Friday, May 7, 2010

30m Reef Surveys using a Video Camera Array




The BREAM video camera array. Circular holes in the front allow internal video cameras to film fishes.

The BREAM team has been busy for the past couple of months designing and building a video camera array, or "drop-camera", to survey coral reefs that are too deep to survey by divers.
A view of the underside of the video array, showing the circular holes
for the video cameras to film through, and the rectangular holes forlights.
BREAM technician Robert Fisher is standing proudly in the background.

The camera array has 2 HD1080 video cameras (with associated pairs of 1500W lights and a pair of green lasers to provide scale in the resultant video) facing downward to film the corals, and an additional pair of HD cameras without lights to film fish. The array also has a lower resolution camera that is wired to the surface by a cable that provides live video that we can see while the array is deployed. This video allows us to keep the array at the correct depth in the water column and hopefully will allow us to avoid unexpected objects etc.

We have been field testing the camera array, and hope to use it to survey reefs at 30m starting next week!

The array was primarily built by BREAM technician Robert Fisher. Video cameras and associated equipment is mounted on a custom-built aluminum frame, which slides on rails into a large fiberglass faring (which is a recycled water-pressure tank). We put the frame in a round faring to minimize the likelihood that the array gets snagged on a rock or piece of abandoned fishing gear etc.
This is the aluminum inner frame onto which video cameras
(with lenses protected by blue tape in this photo) and
lights and lasers are
attached. The frame
slides into the grey faring securely mounted on rails.


Aluminum fins were attached to the sides and the array faring has a tail, like a fish, so that the array tracks properly in the water.

The array is attached to the boat by a rope that connects to the rail along the top of the faring. A separate cable which carries the live video data will also connect to the boat, but is not under tension.

We will survey 25 locations around the entire Bermuda platform, getting the first view of the health and abundance of the corals and fishes on this amazing and important marine habitat!

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