AERIAL land photographs are vital for hundreds of scientific,
commercial and military projects. Now similar panoramas of the
seafloor may be possible, thanks to a scanning laser system
described at a conference last week. Such images "would
radically change the way we now think about and work in the
submarine environment", Ian MacDonald, a geochemist at Texas A&M
University, told the Oceans 95 conference in San Diego. The
problem is that seawater scatters and absorbs visible light in
the same way as thick fog. So while bright lights show nearby
objects underwater, scattered light obscures anything lying more
than a few metres away, even in clear water. But MacDonald
described a scanning laser system developed by the engineering
company Westinghouse that can map the seabed through up to 25
metres of water. In an attempt to minimise interference from
scattered light, designers of conventional undersea cameras
separate the illuminating lamp ... To continue reading this
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