2,740 research outputs found

    Real-time automated road, lane and car detection for autonomous driving

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    In this paper, we discuss a vision based system for autonomous guidance of vehicles. An autonomous intelligent vehicle has to perform a number of functionalities. Segmentation of the road, determining the boundaries to drive in and recognizing the vehicles and obstacles around are the main tasks for vision guided vehicle navigation. In this article we propose a set of algorithms which lead to the solution of road and vehicle segmentation using data from a color camera. The algorithms described here combine gray value difference and texture analysis techniques to segment the road from the image, several geometric transformations and contour processing algorithms are used to segment lanes, and moving cars are extracted with the help of background modeling and estimation. The techniques developed have been tested in real road images and the results are presented

    On-board real-time pose estimation for UAVs using deformable visual contour registration

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    Presentado al ICRA 2014 celebrado en Hong Kong del 31 de mayo al 7 de junio.We present a real time algorithm for estimating the pose of non-planar objects on which we have placed a visual marker. It is designed to overcome the limitations of small aerial robots, such as slow CPUs, low image resolution and geometric distortions produced by wide angle lenses or viewpoint changes. The method initially registers the shape of a known marker to the contours extracted in an image. For this purpose, and in contrast to state-of-the art, we do not seek to match textured patches or points of interest. Instead, we optimize a geometric alignment cost computed directly from raw polygonal representations of the observed regions using very simple and efficient clipping algorithms. Further speed is achieved by performing the optimization in the polygon representation space, avoiding the need of 2D image processing operations. Deformation modes are easily included in the optimization scheme, allowing an accurate registration of different markers attached to curved surfaces using a single deformable prototype. Once this initial registration is solved, the object pose is retrieved using a standard PnP approach. As a result, the method achieves accurate object pose estimation in real-time, which is very important for interactive UAV tasks, for example for short distance surveillance or bar assembly. We present experiments where our method yields, at about 30Hz, an average error of less than 5mm in estimating the position of a 19×19mm marker placed at 0.7m of the camera.This work has been partially funded by the Spanish Ministry of Economy and Competitiveness under project TaskCoop DPI2010-17112, by the ERANet Chistera project ViSen PCIN-2013-047 and by the EU project ARCAS FP7-ICT-2011-28761. A. Ruiz is supported by FEDER funds under grant TIN2012-38341-C04-03.Peer Reviewe

    Invariant object recognition

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    Automatic visual recognition using parallel machines

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    Invariant features and quick matching algorithms are two major concerns in the area of automatic visual recognition. The former reduces the size of an established model database, and the latter shortens the computation time. This dissertation, will discussed both line invariants under perspective projection and parallel implementation of a dynamic programming technique for shape recognition. The feasibility of using parallel machines can be demonstrated through the dramatically reduced time complexity. In this dissertation, our algorithms are implemented on the AP1000 MIMD parallel machines. For processing an object with a features, the time complexity of the proposed parallel algorithm is O(n), while that of a uniprocessor is O(n2). The two applications, one for shape matching and the other for chain-code extraction, are used in order to demonstrate the usefulness of our methods. Invariants from four general lines under perspective projection are also discussed in here. In contrast to the approach which uses the epipolar geometry, we investigate the invariants under isotropy subgroups. Theoretically speaking, two independent invariants can be found for four general lines in 3D space. In practice, we show how to obtain these two invariants from the projective images of four general lines without the need of camera calibration. A projective invariant recognition system based on a hypothesis-generation-testing scheme is run on the hypercube parallel architecture. Object recognition is achieved by matching the scene projective invariants to the model projective invariants, called transfer. Then a hypothesis-generation-testing scheme is implemented on the hypercube parallel architecture
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