Measurements of the 3-D scour process around a pile in an oscillating flow through a stereo vision approach

Baglio, Salvatore; Faraci, Carla; Foti, Enrico; Musumeci, Rosaria Ester

doi:10.1016/s0263-2241(00)00064-6

Cited by 21 publications

(24 citation statements)

References 2 publications

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“…Stereophotography: Stereophotograpy is a type of photogrammetry that requires a minimum of two cameras to reconstruct a three-dimensional surface (Porter et al 2014). This technique has been used in a range of laboratory environments such as subaerial landslide surface reconstruction (McFall 2014;McFall et al 2018) but has more relevantly been used in laboratory studies to measure bathymetric changes around a pile (Faraci et al 2000;Baglio et al 2001;Porter et al 2014). Baglio et al 2001 used a laser and diffractive lens to create a grid of points on the sandy bottom, and the dynamic bathymetric measurements were taken using the changes in the spatial position of each point recorded on two cameras.…”

Section: Technology/methodologymentioning

confidence: 99%

“…This technique has been used in a range of laboratory environments such as subaerial landslide surface reconstruction (McFall 2014;McFall et al 2018) but has more relevantly been used in laboratory studies to measure bathymetric changes around a pile (Faraci et al 2000;Baglio et al 2001;Porter et al 2014). Baglio et al 2001 used a laser and diffractive lens to create a grid of points on the sandy bottom, and the dynamic bathymetric measurements were taken using the changes in the spatial position of each point recorded on two cameras. Their system did not account for the refraction of light through the air-glass-water interfaces, thus reducing the accuracy of their results (Porter et al 2014).…”

Section: Technology/methodologymentioning

confidence: 99%

“…Two different camera arrangements were used for the photogrammetric technique. One setup used a two-camera stereophotograpy setup similar to Baglio et al 2001, and the second setup used a single underwater camera. The photogrammetry was compared to the measurements of a 1 MHz altimeter with a beam footprint of 8 mm in diameter at the initial flat-bed surface.…”

Section: Technology/methodologymentioning

confidence: 99%

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Investigation into laboratory bathymetric measurement techniques

McFall¹,

Wolters²

2020

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There is no universally accepted way to accurately and efficiently measure bathymetry in laboratory hydraulic models. Remote sensing techniques can measure bathymetry without making contact with the model, and some remote sensing techniques can measure the bathymetry in laboratory models without draining the water. The four categories of remote sensing technology investigated in this report are echo sounding technology, laser technology, image processing technology, and radar technology. The technology of each category has strengths and limitations, but can be used in the laboratory to measure bathymetry. Echo sounding technology works well in environments with suspended sediment, but the accuracy is reduced by large beam footprints. Laser technology does not perform as well with suspended sediment but can provide high-accuracy bathymetric measurements. Stereophotography, discussed in the image processing technology section, requires optically clear water and can provide very accurate bathymetric mapping. Radar technology can be very helpful when sub-bottom stratigraphy is important. Technology from each of the categories has been scaled for field application to measure bathymetry and submerged coastal structures.

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Section: Technology/methodologymentioning

confidence: 99%

Section: Technology/methodologymentioning

confidence: 99%

Section: Technology/methodologymentioning

confidence: 99%

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Investigation into laboratory bathymetric measurement techniques

McFall¹,

Wolters²

2020

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“…Within the study of fluid motion, photogrammetry has been used for surface flow visualization (Karthikeyan and Venkatakrishnan 2011) and for measurements of the shape of free surface water waves (Rupnik et al 2015). The capability of photogrammetry to measure surfaces in a non-intrusive way makes it a good alternative to quantify changes in sediment beds in laboratory experiments (Baglio et al 2001;Peter Heng et al 2010;Rieke-Zapp and Nearing 2005;Stancanelli et al 2011;Stojic et al 1998).…”

Section: Introductionmentioning

confidence: 99%

“…However, measuring through the water interface is a common problem, which depends on the amplitude of the disturbances and on the distance from the measurement plane to the interface (as discussed by Akutina et al 2018, for particle tracking velocimetry measurements through a free surface ). Dynamic measurements were obtained by Baglio et al (2001) but did not account for distortions produced by the lens or effects due to refraction. A similar system was implemented in a study by Sumer et al (2012), where corrections for lens distortions were included but refraction was not modeled correctly.…”

Section: Introductionmentioning

confidence: 99%

High-resolution single-camera photogrammetry: incorporation of refraction at a fluid interface

et al. 2019

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Photogrammetry uses images of a three-dimensional structure to derive information about its shape and position. In this work, a photogrammetric technique is implemented with a single camera and a digital projector to measure changes in an underwater sediment bed. This implementation incorporates refraction at an interface allowing for measurements through a deformed or changing water surface. The digital projector provides flexibility in choosing projected patterns and has a high frame rate, which allows to easily increase the spatial and temporal resolution of the measurements. The technique requires first for both the camera and the projector to be calibrated using triangulation. With the calibration, we construct lines in three-dimensional space that originate from the projector and the camera, and intersect on the surface to be measured. To correctly incorporate refraction due to a change of medium, each line in space is recalculated from its intersection with the interface using Snell's law. This has the benefit that only one calibration for measurements is needed if the location and shape of the interface are known. The technique is validated by measuring a submerged undulated surface, plastic objects and a sediment bed. In particular, the undulated plate is reconstructed under a flat and a parabolic water surface. Finally, the technique is used in combination with particle image velocimetry to dynamically measure a changing sediment bed under an oscillating flow and the flow velocity at the free surface.

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Measuring Sandy Bottom Dynamics by Exploiting Depth from Stereo Video Sequences

Musumeci

Farinella

Foti

et al. 2013

Image Analysis and Processing – ICIAP 2013

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In this paper an imaging system for measuring sandy bottom dynamics is proposed. The system exploits stereo sequences and projected laser beams to build the 3D shape of the sandy bottom during time. The reconstruction is used by experts of the field to perform accurate measurements and analysis in the study of the final equilibrium conditions of sea bottoms in the presence of water flows. Results obtained by processing data acquired in hydraulic laboratory confirm the effectiveness of the system which makes simple and fast the understanding of the sandy bottom dynamics and the related equilibrium phenomena.

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Measurements of the 3-D scour process around a pile in an oscillating flow through a stereo vision approach

Cited by 21 publications

References 2 publications

Investigation into laboratory bathymetric measurement techniques

Investigation into laboratory bathymetric measurement techniques

High-resolution single-camera photogrammetry: incorporation of refraction at a fluid interface

Measuring Sandy Bottom Dynamics by Exploiting Depth from Stereo Video Sequences

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