title: Calibration of an outdoor distributed camera network with a 3D point cloud.
abstract: Outdoor camera networks are becoming ubiquitous in critical urban areas of the largest cities around the world. Although current applications of camera networks are mostly tailored to video surveillance, recent research projects are exploiting their use to aid robotic systems in people-assisting tasks. Such systems require precise calibration of the internal and external parameters of the distributed camera network. Despite the fact that camera calibration has been an extensively studied topic, the development of practical methods for user-assisted calibration that minimize user intervention time and maximize precision still pose significant challenges. These camera systems have non-overlapping fields of view, are subject to environmental stress, and are likely to suffer frequent recalibration. In this paper, we propose the use of a 3D map covering the area to support the calibration process and develop an automated method that allows quick and precise calibration of a large camera network. We present two cases of study of the proposed calibration method: one is the calibration of the Barcelona Robot Lab camera network, which also includes direct mappings (homographies) between image coordinates and world points in the ground plane (walking areas) to support person and robot detection and localization algorithms. The second case consist of improving the GPS positioning of geo-tagged images taken with a mobile device in the Facultat de Matemàtiques i Estadística (FME) patio at the Universitat Politècnica de Catalunya (UPC).
authors: Institut de Robòtica i Informàtica Industrial, CSIC-UPC, Llorens Artigas 4-6,Barcelona 08028, Spain. aortega@iri.upc.edu.
authors: Agustín
authors: A
authors: Ortega
authors: Institute for Systems and Robotics, Instituto Superior Técnico, Av. Rovisco Pais 1, Lisbon 1049-001, Portugal. manuel.silva.thesis@gmail.com.
authors: Manuel
authors: M
authors: Silva
authors: Institut de Robòtica i Informàtica Industrial, CSIC-UPC, Llorens Artigas 4-6,Barcelona 08028, Spain. ehomar@iri.upc.edu.
authors: Ernesto H
authors: EH
authors: Teniente
authors: Institute for Systems and Robotics, Instituto Superior Técnico, Av. Rovisco Pais 1, Lisbon 1049-001, Portugal. ricardo@isr.ist.utl.pt.
authors: Ricardo
authors: R
authors: Ferreira
authors: Institute for Systems and Robotics, Instituto Superior Técnico, Av. Rovisco Pais 1, Lisbon 1049-001, Portugal. alex@isr.ist.utl.pt.
authors: Alexandre
authors: A
authors: Bernardino
authors: Institute for Systems and Robotics, Instituto Superior Técnico, Av. Rovisco Pais 1, Lisbon 1049-001, Portugal. jag@isr.ist.utl.pt.
authors: José
authors: J
authors: Gaspar
authors: Institut de Robòtica i Informàtica Industrial, CSIC-UPC, Llorens Artigas 4-6,Barcelona 08028, Spain. ehomar@iri.upc.edu.
authors: Juan
authors: J
authors: Andrade-Cetto
mesh_terms: D000465:Algorithms; D001185:Artificial Intelligence; D002138:Calibration; D007090:Image Interpretation, Computer-Assisted / Q000295:instrumentation* / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000295:instrumentation* / Q000379:methods*; D010363:Pattern Recognition, Automated / Q000379:methods*