/200 to 240/spl times/320. These tests were run on a 900 MHz PC The greatest challenge to this approach is the stable localization and invariant characterization of image features via fast, deterministic techniques.
We describe the goals of the ATTEST project, which started in March 2002 as part of the Information Society Technologies (IST) programme, sponsored by the European Commission. In the 2-year project, several industrial...
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We describe the goals of the ATTEST project, which started in March 2002 as part of the Information Society Technologies (IST) programme, sponsored by the European Commission. In the 2-year project, several industrial and academic partners cooperate towards a flexible, 2d-compatible and commercially feasible 3d-TV system-for broadcast environments. An entire 3d-video chain will be developed. We discuss the goals for content creation, coding, transmission, display and the central role that human 3d perception research will play in optimizing the entire chain. The goals include the development of a new 3d camera, algorithms to convert existing 2d-video material into 3d, a 2d-compatible coding andtransmission scheme for 3d video using MPEG-2/4/7, and two new autostereoscopic displays. With the combination of industrial and academic partners and the technological progress obtained from earlier 3d projects, we expect to achieve the ATTEST goal of developing the first commercially feasible European 3d-TV broadcast system.
Presents a framework of surface modeling from multi-view range data. The input to the algorithms are triangle meshes, each of which is from a single view range scan. The triangle meshes generated from raw data are fir...
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Presents a framework of surface modeling from multi-view range data. The input to the algorithms are triangle meshes, each of which is from a single view range scan. The triangle meshes generated from raw data are first processed by the proposed area decreasing flow for surface denoising. Although the proposed flow is mathematically equivalent to the mean curvature flow, it can avoid the difficulty in curvature estimation and provide an optimal flowing step size. We introduce an adaptive triangle mesh smoothing scheme based on crease edge strength of each vertex using tensor voting of the normal vector field inside a geodesic window. The smoothing result makes surface normal estimation more accurate which is then used in surface mesh integration. Based on Hilton's implicit surface-based method, surfaces from multiple views are integrated into a single 3d model. We incorporate color images to generate textured models. The algorithms are successfully applied to surface modeling from range data using two types of range scanners.
We present a method for the recovery of partially occluded3d geometric primitives from range images which might also include nonprimitive objects. The method uses a technique for estimating the principal curvatures a...
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We present a method for the recovery of partially occluded3d geometric primitives from range images which might also include nonprimitive objects. The method uses a technique for estimating the principal curvatures anddarboux frame from range images which we developed. After estimating the principal curvatures and the darboux frames from the entire scene, a search for the known patterns of these features in geometric primitives is performed. If a specific pattern is identified then the presence of the corresponding primitive is confirmed using these local features. The features are also used to recover the primitive's characteristics. The suggested application is very efficient since it combines the segmentation, classification and fitting processes, which are part of any recovery process, in a single process, which advances monotonously through the recovery procedure. The combined process does not use any least-squares fittings and therefore is very robust to inaccuracies in the local feature extraction process and to errors in segmentation. It was tested on series of real complex cluttered scenes, yielding accurate and robust recoveries of primitives.
We present an efficient image-based rendering algorithm that computes photo hulls of a scene photographed from multiple viewpoints. Our algorithm, called image-based photo hulls (IBPH), like the image-based visual hul...
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We present an efficient image-based rendering algorithm that computes photo hulls of a scene photographed from multiple viewpoints. Our algorithm, called image-based photo hulls (IBPH), like the image-based visual hulls (IBVH) algorithm from Matusik et. al. (2000) on which it is based, takes advantage of epipolar geometry to efficiently reconstruct the geometry and visibility of a scene. Our IBPH algorithm differs from IBVH in that it utilizes the color information of the images to identify the scene geometry. These additional color constraints often result in a more accurately reconstructed geometry, which projects to better synthesized virtual views of the scene. We demonstrate our algorithm running in a real-time 3d telepresence application using video data acquired from four viewpoints.
The drilling process in different materials (diamond, steel, ceramics and PMMA) was studied for a large range of pulse lengths from about 100 fs to 10 ns using different approaches. In transparent materials the penetr...
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ISBN:
(纸本)0819441376
The drilling process in different materials (diamond, steel, ceramics and PMMA) was studied for a large range of pulse lengths from about 100 fs to 10 ns using different approaches. In transparent materials the penetration process was visualized with high-speed video analysis and microscopy. The drilling rate as well as the relation between processing energy density and ablation threshold were determined in situ. The penetration of the laser beam inside the channel and the influence of laser-ignited plasma were investigated by transmission measurements. Mechanisms of energy coupling and heat losses were examined by applying simple analytical calculations. Proposals for the basic understanding of the drilling process are presented.
Urban facility management is one of the applications to which the virtual GIS is well applied. For virtual GIS to be utilized to manage urban facilities, some functionalities should be provided. One of them is how to ...
