Effective localization and tracking utilizing stereo vision for planetary micro-rover ROSA

Planetary exploration mainly depends on orbiters, rovers and landers. Especially the rovers provide a large covering area and close-up investigations about the planets. ROSA is a prototype tracked rover for the Mars exploration developed in the project sponsored by European Space Agency (ESA). The localization of ROSA is relied on stereo vision from the stereo cameras standing on top of the lander. However, due to the fixed position of the lander and the stereo cameras as well as the small field of view (FOV) of the cameras, the area where ROSA can be localized is very limited. Moreover, the stereo cameras are located too far to observe the geographical features in detail and to find out the interesting samples. In order to enlarge the localization area, a new system is designed and implemented: meanwhile it provides close-up observation of geographical features and takes images of the interesting samples. A pan-tilt unit (PTU) is installed to hold the bar of the stereo cameras. It can rotate around the pan and tilt axes to enable the cameras to cover larger areas. To ensure that the rover stays in the images of both cameras when the localization of rover is required and also that the cameras can autonomously follow the rover, a tracking method is implemented. It is related with the active marker, utilizing the background subtraction and blob connection to obtain the accurate LED position in the images, which helps to infer the rover position in the images. This tracking procedure is thoroughly consistent with the localization method. On the basis of the rover position in the images, the PTU is controlled to move the cameras to a proper orientation to ensure that the rover always appears in both images. A model for localization is built, which provides accurate localization information with less computation. Another camera is installed in the front panel of ROSA to take images and send them back to the ground. To control the mobility of ROSA in a correct and easy way, a new program with graphic user interface is developed for the ground station. Furthermore, a tracking program with video feedback has been developed.Validerat; 20101217 (root