Pixel Club: Underwater Wide-Field Tomography of Sediment Resuspension

Speaker:
Adi Vainiger (EE, Technion)
Date:
Tuesday, 25.12.2018, 11:30
Place:
Room 337 Taub Bld.

Sediment resuspension is the transport of previously settled particles from the seafloor back into the overlying water. Measuring these abrupt and spatially varying events is challenging. Existing in-situ approaches are very localized. We presented a novel underwater wide field imaging system designed to (a) observe the seafloor and the water medium above it from a distance, (b) sense sediment resuspension events, and (c) algorithmically quantify the resuspension. Our technology quantifies the amount of material lifted, and its spatio-temporal distribution in (3D), using a computed tomography (CT) principle. We image resuspension plumes from multiple directions and locations. The suspended particles affect the radiation that reaches the cameras, hence the captured images. For easier data processing, during plume evolution, the plume is imaged against a diffuse backlight. By measuring radiance intensities during and prior to the resuspension, we extracted the optical depth on the line of sight per pixel. From the captured optical depths, we recover the extinction coefficient of the suspended sediment cloud in each voxel using the CT principle. The extinction coefficient is converted to resuspended density. *MSc. seminar under supervision of Prof. Yoav Shechner.

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