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ISBN:
(纸本)078037536X
Urban facility management is one of the applications to which the virtual GIS is well applied. For virtual GIS to be utilized to manage urban facilities, some functionalities should be provided. One of them is how to manage the huge size of 3d geographic data as compact as possible at the same time providing realistic modeling andvisualization. The other one is spatial analysis on urban facilities especially on multistorey buildings. In this paper, the synthetic modeling approach is proposed to model urban facilities realistically from the compact size of GIS data. Geographic features positioned in each storey of a building are also modeled and managed hence they are identified and queried for spatial analysis.
Wavelet methods for geometry encoding is a recently emerged superset of multiresolution analysis which has proven to be very efficient in term of compression and adaptive transmission of 3d content. The decorrelating ...
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Wavelet methods for geometry encoding is a recently emerged superset of multiresolution analysis which has proven to be very efficient in term of compression and adaptive transmission of 3d content. The decorrelating power and space/scale localization of wavelets enable efficient compression of arbitrary meshes as well as progressive and local reconstruction. Recent techniques based on zerotree compression have shown to be among the best lossy mesh compression methods, while remaining compatible with selective transmission of geometric data at various level of detail. While some progressive reconstruction schemes have been proposed in the past, we show in this paper that this representation, recently proposed in the MPEG4 standard, can be efficiently used to perform real-time, view-dependent reconstruction of large meshes. The proposed system combines algorithms for local updates, cache management and server/client dialog. The local details management is an improvement of progressive reconstructions built on top of hierarchical structures. It enables fast, homogeneous accommodation and suppression of wavelet coefficients at any level of subdivision, with time complexity independent of the size of the reconstructed mesh. The cache structure wisely exploits the hierarchical character of the receiveddata, in order to avoid redundant information transmission. The whole system enables the client to have total control on the quality of navigation according to its storage andprocessing capabilities, whatever the size of the mesh.
The following topics are dealt with: dSP for communications; adaptive filtering; multimedia over IP and wireless networks; VLSI arithmetic architectures; system level issues; digital-to-analog conversion; RF mixers; a...
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The following topics are dealt with: dSP for communications; adaptive filtering; multimedia over IP and wireless networks; VLSI arithmetic architectures; system level issues; digital-to-analog conversion; RF mixers; analog testability; interconnect modeling and optimization; blinddSP; multiple antenna systems; OFdM; cellular neural networks; stability and control; wireless communication architectures; transconductance and low-voltage amplifiers; multimedia communication andtransmission; bifurcation and chaos; FIR filters; analog-to-digital conversion; RF filters; filter theory and linear networks; communication theory; cellular neural networks; nonlinear circuit analysis; MEM devices; amplifiers, references and multipliers; hardware implementation for multimedia; image compression; multidimensional signal processing; filter banks; signal processing for communications; channel coding; pipelined AdC; circuit theory and applications; nanoelectronic integrated circuits; analog synthesis and optimization; multimedia understanding and segmentation; neural network hardware architecture; nonlinear systems modeling; sensors andprocessing circuits; audio and speech processing; active filters; numerical and combinatorial optimization; 3d graphics; image processing; smart sensors; cryptography; system-on-chip methodologies; oscillators and phase locking; operational amplifiers; multimedia watermarking; power estimation; motion estimation; chaotic circuits; wireline communication architectures; MEMS; signal processing algorithms; oversampleddata conversion; video signal processing; IIR digital filters; logarithmic and residue arithmetic; high speed VLSI circuits; self-correcting AdC; integrated inductors; fast-settling amplifiers; floor planning and placement; communication networks; adaptive signal processing; Nyquist data conversion; voltage controlled oscillators; phase locked loops; reference circuits; frequency response masking techniques; wireless architectures
To understand evolving pathology in the central nervous system (CNS) anddevelop effective treatments, it is essential to correlate the nerve fiber connectivity with the visualization of function. Such information is ...
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ISBN:
(纸本)078037584X
To understand evolving pathology in the central nervous system (CNS) anddevelop effective treatments, it is essential to correlate the nerve fiber connectivity with the visualization of function. Such information is fundamental in CNS processes since anatomical connections determine where information is passed and processeddiffusion tensor imaging (dTI) can provide the fundamental information required for viewing structural connectivity. However robust and accurate acquisition andprocessing algorithms are needed to accurately map the nerve connectivity. In this paper we present a novel, algorithm for automatic fiber tract mapping in the CNS specifically, a rat spinal cord as well as validate the mapped fibers using ex-vivo fluoro images of the excised rat. The novelty of our work lies in the fiber tract mapping as well as the validation experiment. The automatic fiber tract mapping problem will be solved in two phases, namely a data smoothing phase and a fiber tract mapping phase. In the former smoothing is achieved via a new weighted TV-norm minimization which strives to smooth while retaining all relevant detail. For the fiber tract mapping, a smooth 3d vector field indicating the dominant anisotropic direction at each spatial location is computed from the smootheddata. Fiber tracts are then determined as the smooth integral curves of this vector field in a variational framework Examples are presented for dTI data sets from a normal and injured rat spinal cords respectively.
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