614 research outputs found

    Design considerations for a marker-free visual-based interfacing device for telco operation

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    Abstract: The parts of the system in the telecommunication environment that is used by technicians are sometimes completely menu driven. The interfaces to these parts can be made much simpler. Visual-based interfacing is a relatively new field of interest with advancements being made toward marker free human input tracking..

    A Marker-free Visual Based Interfacing Device for Menu Driven Systems

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    In this paper we propose a marker-free visual based interface device to be used with menu driven systems. This system, called HandsFree, uses the Graphics Processing Unit (GPU) together with Shader technology to perform the image processing..

    Image Processing on the GPU: Implementing the Canny Edge Detection Algorithm

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    Abstract: In this paper we present a detailed Graphics Processing Unit (GPU)-based implementation of the well known Canny edge detection algorithm. The aim of the paper is to provide an overview on our approach to implement the Canny edge detection algorithm, as it encompasses a set of image processing techniques. The result is an algorithm that can be applied in real-time applications..

    Mean shift object tracking with occlusion handling

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    An object tracking algorithm using the Mean Shift framework is presented which is largely invariant to both partial and full occlusions, complex backgrounds and change in scale. Multiple features are used to gain a descriptive representation of the target object. Image moments are used to determine the scale of the target object. A kalman filter is used to successfully track the target object through partial and full occlusions, the Bhattacharyya coefficient is used to determine the measurement noise estimation

    Automated surveillance and detection of foreign stationary objects

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    Abstract: CCTV systems are frequently monitored manually by a human observer. This human observer is typically responsible for dealing with tens or hundreds of cameras at a time. Potential security threats may easily be missed by the system’s human operators due to fatigue or being overwhelmed by the amount of change in the images..

    Stationary region predictor using a stationary camera

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    A method to determine the stationery probability of regions or feature points in a video sequence is proposed in this paper. This is done by identifying feature points using the Harris corner detector, finding descriptors for the feature points and then tracking the feature points. The information gained from tracking the feature points is then used to determine the stationery probability of these features. This method is shown to successfully identify probable stationery and moving regions in video sequences

    Image colourisation for compression using GPU hardware

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    Abstract: There is a growing demand for high definition (HD) graphics with multimedia content. This demand requires significantly more computational power than before. The increased demand in video content will continue to grow, resulting in vast volumes of data continuously shifted across networks and the internet..

    The Recent Cholera Outbreak in the South Mrican Gold Mining Industry

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    A large-scale cholera surveillance programme was introduced in South Africa in November 1973 as a result of the progressive southward spread of cholera in Africa. Moore's technique for the isolation of Salmonella paratyphi was modified for cholera detection. The method proved to be very sensitive and it was possible to detect Vibrio cholerae in main sewer lines after its casual and transient introduction by an unidentified carrier. Transmission occurred in the acc!im<:tisation centre, probably through the drinking of water contaminated after it had been drawn from the tap. Faecal contamination of the environment was demonstrated, and V. cho/erae was isolated from the floor, onto which it had been disseminated from the perianal region by means of profuse perspiration. Perpetuation of cholera was probably aided by a faecally contaminated air-humidifying water reservoir, the water of which experimentally allows survival and multiplication of V. cholerae for a week and longer. Prophylactic treatment of selected high-risk groups of people was administered in the form of doxycycline, which appeared to result in rapid termination of the epidemic. Mass vaccination of all mine personnel (20 000) was carried out to reduce the incidence of clinical cholera and the bacterial load

    On the stability of black hole event horizons

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    In this work we study a {\it gedanken} experiment constructed in order to test the cosmic censorship hypothesis and the second law of black hole thermo-dynamics. Matter with a negative gravitating energy is imagined added to a near extremal U(1)U(1)-charged static black hole in Einstein-Maxwell theory. The dynamics of a similar process is studied and the thermo-dynamical properties of the resulting black hole structure is discussed. A new mechanism which stabilizes black hole event horizons is shown to operate in such processes.Comment: 16, grammatical errors corrected and two references adde

    Ultrarelativistic black hole in an external electromagnetic field and gravitational waves in the Melvin universe

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    We investigate the ultrarelativistic boost of a Schwarzschild black hole immersed in an external electromagnetic field, described by an exact solution of the Einstein-Maxwell equations found by Ernst (the ``Schwarzschild-Melvin'' metric). Following the classical method of Aichelburg and Sexl, the gravitational field generated by a black hole moving ``with the speed of light'' and the transformed electromagnetic field are determined. The corresponding exact solution describes an impulsive gravitational wave propagating in the static, cylindrically symmetric, electrovac universe of Melvin, and for a vanishing electromagnetic field it reduces to the well known Aichelburg-Sexl pp-wave. In the boosting process, the original Petrov type I of the Schwarzschild-Melvin solution simplifies to the type II on the impulse, and to the type D elsewhere. The geometry of the wave front is studied, in particular its non-constant Gauss curvature. In addition, a more general class of impulsive waves in the Melvin universe is constructed by means of a six-dimensional embedding formalism adapted to the background. A coordinate system is also presented in which all the impulsive metrics take a continuous form. Finally, it is shown that these solutions are a limiting case of a family of exact gravitational waves with an arbitrary profile. This family is identified with a solution previously found by Garfinkle and Melvin. We thus complement their analysis, in particular demonstrating that such spacetimes are of type II and belong to the Kundt class.Comment: 11 pages, REVTeX
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