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Proceedings of the IEEE Workshop on Visual Motion

7-9 Oct. 1991

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Displaying Results 1 - 25 of 47
  • Estimation of velocity, acceleration and disparity in time sequences

    Publication Year: 1991, Page(s):44 - 51
    Cited by:  Papers (9)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1048 KB)

    The paper presents a general framework for the analysis of time sequences. Features extracted include speed, acceleration and disparity/depth. The method uses spatio-temporal filtering in a hierarchical structure. Synthetic and real world examples are included.<> View full abstract»

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  • Proceedings of the IEEE Workshop on Visual Motion (Cat. No.91TH0390-5)

    Publication Year: 1991
    Request permission for commercial reuse | PDF file iconPDF (1465 KB)
    Freely Available from IEEE
  • Incremental estimation of image-flow using a Kalman filter

    Publication Year: 1991, Page(s):36 - 43
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (580 KB)

    Many applications of visual motion, such as navigation, tracking, etc., require that image-flow be estimated in an on-line, incremental fashion. Kalman filtering provides a robust and efficient mechanism to record image-flow estimates along with their uncertainty and to integrate new measurements with the existing estimates. The fundamental form of motion information in time-varying imagery (conse... View full abstract»

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  • Motion tracking on the spatiotemporal surface

    Publication Year: 1991, Page(s):340 - 345
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (612 KB)

    The spatiotemporal (ST) surface has been shown to be a useful representation of projected scene dynamics. The authors previous use of this representation has focused on geometric recovery of scene static structure from the analysis of relative motions on the moving image plane. That earlier work (Int. J. of Comput. Vis., vol.2, no.1, p.51-72 (1989); p.33-50, (1989); vol.1, no.1, p.7-55 (1987)), ex... View full abstract»

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  • Stability of phase information

    Publication Year: 1991, Page(s):52 - 60
    Cited by:  Papers (3)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (696 KB)

    This paper concerns the robustness of phase information for measuring image velocity and binocular disparity, its stability with respect to geometric deformations, and its linearity as a function of spatial position. These properties are shown to depend on the form of the filters used and their frequency bandwidths. The authors also discuss situations in which phase is unstable, many of which can ... View full abstract»

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  • Direct computation of the focus of expansion from velocity field measurements

    Publication Year: 1991, Page(s):146 - 155
    Cited by:  Papers (266)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (672 KB)

    A new method for computing the direction of translational motion (focus of expansion) of a moving observer (or camera) in a stationary environment is proposed. The method applied simple 1D search directly to velocity field measurements of the changing image, for cases of general motion and constrained motion. In the case of general motion, the velocity field is derotated to cancel the velocity of ... View full abstract»

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  • Simultaneous estimation of 3D shape and motion of objects by computer vision

    Publication Year: 1991, Page(s):256 - 261
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (580 KB)

    A recursive estimation method based on the 4D-approach to real-time computer vision for simultaneously determining both 3D shape parameters and motion state of objects is discussed. The recognition processes exploit structurally given shape models and motion models given by difference-equations. This allows to confine the image analysis to feature evaluation of the last frame of the sequence only;... View full abstract»

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  • Mechanisms for isolating component patterns in the sequential analysis of multiple motion

    Publication Year: 1991, Page(s):187 - 193
    Cited by:  Papers (21)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (572 KB)

    Pyramid techniques are commonly used to provide computational efficiency in the analysis of image motion. But these techniques can play an even more important role in the analysis of multiple motion, where, for example, a transparent pattern moves in front of a differently moving background pattern. The pyramid framework then separates motion components based on their spatial and temporal frequenc... View full abstract»

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  • Recursive estimation of shape and nonrigid motion

    Publication Year: 1991, Page(s):306 - 311
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (536 KB)

    The authors paper presents an approach for recursively estimating 3D object shape and general nonrigid motion, which makes use of physically based dynamic models. The models provide global deformation parameters which represent the salient shape features of natural parts, and local deformation parameters which capture shape details. The equations of motion governing the models, augmented by point-... View full abstract»

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  • Estimating 3D vehicle motion in an outdoor scene from monocular and stereo image sequences

    Publication Year: 1991, Page(s):62 - 68
    Cited by:  Papers (4)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (504 KB)

    The main goal of this research is to test how well existing feature extraction, matching and motion estimation algorithms (with appropriate modification) work on outdoor scenes. For this purpose, a careful calibrated image sequence data base has been created. The data used for the results reported in the paper consists of a sequence of 24 stereo images of an outdoor scene containing a moving truck... View full abstract»

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  • Segmentation, matching and estimation of structure and motion of textured piecewise planar surfaces

    Publication Year: 1991, Page(s):274 - 279
    Cited by:  Papers (4)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (496 KB)

    The authors present an algorithm which segments and matches the regions and then estimates non-iteratively 3D motion and structure of a moving piecewise planar textured surface from two perspective views. The algorithm has two major steps. The first step is coarse. Here, the local planar nature of the surface is used to obtain polynomial expressions for image plane displacements of features. Using... View full abstract»

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  • Quantitative interpretation of image velocities in real time

    Publication Year: 1991, Page(s):211 - 216
    Cited by:  Papers (6)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (620 KB)

    A concept for motion stereo is introduced. It is based on an explicit determination of the velocities with which features move in images of dynamic scenes. A mobile robot carrying a single TV-camera may use this method to determine its distance to external objects accurately and in real time. While the robot approaches an object the accuracy of the measurement improves continuously as the distance... View full abstract»

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  • Forming a three dimensional environment model using multiple observations

    Publication Year: 1991, Page(s):262 - 267
    Cited by:  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (456 KB)

