34,712 research outputs found

    Cognitive visual tracking and camera control

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    Cognitive visual tracking is the process of observing and understanding the behaviour of a moving person. This paper presents an efficient solution to extract, in real-time, high-level information from an observed scene, and generate the most appropriate commands for a set of pan-tilt-zoom (PTZ) cameras in a surveillance scenario. Such a high-level feedback control loop, which is the main novelty of our work, will serve to reduce uncertainties in the observed scene and to maximize the amount of information extracted from it. It is implemented with a distributed camera system using SQL tables as virtual communication channels, and Situation Graph Trees for knowledge representation, inference and high-level camera control. A set of experiments in a surveillance scenario show the effectiveness of our approach and its potential for real applications of cognitive vision

    Efficient Constellation-Based Map-Merging for Semantic SLAM

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    Data association in SLAM is fundamentally challenging, and handling ambiguity well is crucial to achieve robust operation in real-world environments. When ambiguous measurements arise, conservatism often mandates that the measurement is discarded or a new landmark is initialized rather than risking an incorrect association. To address the inevitable `duplicate' landmarks that arise, we present an efficient map-merging framework to detect duplicate constellations of landmarks, providing a high-confidence loop-closure mechanism well-suited for object-level SLAM. This approach uses an incrementally-computable approximation of landmark uncertainty that only depends on local information in the SLAM graph, avoiding expensive recovery of the full system covariance matrix. This enables a search based on geometric consistency (GC) (rather than full joint compatibility (JC)) that inexpensively reduces the search space to a handful of `best' hypotheses. Furthermore, we reformulate the commonly-used interpretation tree to allow for more efficient integration of clique-based pairwise compatibility, accelerating the branch-and-bound max-cardinality search. Our method is demonstrated to match the performance of full JC methods at significantly-reduced computational cost, facilitating robust object-based loop-closure over large SLAM problems.Comment: Accepted to IEEE International Conference on Robotics and Automation (ICRA) 201

    The ruin and the circular narrative

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    The written component submitted to the University Research Degree Committee in fulfilment of the requirements for the degree of MASTERS BY RESEARCH in Fine ArtThis study constitutes the written component of a practice based Masters by Research in Fine Art. The research arises from my practice as an artist working in film and video in which I have come across links between the representation of ruins and aspects of narrative structure that have suggested the possibility that the ruin represents a nodal point in the work. Ruins have tended to be treated thematically by art historians and theorists and I will demonstrate that there are very few attempts to take the subject beyond the role of metaphor or allegory. However, Jacques Derrida has taken the idea of ruins into the idea of origin and it is this insight that lies at the core of this study. This leads to the idea of the ruin as a condensation of the end and beginning thereby giving it an important role in relation to narrative structure. The circular narrative is a form in which the end and beginning are stitched together at the same theoretical point as the ruin. In terms of practice the circular structure is explored in the form of film and video loops in which the circle structures the way the works physical production, its contextual background, its content and the ways in which it can be interpreted. Underlining this is Derrida's idea that the ruin is always already present at the origin of the work. These ideas are also combined with Freud's theory of the Death Instinct which is rooted in the compulsion to repeat. I have extended Peter Brooks' linking of the Death Instinct with linear narrative structure to include the circular narrative and tested this against my studio practice and the work of another artists, a writer and a film maker. In combining this link between the Death Instinct and the circular narrative with the ruin I have used the Freudian Theory of Primal Phantasies. This was also done to resolve the link with fantasy that was identified at the beginning of the project. My argument ends with the consolidation of these strands with Elisabeth Bronfen's use of the navel as a symbolic intervention into the conventional structures of psychoanalysis. In conclusion the identification of this nodal point in the structure of the work is shown to present an example of the ways in which theory and practice in contemporary art can be dynamically combined. In this way the art work is not only the result of the context from which it has emerged but also provides the means of interrogating that context

    Past, Present, and Future of Simultaneous Localization And Mapping: Towards the Robust-Perception Age

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    Simultaneous Localization and Mapping (SLAM)consists in the concurrent construction of a model of the environment (the map), and the estimation of the state of the robot moving within it. The SLAM community has made astonishing progress over the last 30 years, enabling large-scale real-world applications, and witnessing a steady transition of this technology to industry. We survey the current state of SLAM. We start by presenting what is now the de-facto standard formulation for SLAM. We then review related work, covering a broad set of topics including robustness and scalability in long-term mapping, metric and semantic representations for mapping, theoretical performance guarantees, active SLAM and exploration, and other new frontiers. This paper simultaneously serves as a position paper and tutorial to those who are users of SLAM. By looking at the published research with a critical eye, we delineate open challenges and new research issues, that still deserve careful scientific investigation. The paper also contains the authors' take on two questions that often animate discussions during robotics conferences: Do robots need SLAM? and Is SLAM solved
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