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[ LAUNCH AND RECOVERY ] • [ WINCHES ] • [ SUB-SEA TOOLS & COMPONENTS ] [ SHIPBOARD A-FRAMES ] • [ AUV SYSTEMS ] • [ PRESSURE VESSELS ] • [ LASER TECHNOLOGY ] • [ OFFSHORE CONTAINERS ] LASER TECHNOLOGY 
Harbor Branch Engineering pioneered the use of underwater lasers to enhance imaging systems.
The small lasers used to help provide scale of objects within a video frame were first built
and installed on the HBOI JOHNSON-SEA-LINKs in 1984. The shutter system invented and patented by HBOI
gives the user a safe, visible indication of laser operation. Guest scientists using the JSL's soon recognized
the advantage of using these lasers, resulting in HBOI building lasers for use on the research
sub Alvin, MBARI's ROV's Ventana and Tiburon. The patented safety shutters are unique to the HBOI
units that sell for the same price as the competitor's units without the shutters. Lasers are available in
RED (640nm) and GREEN (532nm).
The new green laser operates at a wavelength of 532 nm, offering several
distinct advantages over red lasers in underwater applications. To the human eye a 532 nm green
laser will appear approximately
27 times brighter than a 670 nm red laser of equivalent power. Also, in sea water, the color
green has considerably less attenuation than the color red making it visible for greater distances.
For example, at a range of 20 meters, 44% of the light from a 532 nm green laser would remain as
compared to .002% from an equivalent power 640nm RED laser.
The lasers are typically used to provide scale within a video frame and/or still photography. Another function is to provide convergence to visually cue the optimum depth of field for a camera. We have also used the lasers as an aiming device for acoustic measuring systems, 3-D laser line scanners, and automated spearguns for grouper capture. Automated scaling of objects within a video can be performed with HBOI's laser scaling package. This package requires a minimum of three lasers (four is preferred), a computer with a frame capture board installed, and the HBOI software. A three beam laser quantitative measurement system has been developed for producing graphic overlays indicating range, area of coverage, scale, and other information on video images as they are displayed. In the simplest configuration, two parallel laser projections are aligned in a direction along the optical axis of a video camera. A third beam is oriented along an angle with respect to the parallel beams and is adjusted to be within the desired field of view at the maximum viewing distance. Laser reflections at a sufficient intensity to be clearly observable against the background are sensed by a video camera. These laser dots are automatically located, unless the user selects them manually, in the captured image and the desired dimensions are computed. In another configuration, three or more laser projections are arranged parallel to the video camera axis. For a fixed camera magnification, the parallel configuration establishes the location and tilt of a planar reflecting surface located at an arbitrary location in space. Additional laser projections improve the accuracy of the estimates and can be useful for obtaining the same information when a zoom lens is used with the video camera. Tests of these systems indicate that a ranging accuracy of better than 7 mm can be obtained at a two meter standoff distance. RED LASER SPECIFICATIONS
GREEN LASER SPECIFICATIONS
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• Green Laser Brochure - 192k download
