Classic Computer Magazine Archive COMPUTE! ISSUE 127 / MARCH 1991 / PAGE 46

Shipwreck. (search for the ironclad ship USS Monitor)
by Howard Millman

Like most people, when Rod Farb visits a national monument, he carries a camera or two, lunch, and maps. But unlike the rest of us, Farb also packs air tanks - because the places he visits are under water.

An avid underwater photographer and shipwreck researcher, Farb knew it was only a matter of time before he photographed and mapped the wreck of the Civil War ironclad, the USS Monitor. What Farb didn't know was how long it would take; it took four years just to receive permission to visit the Monitor.

Ordinarily, it doesn't take years to obtain a dive permit, but the Monitor's gravesite is special. Sunk in a storm off the coast of North Carolina in 1862, the ship rested undisturbed for 111 years. In 1973, National Oceanic and Atmospheric Administration (NOAA) researchers, working from Civil War documents, discovered the Monitor in 235 feet of water 16 miles off Cape Hatteras, North Carolina.

Initially, NOAA withheld diving permission, saying an air scuba dive (which doesn't use a mixture of helicum and oxygen to prevent nitrogen narcosis) was too dangerous. Farb persevered, and in February 1990 he received approval to photograph the site. The Farb Monitor Expedition 1990 was finally a reality.

Farb knew the Monitor's depth would limit the bottom time for an air diver, so he would likely end up with less-than-perfect photographs. He was also concerned by the expedition's escalating cost, so he decided to use video a well as still photos. He could enhance the images later.

"The conditions were almost Caribbean-like" says Farb in describing the 80-degree temperature and 100-foot visibility at the ship's gravesite. But nature cooperates just so much. Even with the unusual water clarity, the Monitor's gray-and-black shell against the dark blue color of the water made for poor picture-taking conditions. Photos tended to wash out when taken from more than four feet (the effective range of the floodlights and strobe flashes.)

Photographing at greater distances requires powerful, but bulky, floodlights - both a logistical and a financial problem. Farb searched for an affordable solution, and technology supplied one. If he couldn't enhance the site conditions, reasoned Farb, he could enhance the site photographs with a computer.

He eventually selected about 350 images from among the 275,000 frames of motion and still video the crew shot at the dive site. Back in his studio, he began to experiment with computer-aided image enhancement.

A PS/2 Model 80 provided the requisite computing muscle for the task. It was lent to the Monitor Expedition by IBM and included a 110MB hard disk and a VGA monitor. Data Translation's DT-2953 black-and-white capture card grabbed the images in realtime at a 640 X 480 resolution.

Typical of graphics-capture software, Data Translation's software proved effective for image capture and preliminary contrast adjustments. For more comprehensive enhancing, however, Farb needed dedicated image-editing software. He used two software applications for image enhancement, Bioscan's Optimas and Astral Development's Picture Publisher. Both Optimas and Picture Publisher run under Windows 3.0, so they were able to use all of the Model 80's 2MB of RAM.

Since he was dealing primarily in gray-scale images, Farb's goal was to generate enough contrast to distinguish the Monitor's framework from the background of water. With Picture Publisher, he was able to accomplish just that. Optimas added component measuring and the ability to trace an object. A Hewlett-Packard Series II laser printer provided sharp hardcopies of selected images.

The enhanced images were saved in an 8-bit TIF graphic file format. To avoid running out of hard disk space, Farb compressed the stored TIF images to less than 300K (uncompressed TIF files typically take up about 975K). The compressed images were archived onto high-density 3 1/2-inch disks to leave room on the hard disk to edit new images. Microsoft Excel provided the cataloging functions to tract the collection.

Eventually, copies of all the maps, photographs, and documents will be given to NOAA for its archives. Farb will also write a book, his third that describes diving and photographing famous American shipwrecks.

When he's not exploring shipwrecks or writing about them, Farb works full time as a research associate in biochemistry at the University of North Carolina at Chapel Hill, "because," he says, "I have a mortgage to pay and occasionally like to eat." In addition to writing the book, he intends to submit papers to technical journals that detail the cost savings along with other advantages of applying computer-enhanced imaging to underwater and terrestrial site photography. "With high resolution video technology now available at a comparatively low cost, almost anyone can have access to it," he says.

In addition to Farb's photographs, a firm crew (Jack McKenney Film Productions) shot it own 16mm color film. The 16mm film was subsequently copied onto 1-inch video and edited for contrast, brightness, and color correction. Present plans call for the McKenney film to be shown by National Geographic on the Turner Network Television (TNT) in June.

Farb plans to return to the Monitor site in 1991 for further research. In the summer of 1992, he intends to photograph a World War II German U-Boat sunk off of Cape Hatteras.

I asked him why he bucks the bureaucracy, carries the cost, and deals with the danger. "I've been a scuba diver for 27 years," he says, "so as far as I'm concerned, it's just the natural thing to do. And North Carolina's coast, ~the graveyard of the Atlantic,' is the place to do it."

With hundreds of shipwrecks lying in North Carolina's coastal waters, Farb and his Model 80 have years of work waiting for them as they chronicle the final resting places of America's maritime legends.