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Conference on Computer Vision and Pattern Recognition (CVPR)

作者： A.M. Waxman J. Wu F. Bergholm Laboratory for Sensory Robotics College of Engineering Boston University Boston MA USA Computer Vision and Graphics Laboratory Department of Numerical Analysis and Computing Science Royal Institute of Technology Stockholm Sweden

A method is developed for the measurement of short-range visual motion in image sequences, making use of the motion of image features such as edges and points. Each feature generates a Gaussian activation profile in a spatiotemporal neighborhood of specified scale around the feature itself; this profile is then convected with motion of the feature. The authors show that image velocity estimates can be obtained from such dynamic activation profiles using a modification of familiar gradient techniques. The resulting estimators can be formulated in terms of simple ratios of spatiotemporal filters (i.e. receptive fields) convolved with image feature maps. A family of activation profiles of varying scale must be utilized to cover a range of possible image velocities. They suggest a characteristic speed normalization of the estimate obtained from each filter in order to decide which estimate is to be accepted. They formulate the velocity estimators for dynamic edges in 1-D and 2-D image sequences, as well as that for dynamic feature points in 2-D image sequences.< >

关键词： Motion measurement Image sequences Motion analysis Filters Laboratories Computer vision Robot sensing systems Educational institutions Computer graphics numerical analysis

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BOUNDS ON NONLINEAR OPERATORS IN FINITE-DIMENSIONAL BANACH-SPACES

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NUMERISCHE MATHEMATIK 1986年第1期50卷 27-44页

作者： SODERLIND, G 1.Department of Numerical Analysis and Computing Science Royal Institute of Technology S-10044 Stockholm Sweden

We consider Lipschitz-continuous nonlinear maps in finite-dimensional Banach and Hilbert spaces. Boundedness and monotonicity of the operator are characterized quantitatively in terms of certain functionals. These functionals are used to assess qualitative properties such as invertibility, and also enable a generalization of some well-known matrix results directly to nonlinear operators. Closely related to the numerical range of a matrix, the Gerschgorin domain is introduced for nonlinear operators. This point set in the complex plane is always convex and contains the spectrum of the operator's Jacobian matrices. Finally, we focus on nonlinear operators in Hilbert space and hint at some generalizations of the von Neumann spectral theory.

关键词： AMS(MOS) 47H05 47H12 65H10 65L07 CR: G1.5 G1.7

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INVESTIGATING SEMI-INFINITE PROGRAMS USING PENALTY-FUNCTIONS AND LAGRANGIAN-METHODS

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JOURNAL OF THE AUSTRALIAN MATHEMATICAL SOCIETY SERIES B-APPLIED MATHEMATICS 1986年第2期28卷 158-169页

作者： GUSTAFSON, SA Department of Numerical Analysis and Computing Science The Royal Institute of Technology S-10044 Stockholm 70 Sweden.

In this paper the relations between semi-infinite programs and optimisation problems with finitely many variables and constraints are reviewed. Two classes of convex semi-infinite programs are defined, one based on the fact that a convex set may be represented as the intersection of closed halfspaces, while the other class is defined using the representation of the elements of a convex set as convex combinations of points and directions. Extension to nonconvex problems is given. A common technique of solving a semi-infinite program computationally is to derive necessary conditions for optimality in the form of a nonlinear system of equations with finitely many equations and unknowns. In the three-phase algorithm, this system is constructed from the optimal solution of a discretised version of the given semi-infinite program. i.e. a problem with finitely many variables and constraints. The system is solved numerically, often by means of some linearisation method. One option is to use a direct analog of the familiar SOLVER method.

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COMPUTER-GRAPHICS AND COMPUTER VISION - SOME UNIFYING AND DISCRIMINATING FEATURES

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COMPUTERS & GRAPHICS-UK 1985年第4期9卷 339-349页

作者： EKLUNDH, JO KJELLDAHL, L Numerical Analysis and Computing Science Royal Institute of Technology S-10044 Stockholm Sweden

Computer graphics and computer vision deal with converse problems. In graphics the goal is to synthesize the image(s) of a scene from a given description in terms of a model or some observed data. In vision, on the other hand, the aim is to create a description of the world (the scene), given the image(s). Due to this difference of the goals the two fields have developed separately. Nevertheless, they often deal with aspects of the same physical reality. Therefore, many fundamental concepts and problems are shared by the two areas, even though the context may differ. In this paper we discuss some of the issues which unify and discriminate the fields. The purpose is not to present a self-contained presentation of the relevant notions and techniques. We refer to the existing literature for such details. Instead we try to elucidate aspects in which the two fields may benefit from each other and aspects in which this may be difficult.

关键词： COMPUTER GRAPHICS

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STABLE CONVERGENCE ACCELERATION USING LAPLACE TRANSFORMS

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NUMERISCHE MATHEMATIK 1985年第3期47卷 387-394页

作者： GUSTAFSON, SA 1.Department of Numerical Analysis and Computing Science The Royal Institute of Technology S-10044 Stockholm Sweden

We consider the general class of power series where the terms may be expressed as the Laplace transforms of known functions. The sum of the series can then be evaluated efficiently and accurately by means of quadrature schemes, recently published by Frank Stenger. The method works also far outside the region of convergence as will be illustrated by numerical examples.

关键词： AMS(MOS): 65B10 65D30 CR: G.1.4

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ON TRANSFORMATIONS OF GRADED MATRICES, WITH APPLICATIONS TO STIFF ODES

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NUMERISCHE MATHEMATIK 1985年第3期47卷 363-385页

作者： DAHLQUIST, G 1.Department of Numerical Analysis and Computing Science The Royal Institute of Technology S-100 44 Stockholm Sweden

Estimates concerning the spectrum of a graded matrix and other information useful for a reliable and efficient handling of certain complications in the numerical treatment of some stiff ODE's, can be inexpensively obtained from the factorized Jacobian. The validity of the estimates is studied by considering them as the first step in a block LR algorithm, which may be of interest in its own right. Its convergence properties are examined.

