An embedded calibration stereovision system

This paper describes an embedded calibration stereovision system that is able to be strongly online and auto-calibrated without placing a calibration device in front of the stereo camera, but with the device hidden inside the cavity of the system via a half-mirror. The stereo camera simultaneously observes a scene passing through the half-mirror and the calibration device reflected from the half-mirror, and makes the formation of an embedded calibration stereo pair containing both scene and the calibration device. The features of the calibration patterns are extracted from the embedded calibration stereo pair to estimate the stereo camera's parameters. We use a polyhedral-mirror to generate multiple virtual images of the calibration device to occupy large part of a scene image for accurate estimation. We also use several mirrors to extend the optical path from the calibration device to the stereo camera for depth recovery of distance objects. The system can be easily used in a wide range of applications without considering variation of camera parameters.