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This paper details a method of detecting collision risks for Unmanned Aircraft during taxiing. Using images captured from an on-board camera, semantic segmentation can be used to identify surface types and detect potential collisions. A review of classifier lead segmentation concludes that texture feature descriptors lack the pixel level accuracy required for collision avoidance. Instead, segmentation...
In this paper, we develop a vision based formation control of quad-rotor UAVs using a monocular camera. A Lyapunov based approach is used to derive the controller. The objective of the controller for the follower UAV is to keep the leader vehicle at a desired bearing angle in its field-of-view. Also a desired fixed distance is maintained by using the size of the UAV as seen the image plane of the...
In this work, a vision-based Flight Guidance and Navigation System is developed for providing cross-country soaring functionality to a small UAV glider. The overall system is based on existing major contributions to autonomous soaring while still missing components have been designed. A cumulus-cloud mapping algorithm was extended to not only estimate the position of cumuli but also their drift velocity...
In this article, we proposed a framework to realize vision based multi-UAV cooperative mapping and control with image based visual servoing (IBVS). Equipped with a camera on each UAV platform respecitively, the multi-UAV system with overlapping camera field of view (FOV) can achieve ground mapping and formation cooperatively by image information interaction. Initially, we introduce the Multi-UAV system...
This paper presents an original approach for autonomous navigation based on RGB-D data and known 3D markers, where the basic concept is to detect and recognize the markers and then to use them for a straightforward pose estimation solution. The developed algorithms can allow a quadrotor to autonomously fly in (cooperative) GPS denied environments and/or when there is no natural or artificial illumination...
This work proposes an obstacle avoidance strategy for UAV navigation in indoor environments. The proposal is able to compute the distance among the UAV and the obstacles (which change their position dynamically), and then to select the closest one. When a collision risk is pointed out, the algorithm establish some escape points, whose orientation is aligned tangentially to the obstacle edge or to...
A monocular vision-based approach to indoor autonomous navigation for an off-the-shelf, low-cost Micro Air Vehicle (MAV) quadcopter is presented. Our approach is fully automated and relies on the extraction and analysis of the visual contours of the surrounding physical environment to successfully steer the MAV in hallways and to turn at intersections. All image analysis and processing necessary for...
The design and development of an autonomous camera platform for skydiving is presented. The device was designed to be compact, lightweight, and aerodynamically stable. Behavior of the device under a nominal wind speed at varying angles of attack, was obtained through Computational Fluid Dynamics analysis (CFD). A prototype was constructed for the purpose of verifying the CFD and simulation models...
In this paper, we present a decentralized cooperative multiple target tracking method for multiple Unmanned Aerial Vehicles (UAVs). The decentralized cooperative multi-target tracking algorithm incorporates an optimal sensor management scheme and a cooperative path planner. To localize and track targets, a set of Extended Kalman Filters (EKFs) is used onboard each UAV and resulting target estimates...
We present an approach for the automatic visual detection and position estimation of an air-to-air refueling drogue for unmanned aircraft. The drogue, which is dragged by an ahead flying tanker, is recorded by a passive color camera.
This paper discusses the design and implementation of a light-weight thermal camera payload for small fixed-wing UAVs with a pan/tilt mechanism and georeferencing based on a simple autopilot's GPS and IMU. Further, an effective and simple method to accurately calibrate a thermal camera is developed and tested. In order to evaluate the accuracy of the georeferencing algorithm, a test flight was conducted...
Aerial images with high spatial resolution and high temporal resolution were used to detect water stress based on canopy level normalized difference vegetation index (NDVI). We attempted to determine the correlation between stem water potential (SWP) and canopy NDVI with and without shade. Results indicated that removing the shade from the canopy improved the correlation between the NDVI of canopy...
Sense and Avoid (SAA) has been identified as one of the crucial technologies for integrating UAV into civil airspace, and vision based SAA is regarded as a promising solution. In this paper we described our vision based SAA system consisted of onboard vision detection system and Groud Control Station (GCS) to fulfill the intruder detection and avoid maneuver control tasks. To realize the small intruder...
Detect and Avoid (DAA) technology is widely acknowledged as a critical enabler for unsegregated Remote Piloted Aircraft (RPA) operations, particularly Beyond Visual Line of Sight (BVLOS). Image-based DAA, in the visible spectrum, is a promising technological option for addressing the challenges DAA presents. Two impediments to progress for this approach are the scarcity of available video footage...
In this paper a novel algorithm for distant aircraft detection for visual sense-and-avoid for UAV is presented. The algorithm uses local edge density to partition the frame into two types of regions. The first type is the unstructured or homogeneous part like sky region and the second part where there is a structured background, like high contrast clouds or terrain regions. The airplanes are detected...
This paper presents a novel solution for a typical small-scaled quad-rotor UAV to autonomously search for and land on a pre-designed marker placed on a rooftop and to observe a digit panel on the opposite building. The UAV is equipped with a downward-facing monocular camera for landing target detection and pose estimation, as well as a front-facing camera for digit panel observation and surveillance...
Consider the two characteristics: (1) Simultaneous localization and mapping (SLAM) is a popular algorithm for autonomous underwater vehicle, but visual SLAM is significantly influenced by weak illumination. (2)Geomagnetism-aided navigation and gravity-aided navigation are equally important methods in the field of vehicle navigation, but both are affected heavily by time-varying noises and terrain...
Precise trajectory tracking control for a quadcopter aerial vehicle using only a monocular camera and inertial sensing for localization is introduced in this work. Two different control laws based on linear behavior are proposed to follow desired trajectories. The algorithms are validated in real-time in the low-cost Parrot AR.Drone vehicle. Time-scale separation of the traslational and rotational...
This paper provides experimental validation of a uniformly semi-globally exponentially stable (USGES) non-linear observer for estimation of attitude, gyro bias, position, velocity and acceleration of a fixed-wing Unmanned Aerial Vehicle (UAV). The available sensors are an Inertial Measurement Unit (IMU), a Global Positioning System (GPS) receiver, a video camera, and an inclinometer. The UAV is flown...
This paper describes the design of model predictive control (MPC) for an unmanned aerial vehicle (UAV) used to track objects of interest identified by a real-time camera vision (CV) module in a search and track (SAT) autonomous system. A fully functional UAV payload is introduced, which includes an infra-red (IR) camera installed in a two-axis gimbal system. Hardware-in-loop (HIL) simulations are...
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