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SPIE conference on Mathematical Methods in Geophysical Imaging V

作者： Donoho, PL Ergas, RA Polzer, RS Chevron Petr Technol Co La Habra CA 90631 USA

ISBN: (纸本)0819429082

As new methods of interpreting 3D seismic data, particularly prestack and derived attribute data, increase in popularity, the management of ever-larger data volumes becomes critical. Compared with acquisition and processing, however, the interpretation use of seismic data requires faster and non-sequential, random access to large data volumes. In addition, quantitative interpretations lead to an increasing need for full 32-bit resolution of amplitudes, rather than the 8 or 16 bit representations that have been used in most interpretation systems up to the present. Seismic data compression can be a significant tool in managing these on-line datasets, but the implementations previously used (e.g. Donoho, et al. 1995) are not well suited to providing rapid random access in arbitrary directions (CDP, crossline, timeslice). If compression ratios of twenty or greater can be routinely provided, with full random access to all parts of the dataset, then both larger cubes and more cubes can be handled within the finite memory and disk systems available on interpretation systems. Such on-line data accessibility will lead to higher productivity by interpreters and greater value for existing seismic surveys. We address here several problems that arise when using the lossy wavelet-transform data compression algorithms currently available. We demonstrate that wavelet compression introduces less noise than currently accepted truncation compression. We also show how compressing small blocks of data needed for random access leads to artifacts in the data, and we provide a procedure for eliminating these artifacts.

关键词： Data compression signal to noise ratio wavelets Data acquisition Data storage Data centers Algorithms image compression Wavelet transforms 3D acquisition

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Design of diffractive phase elements that implement axial-intensity modulations with conjugate gradient algorithm

Design of diffractive phase elements that implement axial-in...

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conference on Diffractive and Holographic Device Technologies and applications V

作者： Liu, R Gu, BY Dong, BZ Yang, GZ Acad Sinica Inst Phys Beijing 100080 Peoples R China

ISBN: (纸本)0819427306

We employ conjugate gradient algorithm for designing diffractive phase elements (DPEs) that implement the predefined axial-intensity modulations over a given region. We introduce an error function used for guiding the design of DPEs and appraising their performance. We derive the analytical expression for the gradient of the error function with respect to the phases of DPEs. To demonstrate effectiveness of the related algorithm, we carry out model designs of several DPEs that realize different axial-intensity modulations. For instance, we achieve the designs of the DPEs for focusing incident uniform wave into four foci with equal or unequal spacing between the consecutive foci along the optical axis, and the DPE for realizing sinusoid-like axial-intensity modulation over a given region. We also present the designs of the DPEs for generating pseudo-nondiffracting beams with multiple-segment character. The results show that the designed DPEs can satisfactorily fulfill the practical requirements.

关键词： diffractive phase element conjugate gradient method axial-intensity modulation signal and image processing

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VORTEx: video retrieval and tracking from compressed multimedia databases - affine transformation and occlusion invariant tracking from MPEG-2 video

VORTEX: video retrieval and tracking from compressed multime...

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7th Storage and Retrieval for image and Video Databases conference

作者： Schonfeld, D Lelescu, D Univ Illinois Dept EECS Signal & Image Res Lab Chicago IL 60680 USA

ISBN: (纸本)0819431273

In this paper, we present topics related to tracking of video objects in compressed video databases in the context of video retrieval applications. We developed a video retrieval and tracking system (VORTEx) to enable operation directly on compressed video data. The structure of the video compression standards is exploited in order to avoid the costly decompression operation. This is achieved by utilizing motion compensation-a critical prediction filter embedded in video compression standards-to estimate and interpolate the desired method for template matching. Occlusion analysis, filtering and motion analysis are used to implement fast tracking of objects of interest on the compressed video data. Being presented with a query in the form of template images of objects, the system operates on the compressed video in order to find the images or video sequences where those objects are present and their positions in the image. This enables the retrieval and display of the query-relevant sequences.

关键词： video retrieval compressed multimedia databases compressed domain processing motion analysis occlusion MPEG

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Coded imaging of fusion neutrons in inertial confinement fusion experiments

Coded imaging of fusion neutrons in inertial confinement fus...

