Seite - 21 - in Proceedings of the OAGM&ARW Joint Workshop - Vision, Automation and Robotics

Estimated distance with VO in m 3. loop 2. loop 1. loop 0 500 1000 1500 2000 2500 3000 −100 −50 0 50 100 150 200 250 300 350 400 Fig. 9: Scenario 2 – Comparison of estimated yaw angles of the yaw angle like it‘s necessary for agricultural vehicles. Using the given laptop, in average the computing time of the pose estimation takes 0.349s per stereo pair. This equates to approximately three pose estimations per second. V. CONCLUSION AND FUTURE WORK We developed a Visual Odometry system that is based on a stereo-camera pair and capable of estimating the position and orientation of an agricultural vehicle in GPS-obstructed environments. We deployed our system on a small truck and carried out measurements for two different logging road scenarios. The results showthat an insufficientdistribution of features can lead to an ill-conditioned pose estimation, and hence to an inaccurately estimated distance and pitch angle. Due to the incremental concatenation of relative motions, this results in an increased error in position. However, our robust VO system is highly capable of estimating the orien- tation (yaw angle) with acceptable accuracy in unstructured environment. This is especially shown in the first scenario in the dense forest where the signal quality of GPS lacks. Future work includes the improvement of the distribu- tion of features and hence the pose estimation. Uniformly distributed features could be achieved via using different detector parameters for the upper and lower half of the image. Another goal is to reduce the computing time of the VO to facilitate an online system. This can mainly be done via the parallelization of repeatable tasks like feature detection and description. Furthermore, the next steps include the incorporation of the data of an IMU that were recorded simultaneously during our measurements. 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