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We propose a combined line segment and elliptical arc detector , which formally guarantees the control of the number of false positives and requires no parameter tuning. The accuracy of the detected elliptical features is improved by using a novel non-iterative ellipse fitting technique , which merges the algebraic distance with the gradient orientation.(More)
We investigate the projective properties of the feature consisting of two concentric circles. We demonstrate there exist geometric and algebraic constraints on its projection. We show how these constraints greatly simplify the recoveries of the affine and Euclidean structures of a 3D plane. As an application, we assess the performances of two camera(More)
The plane-based calibration consists in recovering the internal parameters of the camera from the views of a planar pattern with a known geometric structure. The existing direct algorithms use a problem formulation based on the properties of basis vectors. They minimize algebraic distances and may require a 'good' choice of system normalization. Our(More)
Plane-based calibration is now a very popular procedure because of its flexibility. One key step consists in detecting a set of coplanar features, from which the Euclidean structure of the corresponding 3D plane has to be computed. We suggest to use confocal conics as calibration targets, as they offer undeniable advantages over other ones (e.g., points or(More)
Les hypothèses simplificatrices usuelles du shape from shading , technique bien connue de reconstruction tridimen-sionnelle à partir d'une seule vue, amènent à le formuler sous une forme apparemment simple, qui est ((l'équation de l'eikonale)). La résolution de cette équation pose néan-moins de sérieuses difficultés, qui sont dues en grande par-tie à(More)
High-resolution panoramic video with a wide field-of-view is popular in many contexts. However, in many examples, like surveillance and sports, it is often desirable to zoom and pan into the generated video. A challenge in this respect is real-time support, but in this demo, we present an end-to-end real-time panorama system with interactive zoom and(More)
A C<sup>2</sup>Tag refers to a set of concentric circles of different radii. C<sup>2</sup>Tags have been recently introduced in computer vision, in particular for camera calibration, as they offer highly interesting photometric and geometric properties, compared to the classical &#x201C;checkerboard&#x201D; tags. In this work, we propose the general(More)
We present a new formulation to the well known problem of shape-from-texture from a single image by casting the task as a multi-plane based camera pose estimation problem. Our first contribution is methodological: we show that by using a piecewise affine model, instead of a perspective one, we can avoid the numerical instabilities in the estimation of the(More)