“Yes, sir,” Cramer replied. The ‘sir’ slipped out naturally and the Colonel smiled. He left the office, leaving Joker deep in thought, staring at the empty whisky bottle.
Cole Howard caught the morning flight to Washington, DC. As he sat in the front row of the economy section he flicked through the pack of Trivial Pursuit cards he’d brought with him. “You like playing?” asked his neighbour, an elderly woman in a neck brace. “My nephews bought me a set last Christmas. I play it all the time.”
“I dislike the game intensely,” Howard answered. The woman looked shocked as if Howard had sworn at her and she buried her head in a magazine. Howard began to go through the cards, memorising the answers.
There was a queue for taxis when he arrived at Washington Dulles International Airport but he took the wait good-naturedly. The FBI laboratories were half an hour’s drive from the airport, during which time he worked his way through another two dozen cards. On arrival, he clipped his FBI badge to his breast pocket and flashed his identification at the security guards at reception. He was told that the lab he was looking for was on the second floor. There he asked for Dr Kim. He wasn’t surprised when a woman came out to meet him, because they’d spoken several times on the phone, but he was surprised at how young and attractive she was. She was Oriental, with waist-length hair which she wore as a single braid. She had razor-sharp cheekbones and a small, delicate mouth and oval eyes which narrowed almost to slits when she smiled. “Dr Kim,” said Howard, as they shook hands. His hand seemed to dwarf hers. It was as delicate as a six-year-old’s, with nails painted a deep red.
“Call me Bonnie,” she said. “My lab’s this way.” Her high heels clicked on the tiled floor as they walked. Even with the heels the top of her forehead barely reached his shoulders, and Howard was only a little over six feet tall. She took him past several doors and into a long, thin laboratory which had white benches lining the walls and a small cubbyhole of an office at the end. On the benches in the lab were several IBM computers and racks of VCRs and monitors. One of the VCRs had been opened up and she’d been doing something with a circuit board and a soldering iron. The iron was still on and she pulled out the plug.
She poured him a cup of coffee from a percolator and sat on a swivel chair facing one of the monitors. She opened a drawer under the bench and handed him a pale blue file.
“These are prints of what I’ve been able to achieve so far,” she said. “But I wanted you to see the video with me, too. I have some suggestions which might help.”
Howard sipped his coffee as she started the video. By now he knew every second by heart, and he could watch it without emotion. He no longer grieved for the dying family, and he could listen to the woman’s last words of comfort to her son without cringing inside. They watched it together, in silence.
“This is the original video,” she said, “the same version you’ve seen in Phoenix. I’ve taken the signal on the tape and programmed it into the computer, then used it to boost the definition several-fold. To see it we’ll need a very high-definition television monitor, this one here.” She flicked a switch on a console and the video played again on a wider television screen. Howard could see the improvement immediately. Bonnie kept her hand on the pause button and as the camera panned to the ground below she pressed it. The frozen picture was much sharper than on a standard video-recorder, too; there was no fuzzy line or flickering. On the screen was one of the towers, and Howard could clearly see a figure with a rifle. The face was still blurred.
“The quality is much improved, but there are limits to what we can do with analog methods,” said Bonnie. She let the video play on. “We can get better results by digitising the video and storing it on a CD.” She patted one of the computers, an unimposing white box. “This is our image processor, which takes the video signal and digitises it. We call it a frame grabber. It can digitise images in real-time — about one-thirtieth of a second each — and save them into storage. Then we use a computer to handle and process the data. Once we’ve processed the images and cleaned them up, we can choose the frames we want on the monitor, and print them on a film recorder. That gives us much better definition. That’s what’s in the file — computer-generated pictures.”
Howard opened the file and looked inside. There was a stack of more than twenty glossy eight-by-tens. He went through them. There were photographs of the towers, and close-ups of the snipers. None was clear enough to make out their faces, however.
“That’s the best I can do with my equipment,” Bonnie said as she saw his face fall. “Not much help, I’m afraid. Though you can see that they’re better than the images we had on the screen.”
“What have you done to them?” Howard asked.
“I tried neighbourhood averaging first, but that wasn’t too helpful,” she said. “Those pictures are after I used a technique called median filtering. I could probably enhance them more if I used pixel aggregation, but that’s going to take me more time.” She smiled as she saw the deep furrows appear on Howard’s forehead. She took a sheet of paper and a pencil, and drew a square box with deft strokes. “Imagine this is a tiny piece of the screen,” she said. “That unit is as small as you can go. It’s indivisible. We call it a pixel. The camcorder in the plane was a Toshiba TSC-100, with a Canon 12:1 servo zoom lens, and it records 410,000 pixels with seven hundred horizontal lines. That’s a lot more than the average camcorder, some have fewer than 300,000 pixels on the image sensor. He had some pretty specialised equipment.”
Howard nodded. “He was a real-estate salesman, he used it to make videos of properties he was selling.”
“Ah, that explains it,” said Bonnie. “We’re lucky he had it, because anything less powerful and we probably wouldn’t see half the details we have. You can make that pixel as large as you want, it’ll still be one unit. You’ll just have a big pixel. What neighbourhood averaging does is to smooth out the image by taking an average of the colour and brightness of individual pixels in a predefined area. There was an improvement in the clarity of the images, but the edges blurred and we actually lost some detail, which was to be expected. Median filtering is a similar computer technique, but it uses a median value instead of an average value. It’s a small difference, but a significant one. I ran through a three-by-three neighbourhood and then a five-by-five, right on up to a nine-by-nine. For the worst areas I’d like to use the technique I mentioned, pixel aggregation. You choose a pixel which has properties you can clearly identify in terms of colour or texture and then you gradually move outwards, adding to it pixels of matching qualities, until you grow a defined region. That produces clusters of matching pixels, which can then be highlighted. I’m afraid it’ll take me quite a while with the equipment I have.”
Howard continued to go through the photographs as he listened to Bonnie’s explanation, most of which went way over his head. One of the pictures showed a row of bald, naked figures. “What are these?” he asked.
“Yes, I’m quite proud of those,” she said. “You could barely see them in the original, and the camera only picked them up once, but they’re there all right. They’re what the snipers are aiming at. Four dummies. The sort used in shop window displays.”
Howard put two photographs on the bench. They showed two sedan cars and a large flatbed truck. “I didn’t see these in the video,” he said.
Bonnie nodded eagerly. “They were only there for a few seconds, when the plane was spinning. The quality isn’t good, but you can see the colour and make. They’re Chrysler Imperials, one blue, one white. The truck I’m not sure about. Could be a Dodge.”
“That’s good, really good,” said Howard. He made a mental note to ask the Sheriff’s Department about tyre tracks at the scene.
The next set of pictures showed a group of three people standing together, a middle-aged man with a paunch, a young man, and a woman. The older man was holding something in his hand. There was a magnifying glass on the bench and Howard used it to examine the object.