monitor came up with Holly leaving the dry-cleaner’s counter. He
clicked on a couple of menus.
“OK,” he said. “I’m copying it to the hard disk. As a graphics
file.”
He darted back to the video bank and nudged the tape forward one frame.
Came back to the desk and the computer captured the image of Holly
making to push open the exit door. He repeated the process three more
times. Then he printed all five graphics files on the fastest laser he
had. McGrath stood and caught each sheet as it flopped into the output
bin.
“Not bad,” he said. “I like paper better than video. Like it really
exists.”
The tech chief gave him a look and peered over his shoulder.
“Definition’s OK,” he said.
“I want blow-ups,” McGrath told him.
“No problem now it’s in the computer,” the tech said. That’s why the
computer is better than paper.”
He sat down and opened the fourth file. The picture of Holly and the
three kidnapers in a tight knot on the sidewalk scrolled onto the
screen. He clicked the mouse and pulled a tight square round the
heads. Clicked again. The monitor redrew into a large blow-up. The
tall guy was staring straight out of the screen. The two new guys were
caught at an angle, staring at Holly.
The tech hit the print button and then he opened the fifth file. He
zoomed in with the mouse and put a tight rectangle round the driver,
inside the car. He printed that out, too. McGrath picked up the new
sheets of paper.
“Good,” he said. “Good as we’re going to get, anyway. Shame your damn
computer can’t make them all look right at the camera.”
“It can,” the tech chief said.
“It can?” McGrath said. “How?”
“In a manner of speaking,” the guy said. He touched the blow-up of
Holly’s face with his finger. “Suppose we wanted a face-front picture
of her, right? We’d ask her to move around right in front of the
camera and look right up at it. But suppose for some reason she can’t
move at all. What would we do? We could move the camera, right?
Suppose you climbed up on the counter and unbolted the camera off the
wall and moved it down and around a certain distance until it was right
in front of her. Then you’d be seeing a face-front picture,
correct?”
“OK,” McGrath said.
“So what we do is we calculate,” the tech said. “We calculate that if
we did hypothetically move that camera right in front of her, we’d have
to move it what? Say six feet downward, say ten feet to the left, and
turn it through about forty degrees, and then it would be plumb face-on
to her. So we get those numbers and we enter them into the program and
the computer will do a kind of backward simulation, and draw us a
picture, just the same as if we’d really moved the actual camera right
around in front of her.”
“You can do that?” McGrath said. “Does it work?”
“Within its limitations,” the tech chief said. He touched the image of
the nearer gunman. “This guy, for instance, he’s pretty much side on.
The computer will give us a full-face picture, no problem at all, but
it’s going to be just guessing what the other side of his face looks
like, right? It’s programmed to assume the other side looks pretty
much like the side it can see, with a little bit of asymmetry built in.
But if the guy’s got one ear missing or something, or a big scar, it
can’t tell us that.”
“OK,” McGrath said. “So what do you need?”
The tech chief picked up the wide shot of the group. Pointed here and
there on it with a stubby forefinger.
“Measurements,” he said. “Make them as exact as possible. I need to
know the camera position relative to the doorway and the sidewalk
level. I need to know the focal length of the camera lens. I need
Holly’s file photograph for calibration. We know exactly what she
looks like, right? I can use her for a test run. I’ll get it set up