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Applications of Computer Vision, Proceedings, 1992., IEEE Workshop on

Date Nov. 30 1992-Dec. 2 1992

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  • Proceedings. IEEE Workshop on Applications of Computer Vision (Cat. No.92TH0446-5)

    Publication Year: 1992
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    Freely Available from IEEE
  • A shape analysis model with applications to a character recognition system

    Publication Year: 1992 , Page(s): 182 - 189
    Cited by:  Papers (3)
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    A method for the recognition of multifont printed characters is proposed, giving emphasis to the identification of structural descriptions of character shapes using prototypes. Noise and shape variations are modeled as series of transformations from groups of features in the data to features in each prototype. Thus, the method manages systematically the relative distortion between a candidate shape and its prototype, accomplishing robustness to noise with less than two prototypes per class, on the average. Our method uses a flexible matching between components and a flexible grouping of the individual components to be matched. A number of shape transformations are defined. Also, a measure of the amount of distortion that these transformations cause is given. The problem of classification of character shapes is defined as a problem of optimization among the possible transformations that map an input shape into prototypical shapes. Some tests with hand printed numerals confirmed the method's high robustness level View full abstract»

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  • Curve recognition using B-spline representation

    Publication Year: 1992 , Page(s): 213 - 220
    Cited by:  Papers (6)  |  Patents (1)
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    The B-spline stands as one of the most efficient curve (surface) representation, and possesses very attractive properties such as spatial uniqueness, boundedness and continuity, local shape controllability, and invariance to affine transformations. These properties made them very attractive for curve representation in computer aided design and computer graphics. Very little work, however, has been devoted to them for recognition purpose. One possible reason might be due to the fact that the B-spline curve is not uniquely described by a single set of control points, which make the curve matching (recognition) process not a simple comparison between the respective parameters of the curves to be matched. The paper is an attempt to find matching solutions despite this limitation and addresses the problems of invariant matching and classification of 2D closed curves with application in identification of aircraft types based on image silhouettes, and writer-identification based on hand written text View full abstract»

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  • A visually guided mobile robot acting in indoor environments

    Publication Year: 1992 , Page(s): 180, 308 - 316
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    The paper describes the practical implementation of a vision-based navigation system for a mobile robot operating in indoor environments. The robot acquires visual information by means of three CCD cameras mounted on board. A stereo pair is used for ground plane obstacle detection and avoidance, while the third camera is used to locate landmarks and compute the robot's position. Odometric readings are used to guide visual perception by simple `where to look next' strategies. The whole processing and the control architecture determining the overall behaviour of the robot are mainly implemented on a parallel MIMD machine. Some examples are presented, showing how the robot moves in a partially structured environment reaching the specified goal points with a fair degree of accuracy, avoiding unpredicted obstacles and following trajectories obtained through the cooperation of the various navigation modules running in parallel View full abstract»

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  • Performance assessment of model-based tracking

    Publication Year: 1992 , Page(s): 28 - 35
    Cited by:  Papers (12)
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    Model-based vision techniques, originally developed for the recognition and pose recovery of vehicles in a single image, are used here to track vehicles through a sequence of images. Knowledge of the position of the camera with respect to the ground plane is used to reduce the search space of possible vehicle positions from six dimensions to three. The expected dynamics of vehicles are expressed in a Kalman filter, which predicts the likely poses in successive frames and provides a smoothed description of the vehicles' motion. The notion of equivalence classes defined by a search of the parameter space is developed as an indicator of the performance of the pose-refinement sub-system. The system is illustrated and assessed by using the size of the correct class as a performance measure View full abstract»

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  • Projectile impact detection and performance evaluation using machine vision

    Publication Year: 1992 , Page(s): 248 - 254
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    The paper reports on the development of a machine vision system for assessing targeting accuracy of ballistic, projectile-firing weapon systems. Current techniques rely on either manual optical sighting or acoustic signature to locate the point of impact. Optical sighting, still the predominant method in many events, is manual and imprecise. Acoustic-based approaches automate the process but require multiple sensor placements. The machine vision system described is able to continuously monitor the target, report precise quantitative targeting information and simultaneously provide a color-coded display of impacts. Special provisions have been built-in to account for target plane motion and overlapping impacts phenomenon View full abstract»

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  • Multiple object tracking system with three level continuous processes

    Publication Year: 1992 , Page(s): 19 - 27
    Cited by:  Papers (3)  |  Patents (5)
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    Reports a system for detecting human like moving objects in time-varying images. The authors show how it is possible to detect the image trajectories of people moving in ordinary indoor scenes. The system consists of three subprocesses: changing region detection, moving object tracking and movement interpretation. The processes are executed in parallel so hat each one can recover from the others' errors. This ensures the reliable detection of the trajectories in difficult cases such as movement across complicated backgrounds. The authors have built a trial detection system using a parallel image processing system. The details of the trial system and experimental results of walking person detection are described View full abstract»

