A variational approach to camera motion smoothing

[EN] In this paper we study a variational problem derived from a computer vision application: video camera calibration with smoothing constraint. By video camera calibration we meanto estimate the location, orientation and lens zoom-setting of the camera for each video frame taking into account image visible features. To simplify the problem we assume that the camera is mounted on a tripod, in such case, for each frame captured at time t , the calibration is provided by 3 parameters : (1) P(t) (PAN) which represents the tripod vertical axis rotation, (2) T(t) (TILT) which represents the tripod horizontal axis rotation and (3) Z(t) (CAMERA ZOOM) the camera lens zoom setting. The calibration function t -> u(t) = (P(t),T(t),Z(t)) is obtained as the minima of an energy function I[u] . In thIs paper we study the existence of minima of such energy function as well as the solutions of the associated Euler-Lagrange equations.

Model of vessels for the 3D reconstruction

[EN] In this paper, we present a vascular tree model made with synthetic materials and which allows us to obtain images to make a 3D reconstruction. In order to create this model, we have used PVC tubes of several diameters and lengths that will let us evaluate the accuracy of our 3D reconstruction. We have made the 3D reconstruction from a series of images that we have from our model and after we have calibrated the camera. In order to calibrate it we have used a corner detector. Also we have used Optical Flow techniques to follow the points through the images going and going back. Once we have the set of images where we have located a point, we have made the 3D reconstruction choosing by chance a couple of images and we have calculated the projection error. After several repetitions, we have found the best 3D location for the point.

Sobre algunos problemas reales en visión por ordenador que conducen a sistemas de ecuaciones algebraicos

[EN] In this paper we present some real problems which appear in computer vision which yields to nonlinear system of algebraic equations. We study the problem of camera calibration. Roughly speaking camera calibration consists in looking at the camera position in the 3- D world using as information the projection of a 3- D Scene in a 2-D plane (the photogram). The problem is quite different when we use a single view or several views (stereo vision) of the 3-D scene. We will show in this paper how these problems yields to nonlinear algebraic system of equations.

3D reconstruction from a vascular tree model

[EN] In this paper, we present a vascular tree model made with synthetic materials and which allows us to obtain images to make a 3D reconstruction.We have used PVC tubes of several diameters and lengths that will let us evaluate the accuracy of our 3D reconstruction. In order to calibrate the camera we have used a corner detector. Also we have used Optical Flow techniques to follow the points through the images going and going back. We describe two general techniques to extract a sequence of corresponding points from multiple views of an object. The resulting sequence of points will be used later to reconstruct a set of 3D points representing the object surfaces on the scene. We have made the 3D reconstruction choosing by chance a couple of images and we have calculated the projection error. After several repetitions, we have found the best 3D location for the point.

Focal length calibration for depth recovery using a focusing technique

[EN]The work presented in this paper is related to Depth Recovery from Focus The approach starts calibrating focal length of the camera using the Gaussian lens law for the thin lens camera model Two approaches are presented based on the availability of the internal distance of the lens

Detección y evitación de objetos flotantes en el contexto de un vehículo autónomo de superficie

[ES]El Instituto Universitario de Sistemas Inteligentes y Aplicaciones Numéricas en Ingeniería y en especial la División de Robótica y Oceanografía Computacional está desarrollando un velero autónomo de superficie que requiere de un sistema para la detección y evasión de obstáculos. Dicho sistema se ha desarrollado sobre una Raspberry Pi con un servicio para la captura de imágenes, así como un servidor web que permita la modificación de la configuración de la cámara. Una vez completada dicha infraestructura se tomaron las fotografías que conformarán el conjunto de entrenamiento para el sistema de visión por computador y se desarrollará este último. Los resultados se han integrado con el sistema del control modificando el rumbo cuando se detecte un obstáculo.