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International conference on applications of Photonic Technology (ICAPT 98)

作者： Delage, O Savale, B Arsenault, HH Commissariat Energie Atom F-91680 Bruyeres Le Chatel France

ISBN: (纸本)0819429503

In Inertial Confinement Fusion (ICF) experiments, radiation from the compressed core is increasingly reabsorbed. For the largest experiments, the only radiation to escape is the 14 MeV fusion neutrons to which we must turn to learn of the physical processes taking place. The most important parameters are the shape and the size of the compressed core and this involves imaging the neutrons produced by the fusion reactions. The penumbral technique is ideally suited to neutron imaging and the feasibility of this technique has been demonstrated at the Lawrence Livermore National Laboratory (LLNL) in the United States(3). At the Phebus laser facility in France(1,2), this method has been used to image compressed ICF cores with diameters of 150 mu m yielding approximately 10(9) neutrons, and the overall spatial resolution obtained in the reconstructed source was approximately 100 mu m. On the Laser Megajoule project (LMJ) which is the equivalent of the National Ignition Facility (NIF) in the United States, the spatial resolution required to diagnose high-convergence targets is 10 mu m. We wish first to obtain a spatial resolution of 30 mu m to image source with a diameter less than or equal to 100 mu m at a neutron yield in the range of 10(11)-10(14) neutrons/4 pi, A collaborative experimental program with the Laboratory for Laser Energetics at the University of Rochester in this perspective is planned, At the same time, there is a research program in collaboration with Laval University (Quebec) concerning coded aperture designs and the associated reconstruction techniques. In this article we first review the basic requirements of such imagery and the concept of the penumbral imaging technique. Then we concentrate on the parameters that condition the spatial resolution and the description of our imaging system. Finally, we survey the reconstruction techniques used followed by results and comparative evaluation of those methods.

关键词： neutron penumbral imaging image processing signal-dependant noise Inertial Confinement Fusion (ICF)

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Approximate continuous wavelet transform with an application to noise reduction

Approximate continuous wavelet transform with an application...

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International conference on Acoustics, Speech, and signal processing (ICASSP)

作者： J.M. Lewis C.S. Burrus Electrical and Computer Engineering Department Rice University Houston TX USA

We describe a generalized scale-redundant wavelet transform which approximates a dense sampling of the continuous wavelet transform (CWT) in both time and scale. The dyadic scaling requirement of the usual wavelet transform is relaxed in favor of an approximate scaling relationship which in the case of a Gaussian scaling function is known to be asymptotically exact and irrational. This scheme yields an arbitrarily dense sampling of the scale axis in the limit. Similar behavior is observed for other scaling functions with no explicit analytic form. We investigate characteristics of the family of Lagrange interpolating filters (related to the Daubechies (1988) family of compactly-supported orthonormal wavelets), and finally present applications of the transform to denoising and edge detection.

关键词： Wavelet transforms Noise reduction Continuous wavelet transforms Discrete wavelet transforms Multiresolution analysis Sampling methods Application software Filters image edge detection Wavelet analysis

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An algebraic solution to the 3-D discrete tomography problem

An algebraic solution to the 3-D discrete tomography problem

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IEEE International conference on image processing

作者： A.E. Yagle Department of EECS University of Michigan Ann Arbor MI USA

Discrete tomography is the problem of reconstructing a binary image defined on a discrete lattice of points from its projections at only a few angles. It has applications in x-ray crystallography, in which the projections are the number of atoms in the crystal along a given line, and nondestructive testing. The 2-D version of this problem is fairly well understood, and several algorithms for solving it are known, most of which involve discrete mathematics or network theory. However, the 3-D problem is much harder to solve. This paper shows how the problem can be recast in a purely algebraic form. This results in: (1) new insight into the number of projection angles needed for an almost surely unique solution; (2) non-obvious dependencies in projection data; and (3) new algorithms for solving.