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  • Visual processing for autonomous driving

    Publication Year: 1992 , Page(s): 164 - 171
    Cited by:  Papers (7)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (592 KB)  

    Describes a visual processing algorithm that supports autonomous road following. The algorithm requires that lane markings be present and attempts to track the lane markings on both lane boundaries. There are three stages of computation: extracting edges; matching extracted edge points with a geometric model of the road, and updating the geometric road model. All processing is confined to the 2-D image plane. No information about the motion of the vehicle is used. This algorithm has been implemented and tested using video taped road scenes. It performs robustly for both highways and rural roads. The algorithm runs at a sampling rate of 15 Hz and has a worst case latency of 139 milliseconds (ms). The algorithm is implemented under the NASA/NBS Standard Reference Model for Telerobotic Control System Architecture (NASREM) architecture and runs on a dedicated vision processing engine and a VME-based microprocessor system View full abstract»

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  • PROMAP-a system for analysis of topographic maps

    Publication Year: 1992 , Page(s): 46 - 55
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    A system for automatic data acquisition from topographic maps (PROMAP-Processing of Maps) is presented. Maps are an important source of information for efficient spatial data evaluation using Geographic Information Systems (GIS). At present a lot of relevant maps have still to be digitized manually, which is a time-consuming and error-prone process. To improve the situation, the authors developed the PROMAP-system which incorporates adequate image analyzing methods. The system is capable of generating a symbolic description of the map contents that may be imported into a GIS (e.g. ARC/INFO) View full abstract»

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  • A new methodology for isolating and diagnosing inconsistencies in image matching, as applied to the analysis of 2-D electrophoretic gels

    Publication Year: 1992 , Page(s): 197 - 204
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    An image comparison algorithm employing a new notion of match consistency has been developed for the application of mutation detection on images of two-dimensional electrophoretic gels. The application requires a very high degree of accuracy in image comparison due to the rareness of mutation. The image comparison algorithm achieves high accuracy through monitoring, isolating and diagnosing inconsistencies in the matching process. The methodology is based on algorithms for monitoring symmetry relations between match hypothesis made during the course of processing. Algorithms are given which explore violations of the basic symmetry relation. Diagnostic procedures partition symmetry violations into classes that are identified with the failure of certain essential heuristics within the comparison algorithm. This methodology provides the basis for understanding and overcoming the limitations of these heuristics in order to achieve higher accuracy View full abstract»

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  • A shadow handler in a video-based real-time traffic monitoring system

    Publication Year: 1992 , Page(s): 11 - 18
    Cited by:  Papers (66)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (876 KB)  

    A video-based system for traffic monitoring is presented. The objective of the system is to set up a high-level description of the traffic scene comprising the position, speed and class of the vehicles. Algorithms for detecting moving objects, separating the vehicles from their shadows, tracking and classification are presented. The classification of vehicles under sunny conditions is very difficult, if the shadow isn't separated from the vehicles. This approach for classification runs in real-time on low-cost hardware. the shadow can be separated from the vehicle and the knowledge about the shape of the shadow can be efficiently used. The shadow analysis algorithm itself uses high-level knowledge about the geometry of the scene (heading of the observed road) and about global data (date and time) View full abstract»

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  • Liquid crystal polarization camera

    Publication Year: 1992 , Page(s): 120 - 127
    Cited by:  Papers (9)  |  Patents (4)
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    Presents a fully automated system which unites CCD camera technology with liquid crystal technology to create a polarization camera capable of sensing the polarization of reflected light from objects at pixel resolution. As polarization affords a more general physical description of light than does intensity, it can therefore provide a richer set of descriptive physical constraints for the understanding of images. The authors present a scheme for mapping polarization states into hue, saturation and intensity which is a very convenient representation for a polarization image. The polarization camera outputs such a color image which can then be used in polarization-based vision methods. The unique vision understanding capabilities of the polarization camera system are demonstrated with experimental results showing polarization-based dielectric/metal material classification, specular reflection and occluding contour segmentations in a fairly complex scene, and surface orientation constraints for object recognition View full abstract»

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  • The RegiStar Machine: from conception to installation

    Publication Year: 1992 , Page(s): 224 - 231
    Cited by:  Patents (2)
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    The authors have developed a machine to perform the task of automatic registration of color separation films, a process manually performed by skilled professionals in the graphics arts printing industry. The development of such a machine requires overcoming significant challenges: designing a sound computer vision methodology while respecting hard timing constraints, transferring software across platforms and languages, validating the software, building the actual machine around the algorithms, testing the conformity to tolerances, educating operators on the use of such a machine, and having a system robust enough to operate around the clock with no technical supervision. The authors present a brief overview of the problem, followed by the answers they provided to the challenges above View full abstract»

