scholarly journals MEASUREMENT OF THE SPECTRAL REFLECTION COEFFICIENTS FOR SURFACES UNDER A MULTISPECTRAL AERIAL SURVEY BY DIGITAL CAMERA

2019 ◽  
Vol 8 ◽  
pp. 279-285
Author(s):  
Stanislav Arbuzov ◽  
Evgenij Gritskevich ◽  
Darja Michaylova ◽  
Anna Selezneva
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Digital Camera ◽  
Aerial Survey ◽  
Field Of View ◽  
Reflection Coefficients ◽  
Digital Cameras ◽  
Agricultural Lands ◽  
Instrument Making ◽  
Spectral Reflection ◽  
Aerial Vehicles

Monitoring of the environment with the help of unmanned aerial vehicles is currently one of the most developing branches of optoelectronic instrument-making. Digital cameras installed on these devices make it possible to survey the underlying surface in order to select the its features. The use of unmanned aerial vehicles for the control of agricultural lands is a very perspective case of such monitoring. The technique of measuring the spectral reflection coefficients of surfaces is developed for identification of the vegetation state observed in the field of view of multispectral digital camera. The method allows determining the spectral reflectance of the calibration surfaces using the reference ones and after that to find the parameters of working surfaces using the calibration ones. The obtained results are applied under the analysis and processing of images obtained in the course of the unmanned aviation system that monitors agricultural lands.

scholarly journals Small Obstacle Avoidance Sensor

2013 ◽  
Vol 2013 ◽  
pp. 1-6
Author(s):  
Richard H. Vollmerhausen
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Laser Wavelength ◽  
Night Vision ◽  
Field Of View ◽  
Laser Ranging ◽  
Aerial Vehicles ◽  
Package Size ◽  
Charge Coupled Devices ◽  
Emitter Array ◽  
Small Obstacle

This paper describes a laser ranging sensor that is suitable for applications like small unmanned aerial vehicles. The hardware consists of a diode emitter array and line-scan charge coupled devices. A structured-light technique measures ranges up to 30 meters for 64 field angles in a 90 degree field of view. Operation is eye safe, and the laser wavelength is not visible to night vision goggles. This paper describes a specific sensor design in order to illustrate performance for a given package size.

scholarly journals Behaviour reactions of bottlenose dolphins (Tursiops truncatus) to multirotor Unmanned Aerial Vehicles (UAVs)

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ticiana Fettermann ◽  
Lorenzo Fiori ◽  
Martin Bader ◽  
Ashray Doshi ◽  
Dan Breen ◽  
...  
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Tursiops Truncatus ◽  
Bottlenose Dolphins ◽  
Cost Effective ◽  
Aerial Survey ◽  
Cetacean Species ◽  
Age Class ◽  
Aerial Vehicles ◽  
Vtol Uav ◽  
Aerial Observation

Abstract Unmanned aerial vehicles (UAVs) represent a novel and cost effective research tool to investigate cetacean behaviour, as conventional aircraft are expensive, limited in the altitude they can fly at and potentially disturb sensitive wildlife. In addition, the aerial observation from the UAVs allows assessment of cetacean behaviour from an advantageous perspective and can collect high spatial and temporal resolution data, providing the opportunity to gather accurate data about group size, age class and subsurface behaviour. However, concerns have been raised about the potential risks of disturbance to animals caused by the UAV’s visual and acoustic stimuli. Boat-based surveys were conducted to assess the short-term behavioural responses of resting bottlenose dolphins (Tursiops truncatus) to a lightweight Vertical take-off and landing (VTOL) UAV flown at 10, 25, and 40 m altitude. Changes in group swim direction and frequencies of surface and aerial behavioural events were recorded from an anchored research vessel before (control) and during the aerial survey. The number of reorientation and tail slap events increased significantly between controls and flights when the UAV was flown at 10 m over the animals. In contrast, no significant differences were detected when the aircraft was flown at 25 and 40 m altitude. However, a precautionary approach is recommended for research applications requiring lower flight altitudes, with further research recommended to assess how different cetacean species and age class may respond to the UAV presence.

Three-dimensional image coordinate-based missing region of interest area detection and damage localization for bridge visual inspection using unmanned aerial vehicles

2020 ◽  
pp. 147592172091867
Author(s):  
Sungsik Yoon ◽  
Gi-Hun Gwon ◽  
Jin-Hwan Lee ◽  
Hyung-Jo Jung
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Visual Inspection ◽  
Experimental Validation ◽  
Three Dimensional ◽  
Region Of Interest ◽  
Field Of View ◽  
Damage Localization ◽  
Distance Information ◽  
Dimensional Image ◽  
Aerial Vehicles

