Sam Fisher- Camera Stoplights

  He started sliding, eyes fixed on the camera as it finished its scan and began turning back toward him. There would be a blind spot directly beneath the mount. He kept moving: step, slide, step, slide. . . . The camera reached its midpoint. The lens caught a glimmer of halogen light and winked at him. He could hear the hum of the pivot motor.

  He stepped beneath the camera mount and froze. "At camera one," he radioed.

  There was an art to the proper use of surveillance cameras, and luckily for him most security personnel either didn't understand the nuances of it, or were too lazy to bother with it.

  Cameras that provided overlapping coverage were usually calibrated one of three ways: synchronized, offset, and random offset. Synchronized was just that, cameras moving in unison; offset staggered camera movements to better cover gaps; random offset used computer algorithms to provide full-area coverage combined with unpredictable movement.

  The most common and the easiest to defeat was synchronized, followed by offset. Random offset was a nightmare--and of course this was the method the Burj al Arab employed. Here, in the narrow confines of the hallway where the camera spans were restricted, the problem was negligible, but later, as he penetrated deeper into the hotel, it would require some finesse.

  "Blueprint overlay on your OPSAT," Grimsdottir replied. "I've worked out the algorithim patterns. Just follow your traffic lights."

  Sam checked his screen: His next waypoint was a supply closet between this camera and the next. He was tempted to watch the cameras, but he kept his eyes fixed on the OPSAT. On the blueprint, the hall cameras were depicted as solid yellow triangles; as each camera panned, the triangles changed colors--red for stop, green for go.

  When the camera above and the next one down turned green, he trotted forward.

- Checkmate, Chapter 19