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  • A segmentation-free approach to OCR

    Publication Year: 1992 , Page(s): 190 - 196
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (524 KB)  

    When confronted with degraded images of text, however, the performance of many commercial OCR systems deteriorates severely. This occurs because all these systems rely on a segmentation step that is prone to error in the presence of image noise and printing artifacts. The authors present a novel OCR approach that overcomes this problem by eliminating the segmentation step altogether. This approach is based on the concept and techniques of occluded object recognition. To achieve high efficiency as well as robustness, they incorporate the notions of indexing and voting, and tailor them to the problem of OCR. Preliminary experimental results are given View full abstract»

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  • Interactive road finding for aerial images

    Publication Year: 1992 , Page(s): 56 - 63
    Cited by:  Papers (4)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (624 KB)  

    Fully automatic road recognition remains an elusive goal in spite of many years of research. Most practical systems today use tedious manual tracing for the entry of data from satellite and aerial images to geographical data bases. The paper presents a semi-automatic method for the entry of such data. First ribbons of high contrast are found by analyzing gray scale surface principal curvatures. Then, pixels belonging to such ribbons are fitted by conic splines, and then a graph is constructed whose nodes are end points of the arcs fitted by the splines. The key new idea is to assign edges between all nodes and label them with a cost function based on physical constraints on roads. Once a pair of end points is chosen, a shortest path algorithm is used to determine the road between them. Thus a global optimization is performed over all possible candidates View full abstract»

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  • A vision system for inspection of ball bonds in integrated circuits

    Publication Year: 1992 , Page(s): 290 - 297
    Cited by:  Papers (1)
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    The paper describes a vision system for automatic inspection of the connecting part of the wire bond of an IC where the wire connects to the bond pad on the chip. It considers a popular type of such bonds known as `ball bond'. Using two-dimensional images taken from the top of the IC wafer, the system determines several geometric measures which are important in determining the quality of the bond. These measures include the boundary, length of major and minor axes of the best fitting ellipse and the center. The process utilizes automatic thresholding, morphological operations and geometric moments of the image. Success of the method is demonstrated through experimental studies on actual bonds View full abstract»

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  • Shape recovery methods for visual inspection

    Publication Year: 1992 , Page(s): 136 - 145
    Cited by:  Patents (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (888 KB)  

    The advancement of three-dimensional machine vision is closely related to the development of robust and efficient shape recovery methods. The author addresses the recovery problem associated with three different classes of surfaces: (a) specular surfaces; (b) surfaces with varying reflectance; and (c) rough and textured surfaces. Three realtime machine vision systems have been developed based on these results. Experimental results demonstrate that the proposed methods and systems are applicable to a variety of visual inspection problems View full abstract»

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  • Interpolation of cinematic sequences

    Publication Year: 1992 , Page(s): 36 - 44
    Cited by:  Papers (1)  |  Patents (1)
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    Presents a new algorithm for interframe interpolation of cinematic sequences. The authors demonstrate its applicability to video data compression of pedestrian traffic and data compression for video conferencing. In both of these applications it is assumed that the background is nearly stationary and that there are no interobject occlusions. The interpolation algorithm makes use of estimates of optical flow to compensate for the motion of objects between two frames. We describe three major problems associated with motion compensated cinematic interpolation: interframe occlusion, interframe zooming and figure-ground ambiguity. Our algorithm suppresses artifacts caused by all three of these problems View full abstract»

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  • Real time color purity and convergence measurement algorithms for automatic ITC adjustment system

    Publication Year: 1992 , Page(s): 274 - 281
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (628 KB)  

    In manufacturing CPT (Color Picture Tubes) used in TV sets and monitors, an ITC (Integrated Tube Components) adjustment process is involved. Automating the ITC adjustment process needs fast and robust visual sensing/measurement. Real time color purity and convergence measurement algorithms are described. Existing color purity measurement algorithms for ITC adjustment system often take too much time to detect color purity. Moreover, for convergence measurement, measurable data is not sufficient for accurate detection. To overcome these difficulties, real time vision system with 9 area cameras and many linear array cameras is developed. Area cameras are used for color purity measurements and linear array cameras are used for convergence measurements. To devise the purity measurement algorithm, the characteristics of CPT microscopic images are analyzed. To measure the exact color purity, several methods are selectively applied for calculating color purity depending on the conditions of CPT screen. For convergence measurement, special test CPT with no shadow mask and no black matrix is manufactured and a new measurement algorithm is developed using fuzzy inference and a priori knowledge taken from the specially manufactured CPT. The proposed algorithms are successfully applied as described in the experimental results View full abstract»