关键词： AMS(MOS): 65L05 CR: G1.3 G1.7

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RELIABILITY AND SPEED OF RECALL IN AN ASSOCIATIVE NETWORK

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IEEE TRANSACTIONS ON PATTERN analysis AND MACHINE INTELLIGENCE 1985年第4期7卷 490-498页

作者： LANSNER, A EKEBERG, O Department of Numerical Analysis and Computing Science the Royal Institute of Technology S-100 44 Stockholm Sweden

Previous investigations of the storage capacity of associative nets have not explicitly considered quantitative aspects of the tradeoff between storage capacity and reconstructive power in these systems. Furthermore, few comparisons have been made between theoretical estimates and experimental results (simulations). In this correspondence, we describe some results recently obtained and relevant to these issues. It is shown that a high storage capacity is possible, without sacrificing reliability in the recall process. Furthermore, an efficient algorithm for retrieval of the information stored is presented, and the speed of recall employing various degrees of parallelism is discussed.","doi":"10.1109/TPAMI.1985.4767688","publicationTitle":"IEEE Transactions on Pattern analysis and Machine Intelligence","startPage":"490","endPage":"498","rightsLink":"http://***/AppDispatchServlet?publisherName=ieee&publication=0162-8828&title=Reliability+and+Speed+of+Recall+in+an+Associative+Network&isbn=&publicationDate=July+1985&author=Anders+Lansner&ContentID=10.1109/TPAMI.1985.4767688&orderBeanReset=true&startPage=490&endPage=498&volumeNum=PAMI-7&issueNum=4","displayPublicationTitle":"IEEE Transactions on Pattern analysis and Machine Intelligence","pdfPath":"/iel5/34/4767672/***","keywords":[{"type":"IEEE Keywords","kwd":["Power system reliability","Pattern recognition","Neuroscience","Associative memory","Estimation theory","Information retrieval","Parallel processing","Telecommunication network reliability","Biological neural networks","Computer science"]},{"type":"Author Keywords ","kwd":["storage capacity","Associative network","pattern completion","pattern recognition","reliability of recall"]}],"allowComments":false,"pubLink":"/xpl/***?punumber=34","issueLink":"/xpl/***?isnumber=4767672","standardTitle":"Reliability and Speed of Recall in an Associative Network

关键词： Power system reliability Pattern recognition Neuroscience Associative memory Estimation theory Information retrieval Parallel processing Telecommunication network reliability Biological neural networks Computer science Author Keywords storage capacity Associative network pattern completion pattern recognition reliability of recall

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Unification problems with one-sided distributivity 1st

Unification problems with one-sided distributivity

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1st International Conference on Rewriting Techniques and Applications, RTA 1985

作者： Arnborg, Stefan Tidén, Erik Department of Numerical Analysis and Computing Science Royal Institute of Technology Stockholm 70S-100 44 Sweden

ISBN: (纸本)9783540159766

We show that unification in the equational theory defined by the one-sided distributivity law x × (y+z)=x×y+x×z is decidable and that unification is undecidable if the laws of associativity x+(y+z)=(x+y)+z and unit element 1×x=x× 1=x are added. Unification under one-sided distributivity with unit element is shown to be as hard as Markov's problem, whereas unification under two-sided distributivity, with or without unit element, is NP-hard. A quadratic time unification algorithm for one-sided distributivity, which may prove interesting since available universal unification procedures fail to provide a decision procedure for this theory, is outlined. The study of these problems is motivated by possible applications in circuit synthesis and by the need for gaining insight in the problem of combining theories with overlapping sets of operator symbols. © 1985, Springer-Verlag.

关键词： Decision theory

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Two observations on Durand-Kerner's root-finding method

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BIT numerical Mathematics 1984年第4期24卷 556-559页

作者： Kjellberg, Göran Department of Numerical Analysis and Computer Science Royal Institute of Technology Stockholm Sweden

The Durand-Kerner method is an iterative method for the simultaneous determination of all zeros of a polynomial. We derive a property of the iterates of this method, which gives one reason for its good behaviour. We also exhibit an example supporting the experience that the serial mode of the method will converge faster than the parallel mode also for multiple zeros.

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A structured approach to segmentation of aerial photographs

A structured approach to segmentation of aerial photographs

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Applications of Digital Image Processing V 1983

作者： Eklundh, Jan-Olof Department of Numerical Analysis and Computing Science Royal Institute of Technology Stockholm 70100 44 Sweden

The problem of segmenting aerial photographs can generally not be solved in a reasonable manner by use of the information in the image alone. In this paper we present a structured approach to the problem, which in addition to the image uses simple and explicit knowledge about the geometry of objects and their spatial relations. The method is relaxationlike: it works with hypotheses which are given weights and iterates to a solution. The incorporation of evidence of a hypotheses is, however, explicit and uses no complex compatibilities. The approach contains three processing levels: At the lowest level, hypotheses are formed about the material type of a pixel based on intensity and variation of intensity. At the intermediate level these hypotheses are refined into region hypotheses by use of size and shape constraints. This level is also working on pixel labels. One of the main problems is that certain regions are highly non-uniform with respect to the low-level features. Nonetheless they are welldefined by neighboring homogeneous regions. At the highest level region labels are considered. Region hypotheses are refined on the basis of relations between regions. At the present stage the method is not used for complete segmentation. Instead, it is a step to find regions that can be matched with a map. Experimental results exist mainly for the two highest levels. © 1983 Proceedings of SPIE - The International Society for Optical Engineering.

关键词： Pixels

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