Grain Size from Digital Images of Sediment

Grain-size hardware

We have fabricated nearly a dozen different instruments for in-situ measurement of bed sediment under water and in air (Rubin and others, 2007; Warrick and others, 2009; Rubin and others, in press). All of the underwater systems all use a video camera or digital camera in an air-filled housing that rests on the bed. By eliminating an optical path through the water, high-quality images can be obtained even in turbid water.

By eliminating an optical path through the water, high-quality images can be obtained even in turbid water (Rubin and others, 2007).

This hand-held digital still camera is used on beaches, and underwater by divers (Rubin and others, 2007).

Hand-held camera is being used on a sand bar in Grand Canyon (Rubin and others, 2007).

Hand-held wireless camera is linked to a tablet computer, and collects images and calculate grain size in real time in the field.

A video camera in the wrecking ball photographs bed sediment in Grand Canyon (Rubin and others, 2007).

A tripod-mounted camera photographs bed sediment ranging in size from sand to boulders (Warrick and others, 2009).

This automated system collects bed-sediment images of the seafloor from a remote tripod using a 5-megapixel gigabit Ethernet video camera. Tripod has a hydraulically activated arm that lowers the video camera to the bed at pre-set intervals. Camera housing (top left end of arm) is 30 cm long.