| Description |
In situ seafloor images were acquired at four sites (SKM, SLG, LDB, WLW) in the lower Columbia River, Washington and Oregon, with an underwater camera system between June 5 and June 8, 2021. Between 248 and 427 digital images of the sediment surface were collected at each site with an underwater camera system that was repeatedly lowered to the seabed along a series of 1 km-long transects oriented along the main navigation channel and spaced about 60 m apart. The camera consisted of a FLIR Blackfly BFS-PGE-50S5 camera and 50 mm lens in a waterproof housing that resulted in a field of view of approximately 17 mm and a resolution of 0.00657 mm per pixel when the housing window was flush with the sediment surface. The imagery is provided in .tif format and compressed into .zip archives for each site. Images used for calibration of the automated processing algorithm to determine sediment grain size distributions were different than those used to validate the technique and were provided in separate .zip archives. [More]
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