    An autonomous navigating agent must form a three-dimensional model of its environment using passive sensors. Typical stereo algorithms produce sparse depth maps and cannot be used to distinguish between holes and solid objects in the environment. The authors present a novel methodology for creating a three-dimensional model of the environment. They divide the environment into a set of disjoint cel... View full abstract»

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  • Robust estimation of a multi-layered motion representation

    Publication Year: 1991, Page(s):173 - 178
    Cited by:  Papers (62)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (456 KB)

    In order to recover an accurate representation of a scene containing multiple moving objects, one must use estimation methods that can recover both model parameters and segmentation at the same time. Traditional approaches to this problem rely on an edge-based discontinuity model, and have problems with transparent phenomena. The authors introduce a layered model of scene segmentation based on exp... View full abstract»

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  • Relative depth from motion using normal flow: an active and purposive solution

    Publication Year: 1991, Page(s):196 - 204
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (672 KB)

    The authors show how an active observer can compute the relative depth of (stationary or moving) objects in the field of view using only the spatiotemporal derivatives of the time varying image intensity function. The solution they propose is purposive in the sense that it solves only the relative depth from motion problem and cannot be used for other problems related to motion; active in the sens... View full abstract»

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  • Direct multi-resolution estimation of ego-motion and structure from motion

    Publication Year: 1991, Page(s):156 - 162
    Cited by:  Papers (42)  |  Patents (21)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (580 KB)

    The paper describes an iterative algorithm that estimates the motion of a camera through an environment directly from brightness derivatives of an image pair. A global ego-motion constraint is combined with the local brightness constancy constraint to relate local surface models with the global ego-motion model and local brightness derivatives. In an iterative process, the author first refines the... View full abstract»

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  • Computing motion using analog VLSI vision chips: an experimental comparison among four approaches

    Publication Year: 1991, Page(s):312 - 324
    Cited by:  Papers (17)  |  Patents (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1172 KB)

    The authors have designed, built and tested a number of analog CMOS VLSI circuits for computing 1D motion from the time-varying intensity values provided by an array of on-chip phototransistors. The authors present experimental data for three such circuits and discuss their relative performance. One circuit approximates the correlation model, one the gradient model, while a third chip uses resisti... View full abstract»

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  • Recovering a boundary-level structural description from dynamic stereo

    Publication Year: 1991, Page(s):69 - 74
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (676 KB)

    The authors present a stereo algorithm to recursively compute a boundary-level structural description of a scene, from a sequence of stereo images. This algorithm utilizes connected line segments as the basic match primitive, which yields a description composed primary of boundaries of objects in the scene. A description of this nature is very useful for obstacle avoidance and path planning for mo... View full abstract»

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  • Hierarchical feature based matching for motion correspondence

    Publication Year: 1991, Page(s):280 - 285
    Cited by:  Papers (3)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (560 KB)

    The authors design a feature based motion correspondence system. They propose a hierarchical grouping process that groups line segments into more complex structures that are easier to match. The hierarchy consists of lines, vertices, edges and surfaces. Matching starts at the highest level of the hierarchy (surfaces) and proceeds to the lowest (lines). Higher level features are easier to match, be... View full abstract»

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  • A new approach to vision and control for road following

    Publication Year: 1991, Page(s):217 - 225
    Cited by:  Papers (17)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (636 KB)

    The paper deals with a new, quantitative, vision-based approach to road following. It is based on the theoretical framework of the recently developed optical flow-based visual field theory. By building on this theory, the authors suggest that motion commands can be generated from a visual feature, or cue, consisting of the projection into the image of the tangent point on the edge of the road, alo... View full abstract»

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  • 3D structure reconstruction from an ego motion sequence using statistical estimation and detection theory

    Publication Year: 1991, Page(s):268 - 273
    Cited by:  Papers (6)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (516 KB)

    The paper discusses the problem of estimating 3D structures from an extended sequence of 2D images taken by a moving camera with known motion. The work is mainly concerned with sparse line features and thus is a natural extension of the feature-based motion analysis paradigm. Usually such a paradigm involves several separate operations: feature detection, feature matching, structure/motion estimat... View full abstract»

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  • Motion-boundary illusions and their regularization

    Publication Year: 1991, Page(s):88 - 94
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (632 KB)

    The authors performed several experiments where they made sure that the only cues available to the observer were contour and motion. It turns out that when humans combine information from contour and motion to reconstruct the shape of an object in view, if the results of the two modules-shape from contour and structure from motion-are inconsistent, they totally discard one of the cues and an illus... View full abstract»

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  • Parallel visual motion analysis using multiscale Markov random fields

    Publication Year: 1991, Page(s):30 - 35
    Cited by:  Papers (11)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (516 KB)

    The use of Markov Random Field (MRF) models within the framework of global bayesian decision has brought new powerful solutions to visual motion analysis. The efficiency of MRF models for image sequence analysis has been proved on various classes of real-world sequences: outdoor and indoor scenes including several moving objects and camera motion. The authors extend this work by investigating new ... View full abstract»

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  • Adaptive coring techniques for spatio-temporal signals

    Publication Year: 1991, Page(s):333 - 339
    Cited by:  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (908 KB)

    Coring is a nonlinear filtering technique traditionally used by television engineers to reduce the perceptibility of noise in the luminance signal. The author presents a generalization to coring on an oriented 3D decomposition of spatio-temporal signals, along with a psychophysically based method for adaptively setting the shape of the nonlinear coring function at each point in time and space. Noi... View full abstract»

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  • Egomotion from global flow field data

    Publication Year: 1991, Page(s):140 - 145
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (404 KB)

    The author presents two independent, global algorithms to compute the motion parameters. The flow circulation algorithm fits a linear surface to the curl of the flow field. The parameters of this linear surface are proportional to the angular velocity components. The author shows that instead of the curl values one can use circulation values that are simply contour integrals of the flow field on t... View full abstract»

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