Flexible extrinsic calibration of non-overlapping cameras using a planar mirror: Application to vision-based robotics

Multi-camera systems are used in many domains such as vision-based robotics or video surveillance. An accurate extrinsic calibration is usually required. In most of cases, this task is done by matching features through different views of the same scene. However, if the cameras´ fields of view do not overlap, such a matching procedure is not feasible anymore. Despite this constraint, this article deals with a simple and flexible extrinsic calibration method. The main contribution is the use of an unknown geometry scene and a planar mirror to create an overlap between views of the different cameras. Furthermore, the impact of the mirror refraction is also studied. The aim is the calibration of two non-overlapping cameras embedded on a vehicle, for visual navigation purpose in urban environment. The proposed approaches have been validated with both synthetic and real data in a metrological experimental framework.