关键词： Tomography Atomic measurements Lattices image reconstruction signal processing algorithms Nondestructive testing Mathematics Discrete Fourier transforms x-ray imaging Crystallography

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Hierarchical Object-Oriented Video Segmentation and Representation Algorithm

Hierarchical Object-Oriented Video Segmentation and Represen...

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1998 Fourth International conference signal processing

作者： Jianping FAN Gen FUJITA Jun YU Koji MIYANOHANA Takao ONOYE Nagisa ISHIURA Lide WU Isao SHIRAKAWA Department of Information Systems Engineering Faculty of EngineeringOsaka UniversityYamadaoka 2-1SuitaOsaka 565Japan Department of Computer Science Fudan UniversityShanghai 200433China

In this paper,a novel object-oriented hierarchical video segmentation and representation algorithm is proposed based on four-component video model,where the local variance contrast and the frame difference contrast are selected for generating the 2D spatiotemporal entropy. The extracted object is first represented by a group of(4 x 4) blocks coarsely,then the intra-block edge extraction on edge blocks and the joint spatiotemporal similarity test among neighboring blocks are further performed for determining the meaningful real objects. This proposed hierarchical segmentation algorithm may be very useful for MPEG-4 applications.A novel fast algorithm is also introduced for reducing the search burden. Moreover,this unsupervised algorithm also makes the automatic image and video segmentation possible.

关键词： Object image Hierarchical Object-Oriented Video Segmentation and Representation Algorithm

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Digital filters associated with bivariate box spline wavelets

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JOURNAL OF ELECTRONIC IMAGING 1997年第4期6卷 453-466页

作者： He, WJ Lai, MJ Univ Georgia Dept Math Athens GA 30602 USA

Battle-Lemarie's wavelet has a nice generalization in a bivariate setting. This generalization is called bivariate box spline wavelets. The magnitude of the filters associated with the bivariate box spline wavelets is shown to converge to an ideal high-pass filter when the degree of the bivariate box spline functions increases to co. The passing and stopping bands of the ideal filter are dependent on the structure of the box spline function. Several possible idea! filters are shown. While these filters work for rectangularly sampled images, hexagonal box spline wavelets and filters are constructed to process hexagonally sampled images. The magnitude of the hexagonal filters converges to an ideal filter. Both convergences are shown to be exponentially fast. Finally, the computation and approximation of these filters are discussed. (C) 1997 SPIE and IS&T.

关键词： wavelets Linear filtering Digital filtering Fourier transforms image filtering Optical filters Matrices Digital signal processing image processing signal processing

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Examples of bivariate nonseparable continuous compactly supported orthonormal wavelets

Examples of bivariate nonseparable continuous compactly supp...

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conference on Wavelet applications in signal and image processing V

作者： He, WJ Lai, MJ Univ. of Georgia (United States)

We give many examples of bivariate nonseparable compactly supported orthonormal wavelets which are supported over [0,3]x[0,3]. The Holder continuity properties of these wavelets are studied.

ISBN: (纸本)0819425915

We give many examples of bivariate nonseparable compactly supported orthonormal wavelets which are supported over [0,3]x[0,3]. The Holder continuity properties of these wavelets are studied.

关键词： nonseparable compact support orthonormal continuous wavelet

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Multiresolution image modelling

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ELECTRONICS & COMMUNICATION ENGINEERING JOURNAL 1997年第2期9卷 90-96页

作者： Wilson, R Dept. of Comput. Sci. Warwick Univ. Coventry UK

A novel approach to the statistical modelling of images based on widely used multiresolution image representations, such as pyramids and wavelets, is presented. It is shown how models which are causal in the scale dimension provide an effective way of expressing the concept of successive approximation, or coarse-fine refinement, by the addition of details to the coarse structure of images. The ideas are illustrated using applications including image enhancement, data compression and segmentation.

关键词： image segmentation Pattern recognition image representation approximation theory wavelets successive approximation data compression Codes multiresolution image modelling pyramids image coding data segmentation Optical information, image and video signal processing scale dimension coarse-fine refinement Computer vision and image processing techniques wavelet transforms transform coding Other numerical methods statistical modelling coarse structure image resolution multiresolution image representation image enhancement

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