An integrated approach of flash flood analysis in ungauged Mediterranean watersheds using post‐flood surveys and unmanned aerial vehicles

Abstract. Unmanned aerial vehicles (UAVs) have the potential to capture information about the earth's surface in dangerous and previously inaccessible locations. Through image acquisition of flash flood events and subsequent object-based analysis, highly dynamic and oft-immeasurable hydraulic phenomena may be quantified at previously unattainable spatial and temporal resolutions. The potential for this approach to provide valuable information about the hydraulic conditions present during dynamic, high-energy flash floods has until now not been explored. In this paper we adopt a novel approach, utilizing the Kande–Lucas–Tomasi (KLT) algorithm to track features present on the water surface which are related to the free-surface velocity. Following the successful tracking of features, a method analogous to the vector correction method has enabled accurate geometric rectification of velocity vectors. Uncertainties associated with the rectification process induced by unsteady camera movements are subsequently explored. Geo-registration errors are relatively stable and occur as a result of persistent residual distortion effects following image correction. The apparent ground movement of immobile control points between measurement intervals ranges from 0.05 to 0.13 m. The application of this approach to assess the hydraulic conditions present in the Alyth Burn, Scotland, during a 1 : 200 year flash flood resulted in the generation of an average 4.2 at a rate of 508 measurements s−1. Analysis of these vectors provides a rare insight into the complexity of channel–overbank interactions during flash floods. The uncertainty attached to the calculated velocities is relatively low, with a spatial average across the area of ±0.15 m s−1. Little difference is observed in the uncertainty attached to out-of-bank velocities (±0.15 m s−1), and within-channel velocities (±0.16 m s−1), illustrating the consistency of the approach.

Download Full-text

DETECTION OF CITRUS TREES FROM UAV DSMS

ISPRS Annals of Photogrammetry Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-annals-iv-1-w1-27-2017 ◽

2017 ◽

Vol IV-1/W1 ◽

pp. 27-34 ◽

Cited By ~ 4

Author(s):

A. O. Ok ◽

A. Ozdarici-Ok

Keyword(s):

Unmanned Aerial Vehicles ◽

State Of The Art ◽

Integrated Approach ◽

Radial Symmetry ◽

Single Source ◽

Local Maxima ◽

Manual Intervention ◽

Aerial Vehicles ◽

Surface Models ◽

Citrus Trees

This paper presents an automated approach to detect citrus trees from digitals surface models (DSMs) as a single source. The DSMs in this study are generated from Unmanned Aerial Vehicles (UAVs), and the proposed approach first considers the symmetric nature of the citrus trees, and it computes the orientation-based radial symmetry in an efficient way. The approach also takes into account the local maxima (LM) information to verify the output of the radial symmetry. Our contributions in this study are twofold: (i) Such an integrated approach (symmetry + LM) has not been tested to detect (citrus) trees (in orchards), and (ii) the validity of such an integrated approach has not been experienced for an input, e.g. a single DSM. Experiments are performed on five test patches. The results reveal that our approach is capable of counting most of the citrus trees without manual intervention. Comparison to the state-of-the-art reveals that the proposed approach provides notable detection performance by providing the best balance between precision and recall measures.

Download Full-text

Development of thickened semi-synthetic engine oil M-5z / 20 AERO for four-stroke gasoline engines aircraft piston of unmanned aerial vehicles (UAVs)

World of OIL Products the Oil Companies Bulletin ◽

10.32758/2071-5951-2020-0-6-44-47 ◽

2020 ◽

Vol 06 ◽

pp. 44-47

Author(s):

A.A. Moykin ◽

◽

A.S. Medzhibovsky ◽

S.A. Kriushin ◽

M.V. Seleznev ◽

...

Keyword(s):

Unmanned Aerial Vehicles ◽

Engine Oil ◽

Motor Oil ◽

Gasoline Engines ◽

State Research Institute ◽

Technical Requirements ◽

Aerial Vehicles ◽

State Research ◽

Industrial Batch ◽

The Russian Federation

Nowadays, the creation of remotely-piloted aerial vehicles for various purposes is regarded as one of the most relevant and promising trends of aircraft development. FAU "25 State Research Institute of Chemmotology of the Ministry of Defense of the Russian Federation" have studied the operation features of aircraft piston engines and developed technical requirements for motor oil for piston four-stroke UAV engines, as well as a new engine oil M-5z/20 AERO in cooperation with NPP KVALITET, LLC. Based on the complex of qualification tests, the stated operational properties of the experimental-industrial batch of M-5z/20 AERO oil are generally confirmed.

Download Full-text