Orientation Tracking for Outdoor Augmented Reality Registration

The biggest single obstacle to building effective augmented reality (AR) systems is the lack of accurate wide-area sensors for tracking the locations and orientations of objects in an environment. Active (sensor-emitter) tracking technologies require powered-device installation, limiting their use to prepared areas that are relatively free of natural or man-made interference sources. Vision-based systems can use passive landmarks, but they are more computationally demanding and often exhibit erroneous behavior due to occlusion or numerical instability. Inertial sensors are completely passive, requiring no external devices or targets, however, their drift rates in portable strapdown configurations are too great for practical use. In this paper, we present a hybrid approach to orientation tracking that integrates inertial and vision-based sensing. We exploit the complementary nature of the two technologies to compensate for the weaknesses in each component. Analysis and experimental results demonstrate the effectiveness of this approach.