Lidar (light detection and ranging)

Killinger, Dennis K.

doi:10.1533/9780857098733.2.292

Cited by 11 publications

(5 citation statements)

References 25 publications

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“…Laser scanning, also known as LiDAR (Light Detection and Ranging) is an active tele-detection method which uses electromagnetic waves sent by the emitter. The result is point cloud with coordinates ( x, y, z ) ( Jaboyedoff et al, 2010 ; Killinger, 2014 ). The measuring system (LiDAR) consists mainly of a transmitter i.e., a module generating laser light (diodes), an optical telescope focusing the returning reflected radiation and a detector converting light energy into an impulse recorded in the module that records the acquired data.…”

Section: Methodsmentioning

confidence: 99%

“…It should also be noted that hydraulic instrumentation has advanced significantly, so fundamental flow parameters or river bed shape can be measured with greater precision. For instance, the PIV imaging anemometry system can be used to describe the distribution of velocity fields in the area of water structure and the description of a bottom shape can be perform using an echo sounder, e.g., fixed on a boat, or by laser scanning technique ( Hager & Boes, 2014 ; Killinger, 2014 ).…”

Section: Introductionmentioning

confidence: 99%

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On local scouring downstream small water structures

Kiraga

Popek

2020

PeerJ

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Background In order to regulate water flow, hydraulic structures such as weirs or checks, frequently equipped with gates, are used. Water can flow below or over the gate or, simultaneously, over and below the gate. Both diversifications of hydraulic gradient, being an effect of damming up a river by the structure and shear stresses at the bed, which exceeds the critical shear stress value, invoke the local scouring downstream the structure. This phenomenon has been studied in laboratory and field conditions for many years, however Researchers do not agree on the parameters that affect the size of the local scour and the intensity of its formation. There are no universal methods for estimating its magnitude However, solutions are sought in the form of calculation formulas typical for the method of flow through the structure, taking into account the parameters that characterize a given structure. These formulas are based on factors that affect the size of the local scours, that is, their dimensions and location. Examples of such formulas are those contained in this article: Franke (1960), Straube (1963), Tarajmovič (1966), Rossinski & Kuzmin (1969) equations. The need to study this phenomenon results from the prevalence of hydrotechnical structures equipped with gates (from small gated checks to large weirs) and from potential damage that may be associated with excessive development of local erosion downstream, including washing of foundations and, consequently, loss of stability of the structure. Methods This study verifies empirical formulas applied to estimate the geometry parameters of a scour hole on a laboratory model of a structure where water is conducted downstream the gate with bottom reinforcements of various roughness. A specially designed remote-controlled measuring device, equipped with laser scanner, was applied to determine the shape of the sandy bottom. Then the formula optimization is conducted, using Monte Carlo sampling method, followed by verification of field conditions. Results The suitability of a specially designed device, equipped with laser scanner for measuring the bottom shape in laboratory conditions was demonstrated. Simple formula describing local scour geometry in laboratory conditions was derived basing on the Straube formula. The optimized formula was verified in field conditions giving very good comparative results. Therefore, it can be applied in engineering and designing practices.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

On local scouring downstream small water structures

Kiraga

Popek

2020

PeerJ

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show abstract

Section: Methodsmentioning

confidence: 99%

“…For instance, the PIV imaging anemometry system can be used to describe the distribution of velocity fields in the area of water structure and the description of a bottom shape can be perform using an echo sounder, e.g. fixed on a boat, or by laser scanning technique (Hager & Boes 2014;Killinger 2014).…”

Section: Introductionmentioning

confidence: 99%

Peer Review #1 of "On local scouring downstream small water structures (v0.1)"

Szydłowski¹

2020

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“…LiDAR sensors use the ToF of reflected laser pulses to measure distances and detect objects [22]. A LiDAR camera emits billions of pulses per second up to 360 • in all directions, thus generating a 3D matrix for the surrounding environment.…”

Section: Lidar Sensorsmentioning

confidence: 99%

Sensing Technology Survey for Obstacle Detection in Vegetation

Lohar

Zhu

Young

et al. 2021

Future Transportation

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This study reviews obstacle detection technologies in vegetation for autonomous vehicles or robots. Autonomous vehicles used in agriculture and as lawn mowers face many environmental obstacles that are difficult to recognize for the vehicle sensor. This review provides information on choosing appropriate sensors to detect obstacles through vegetation, based on experiments carried out in different agricultural fields. The experimental setup from the literature consists of sensors placed in front of obstacles, including a thermal camera; red, green, blue (RGB) camera; 360° camera; light detection and ranging (LiDAR); and radar. These sensors were used either in combination or single-handedly on agricultural vehicles to detect objects hidden inside the agricultural field. The thermal camera successfully detected hidden objects, such as barrels, human mannequins, and humans, as did LiDAR in one experiment. The RGB camera and stereo camera were less efficient at detecting hidden objects compared with protruding objects. Radar detects hidden objects easily but lacks resolution. Hyperspectral sensing systems can identify and classify objects, but they consume a lot of storage. To obtain clearer and more robust data of hidden objects in vegetation and extreme weather conditions, further experiments should be performed for various climatic conditions combining active and passive sensors.

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Lidar (light detection and ranging)

Cited by 11 publications

References 25 publications

On local scouring downstream small water structures

On local scouring downstream small water structures

Peer Review #1 of "On local scouring downstream small water structures (v0.1)"

Sensing Technology Survey for Obstacle Detection in Vegetation

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