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In this paper we describe a flexible approach for determining the relative orientation of the camera with respect to the scene. The main premise of the approach is the fact that in man-made environments, the majority of lines is aligned with the principal orthogonal directions of the world coordinate frame. We exploit this observation towards efficient(More)
A digitally altered image, often leaving no visual clues of having been tampered with, can be indistinguishable from an authentic image. The tampering, however, may disturb some underlying statistical properties of the image. Under this assumption, we propose five techniques that quantify and detect statistical perturbations found in different forms of(More)
City environments often lack textured areas, contain repetitive structures, strong lighting changes and therefore are very difficult for standard 3D modeling pipelines. We present a novel unified framework for creating 3D city models which overcomes these difficulties by exploiting image segmentation cues as well as presence of dominant scene orientations(More)
This paper presents a nonparametric approach to semantic parsing using small patches and simple gradient, color and location features. We learn the relevance of individual feature channels at test time using a locally adaptive distance metric. To further improve the accuracy of the nonparametric approach, we examine the importance of the retrieval set used(More)
In this paper we study the problem of acquiring a topological model of indoors environment by means of visual sensing and subsequent localization given the model. The resulting model consists of a set of locations and neighborhood relationships between them. Each location in the model is represented by a collection of representative views and their(More)
Finding correspondences between two (widely) separated views is essential for several computer vision tasks, such as structure and motion estimation and object recognition. In the wide-baseline matching using scale and/or affine invariant features the search for correspondences typically proceeds in two stages. In the first stage a putative set of(More)
Visual servoing, i.e. the use of the vision sensor in feedback control, has been of increasing interest. Work has been done by applications in autonomous driving , manipulation, mobile robot navigation and surveillance. This paper studies the navigation task for a nonholonomic ground mobile base tracking an arbitrarily shaped ground curve using vision(More)
In this paper we present the results of a collaborative effort to design and implement a system for cooperative material handling by a small team of human and robotic agents in an unstructured indoor environment. Our approach makes fundamental use of human agents' expertise for aspects of task planning, task monitoring, and error recovery. Our system is(More)