In order to improve usability and safety, modern unmanned aerial vehicles (UAVs) are equipped with sensors to monitor the environment, such as laser-scanners and cameras. One important aspect in this monitoring process is to detect obstacles in the flight path in order to avoid collisions. Since a large number of consumer UAVs suffer from tight weight and power constraints, our work focuses on obstacle avoidance based on a lightweight stereo camera setup. We use disparity maps, which are computed from the camera images, to locate obstacles and to automatically steer the UAV around them. For disparity map computation we optimize the well-known semi-global matching (SGM) approach for the deployment on an embedded FPGA. The disparity maps are then converted into simpler representations, the so called U-/V-Maps, which are used for obstacle detection. Obstacle avoidance is based on a reactive approach which finds the shortest path around the obstacles as soon as they have a critical distance to the UAV. One of the fundamental goals of our work was the reduction of development costs by closing the gap between application development and hardware optimization. Hence, we aimed at using high-level synthesis (HLS) for porting our algorithms, which are written in C/C++, to the embedded FPGA. We evaluated our implementation of the disparity estimation on the KITTI Stereo 2015 benchmark. The integrity of the overall realtime reactive obstacle avoidance algorithm has been evaluated by using Hardware-in-the-Loop testing in conjunction with two flight simulators.

Abstract-Many industrial domains rely on vision-based applications which require to comply with severe performance and embedded requirements. TULIPP will develop a reference platform, which consists of a hardware system, a tool chain and a real-time operating system. This platform defines implementation rules and interfaces to tackle power consumption issues while delivering high, energy efficient and guaranteed computing performance for image processing applications. Using this reference platform will enable designers to develop a complete solution at a reduced cost to meet the typical embedded systems requirements: Size, Weight and Power. Moreover, for less constrained systems which performance requirements cannot be fulfilled by one instance of the platform, the reference platform will also be scalable so that the resulting boards can be chained for higher processing power. The instance of the reference platform developed during the project will be use-case driven and split between the implementation of: a reference hardware architecture -a scalable low-power board; a low-power operating system and image processing libraries; a productivityenhancing tool chain. It will lead to three proof-of-concept demonstrators across different application domains: real-time and low-power medical image processing product prototype of surgical X-ray system (mobile c-arm); embedded image processing systems within Unmanned Aerial Vehicles (UAVs); automotive real time embedded systems for driver assistance. TULIPP will set up an ecosystem and will closely work with standardization organizations to propose new standards derived from its reference platform to the industry.

The paper describes an autonomous water vehicle (ASV) capable of autonomously mapping shallow water environments above and below the water surface. Over the past two years, Fraunhofer IOSB has developed a system that is fully electrified and equipped with extensive sensor technology (multibeam sonar, lidar, cameras, IMU, GNSS). For autonomous navigation, the complete processing pipeline was implemented, from obstacle detection and avoidance to trajectory planning and control to multi-sensor localization and mapping. Above water, both lidar-based mapping and photogrammetric methods are used; underwater, bathymetry data is obtained using sonar. The interface to the operator is realized by an interactive digital map table, which allows intuitive mission specification and evaluation.

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