The basic structure for both alarm algorithms was easy to understand. To identify a moving animal, it was sufficient to overlay two or three images taken less than a second apart (at any wavelength, although there was greater accuracy in the process with the sharper visual images), and then compare the data using the knowledge that most of the scene should be unchanged. Significant miscompares (connected areas in the overlay that differed from image to image) would suggest the presence of a large moving creature.
To identify foreign objects in the field of view, the alarm algorithm took advantage of the tremendous storage capacity of the memory unit in the telescope data processing system. The near simultaneous infrared and visual images were fed into the memory unit and then crudely analyzed against a data set that contained chains of pattern recognition parameters over both wavelength regions. These pattern parameters had been developed through years of careful research and had been recently expanded by MOI to include virtually everything normal (plants, animals, reef structures, etc.) that might be seen on the ocean floor around the Florida Keys. Any large object that didn’t correlate in realtime with this existing data base would be flagged and the alarm would sound.
The alarms made it unnecessary to sit patiently in front of the screen and study the thousands of frames of data as they were received on the boat. Even Troy, a confessed “knowledge junkie” whose interest in everything was almost insatiable, grew tired of staring at the monitor after about ten minutes, particularly when the boat entered into deeper water and very little could be seen in the visual images.
A couple of solitary sharks triggered alarms and created momentary excitement about twenty minutes after the telescope was activated, but a long period void of any discoveries followed. As the afternoon waned Nick became more and more impatient. “I don’t know why I allowed myself to be talked into this wild goose chase,” he grumbled to nobody in particular. “We could have been preparing the boat for the weekend charter.”
Carol ignored Nick’s comment and studied the map one more time. They had traversed from south to north the region she and Dale had defined and were now moving slowly east along the northern periphery. Dale had constructed the search area based upon his own inferences from the questions asked him by the Navy. He probably could have pinned down the area of interest with greater certainty with a few more questions of his own, but he hadn’t wanted to arouse any suspicions.
Carol knew that the search was a little like finding a needle in a haystack, but she had thought it would he worthwhile because of the potential payoff. If she could somehow find and photograph a secret Navy missile that had crashed near a populated area… What a scoop that would be! But now she too was growing a little impatient and it was hard for her to revive her earlier excitement after the long afternoon in the sun. They would have to head back to Key West soon to ensure arrival by nightfall. Oh well, she thought to herself with resignation, at least I gave it a shot. And as my father used to say, nothing ventured, nothing gained.
She was standing all the way at the prow of the boat when suddenly alarms started coming from the memory unit next to the monitor. One ring, then two, followed by a brief silence. A third ring then sounded and was rapidly joined by a fourth. Carol rushed excitedly toward the monitor. “Stop the boat,” she shouted imperiously at Nick. But she was too late. By the time she reached the monitor, the alarms had stopped and she could not see anything on the screen.
“Turn around, turn around,” a frustrated Carol hollered immediately, not noticing that Nick was again glaring at her.
“Aye, aye, Cap-i-tan,” Nick said, jerking on the wheel with such force that Carol lost her balance. The monitor and other electronic equipment started to slide off their flimsy mountings on the top of the footlocker; they were rescued at the last minute by Troy. The Florida Queen veered sharply in the water. Despite the quietness of the ocean, a small wave came over the railing on the low side of the deck, catching Carol from the knees down. The bottom of her cotton slacks were left clinging to her calves. Her white tennis shoes and socks were drenched. Nick made no effort to hide his amusement.
Carol was about to joust with him again when the renewed ringing of the alarms diverted her attention. Regaining her squishy footing as the boat leveled off, she saw in the monitor that they were above a coral reef. And deep beneath the boat, barely discernible on the screen, were three whales of the same kind that she had seen on the beach that morning at Deer Key. They were swimming together in what appeared to be an aimless pattern. But there was more. The special alarm message code indicated that there was also a foreign object in or near to the same field of view as the desultory whales. Carol could not contain her excitement. She clapped her hands. “Anchor, please,” she shouted, and then she laughed. She saw that Troy had already thrown the anchor overboard.
A few minutes later Carol was hurriedly putting on her buoyancy vest in the aft portion of the boat behind the canopy. Her mask and her flippers had already been adjusted and were beside her on the deck. Troy was helping her by holding up the air bottle that was built into the back of the bulky vest. “Don’t worry about Nick,” Troy said. “He may be grumpy today for some reason, maybe because Harvard lost the basketball game, but he’s a fabulous diver. And he has the reputation of being the best dive teacher in the Keys.” He grinned. “After all, he taught me a couple of months ago and we’re not even supposed to be able to swim.”
Carol smiled and shook her head at Troy. “Don’t you ever stop joking?” she said. She slid her free arm through the second opening and the vest fell into place. “By the way,” she continued softly, “for an expert diver your friend certainly uses antiquated equipment.” At this moment she regretted her decision to leave her customized diving vest in the station wagon. She always used it when she dove with Dale and it had all the latest advances, such as ABC (Automatic Buoyancy Compensation) and a perfect pocket for her underwater camera. But after all the brouhaha when she came through the marina headquarters with her footlocker of electronic equipment, Carol had decided not to attract further attention by bringing in a state-of-the-art diving vest.
“Nick thinks the new vests make it too easy for the diver. He wants them to have to adjust their buoyancy manually—so that they are more conscious of how far down they are.” Troy looked Carol over. “You’re pretty light. This belt may be enough by itself. Do you normally use any weights?”
Carol shook her head and pulled the belt around her waist. Nick came around the canopy carrying his mask and flippers. He had already put on his diving vest with air bottle and his weighted belt. “Those whales of yours are still in the same spot down there,” he said. “I’ve never seen whales hang around like that. “He handed her a piece of chewing tobacco. She rubbed the tobacco on the inside of her mask (to prevent fogging) while Nick walked around behind her. He looked at her air gauge and checked both her regulator and the secondary mouthpiece that he might have to use to share her air in the event of an emergency.
Nick talked to Carol while he was making her final equipment checks. “This is your charter,” he began in what sounded like a friendly tone, “so we can go almost anywhere you want while we are down there. The dive will not be too difficult, since it’s only forty-five feet or so to the floor. However,” Nick moved around in front of Carol and looked directly in her eyes, “I want one thing thoroughly understood. This is my boat and I am responsible for the safety of the people on it. Including you, whether you like it or not. Before we dive, I want to make certain that you will follow my lead under the water.”