In this study, the three-phase missing region of interest area detection and damage localization methodology based on three-dimensional image coordinates was proposed. In Phase 1, the coordinate transformation is performed by the position and attitude information of the unmanned aerial vehicles and camera, and the coordinates of the center point of each acquired image are obtained with the distance information between the camera and the target surface. For Phase 2, the size of the field of view of every acquired image is calculated using the focal length and working distance of the camera. Finally, in Phase 3, the missing part of the region of interest area can be identified and any damage detected at the individual image level can also be localized on the whole inspection region using information about the sizes of the field of view in all images calculated in the previous phase. In order to demonstrate the proposed methodology, experimental validation was performed on the actual bridge pier and deck as well as the lab-scale concrete shear wall. In the tests, the missing area detection and damage localization results were compared with image stitching and human visual inspection results, respectively. Experimental validation results have shown that the proposed methodology identifies missing areas and damage locations within reasonable accuracy of 10 cm.

scholarly journals Computationaly Simple Obstacle Avoidance Control Law for Small Unmanned Aerial Vehicles

2015 ◽  
Vol 9 (1) ◽  
pp. 50-56 ◽  
Author(s):  
Jakub Cieśluk ◽  
Zdzisław Gosiewski ◽  
Leszek Ambroziak ◽  
Sławomir Romaniuk
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Obstacle Avoidance ◽  
Imaging System ◽  
Information Source ◽  
Digital Camera ◽  
Control Law ◽  
Simulation Studies ◽  
Aerial Vehicles ◽  
Avoidance Control ◽  
Computational Simplicity

Abstract The investigations of the system which allow to avoid obstacles by the unmanned aerial vehicles (UAV) are presented in the paper. The system is designed to enable the full autonomous UAV flight in an unknown environment. As an information source about obstacles digital camera was used. Developed algorithm uses the existing relations between the imaging system and the parameters read from the UAV autopilot. Synthesis of the proposed obstacle avoidance control law was oriented for computational simplicity. Presented algorithm was checked during simulation studies and in-flight tests.

scholarly journals COMPARISON OF UAV LIDAR ODOMETRY OF ROTATING AND FIXED VELODYNE PLATFORMS

2020 ◽  
Vol XLIII-B1-2020 ◽  
pp. 527-534
Author(s):  
M. L. Tazir ◽  
N. Seube
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Three Dimensional ◽  
High Accuracy ◽  
Field Of View ◽  
Direct Access ◽  
Refresh Rate ◽  
Additional Degree ◽  
Aerial Vehicles ◽  
3D Information ◽  
Axis Passing

Abstract. Three-dimensional LiDAR rangefinders are increasingly integrated into unmanned aerial vehicles (UAV), due to their direct access to 3D information, their high accuracy and high refresh rate, and their tendency to be lightweight and cheaper. However, all commercial LiDARs can only offer a limited vertical resolution. To cope with this problem, a solution can be to rotate the LiDAR on an axis passing through its center, adding an additional degree of freedom and allowing more overlap, which significantly enlarges the sensor scope and allows having a complete spherical field of view (FOV). In this paper, we explore this solution in detail for drone’s context, while making comparisons between the rotating and fixed configurations for a Multi-Layers LiDAR (MLL) of type Velodyne Puck Lite. We investigate its impact on the LiDAR Odometry (LO) process by comparing the resulting trajectories with the data of the two configurations, as well as, qualitative comparisons, of the resulting maps.

scholarly journals FIRST APPROACH TO UAV-BASED CONTACT INSPECTION: A SMART PAYLOAD FOR NAVIGATION IN THE NEIGHBOURHOOD OF STRUCTURES

2019 ◽  
Vol XLII-2/W13 ◽  
pp. 323-328 ◽  
Author(s):  
L. M. González-de Santos ◽  
J. Martínez-Sánchez ◽  
H. González-Jorge ◽  
A. Novo ◽  
P. Arias
Keyword(s):  
Remote Sensing ◽  
Unmanned Aerial Vehicles ◽  
Calibration Curve ◽  
Horizontal Plane ◽  
Indoor Environment ◽  
Digital Cameras ◽  
Good Position ◽  
Aerial Vehicles ◽  
Close Range ◽  
Inspection Tasks

<p><strong>Abstract.</strong> Many inspection tasks of structures are already carried out by unmanned aerial vehicles (UAV). Most of these inspections consist of using payloads for close range remote sensing purposes (i.e. digital cameras, thermal or LiDAR sensors). In all these inspection tasks the UAV system does not need to be close to the structure and typically the GPS coverage is good to perform mission navigation. In this paper, a smart payload developed for navigation in the neighbourhood of structures is presented. With this payload the UAV system is able to control the distance to a structure and the angle formed by the UAV and the structure in the horizontal plane. This payload has been calibrated in order to determine the calibration curve and measure the accuracy of the payload. The system has been tested in an indoor environment (GPS-denied). Good position and angular results has been obtained.</p>

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