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  • Voice-bandwidth visual communication through logmaps: the Telecortex

    Publication Year: 1992 , Page(s): 4 - 10
    Cited by:  Papers (1)
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    Presents a robotic video telephone application of the Cortex-1 miniaturized space-variant active vision system. The embedded processor architecture of Cortex-1 enables it to implement a variety of functions not found in conventional video telephones, for example the camera tracks moving users with its pantilt mechanism. The authors also report an analog channel coding scheme to transmit logmap video images through band-limited analog channels such as the public switched telephone network (PSTN). The transmitter divides the frequency band into 768 channels, and modulates two values in quadrature on each channel. Some channels are reserved for special calibration signals enabling the receiver to recover both the phase and magnitude of the transmitted signal. The remaining channels carry pixel intensities View full abstract»

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  • Fiber identification in microscopy by ridge detection and grouping

    Publication Year: 1992 , Page(s): 205 - 212
    Cited by:  Papers (2)  |  Patents (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (968 KB)  

    In microscopy, a common task is the identification of individual objects having some particular shape, after which various features can be measured and feature statistics taken over the set of objects. The identification process can be automated by applying appropriate computer vision techniques. The author addresses the specific problem of fiber identification. Fibers appear as thin lines or curves in an image. In a 3D graph or `surface plot' of the image, they would appear as ridges or valleys. The paper describes a method of finding fibers based on the detection of individual ridge `edgels'; grouping of these edgels into simple, generally non-overlapping, curves; and the further grouping of curves into extended fibers View full abstract»

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  • Adaptive control techniques for dynamic visual repositioning of hand-eye robotic systems

    Publication Year: 1992 , Page(s): 110 - 117
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    Using active monocular vision for 3-D visual control tasks is difficult since the translational and the rotational degrees of freedom are strongly coupled. The paper addresses several issues in 3-D visual control and presents adaptive control schemes for the problem of robotic visual servoing (eye-in-hand configuration) around a static rigid target. The objective is to move the image projections of several feature points of the static rigid target to some desired image positions. The inverse perspective transformation is assumed partially unknown. The adaptive controllers compensate for the servoing errors, the partially unknown camera parameters, and the computational delays which are introduced by the time-consuming vision algorithms. The authors present a stability analysis along with a study of the conditions that the feature points must satisfy in order for the problem to be solvable. Finally, several experimental results are presented to verify the validity and the efficacy of the proposed algorithms View full abstract»

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  • Point target detection in spatially varying clutter

    Publication Year: 1992 , Page(s): 232 - 239
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    The authors develop and analyze high-speed algorithms for the detection of point targets in infrared (IR) images with spatially varying clutter. Current target detection systems are effective in detecting bright targets in a uniform sky, but in areas of strong clutter are either unable to detect targets reliably or are limited by high false alarm rates. The authors assume that target and sensor models are available. Clutter is considered to be poorly characterized and spatially varying. Target detection algorithms are based on filtering to enhance the target signal relative to the background, followed by an adaptive threshold. Statistical analysis of the algorithms is provided to quantify algorithm performance. The system implements a spatially adaptive algorithm that maximizes probability of target detection while maintaining a fixed false alarm rate. The algorithms are robust in the presence of spatially varying clutter. The authors include experimental results to illustrate this View full abstract»

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  • Algorithms for a fast confocal optical inspection system

    Publication Year: 1992 , Page(s): 298 - 305
    Cited by:  Papers (1)
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    Confocal imaging is an emerging technique for the measurement of surface topography in inspection. The authors present a system designed for fast acquisition and processing of confocal images, which consists of an optical front end using tilted confocal scanning, and an image processing module. The function of the image processing module is to improve signal resolution, perform smoothing and detect surfaces in the incoming signal. The input signal is first deconvolved in order to improve the depth resolution, and then processed to identify significant peaks. These peaks represent the position of different surfaces in the object being inspected. These peak locations are smoothed using a cluster based smoothing scheme to combat noise. For semi-transparent materials, the authors system is capable of detecting up to two surfaces at a given location View full abstract»

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  • System-level design of specialized VLSI hardware for computing relative orientation

    Publication Year: 1992 , Page(s): 128 - 135
    Cited by:  Papers (1)
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    Determining the relative orientation between the coordinate systems of two cameras is central to binocular stereo, as well as to the long range motion vision. The author proposes a system-level design for specialized hardware to compute relative orientation in real-time. The problem is difficult for two reasons: one is the nonlinearity of the equations which must be solved, and which may possess multiple solutions or local minima; the other is the difficulty of finding point correspondences. The major contribution of the paper is the theoretical analysis and simulation of simple methods, which map well to analog and digital hardware, for resolving both difficulties View full abstract»

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