[A] linear array of computer-controlled LED lights is held in front of a surveillance camera. Even though the camera is concealed inside a dark dome with a shroud to hide any information about which way the camera is aimed, its sightfield may be visualized by abakography. An abakographic wand is moved through the space to trace out a “darkpainting” or “sightpainting” (inverse “lightpainting”) that allows one or more abakographic cameras (e.g. one or more people wearing Meta-View Spaceglasses), to observe the surveillance camera’s sightfield. This may be done by way of 3D (three-dimensional) AR (Augmediated Reality). The color change of the abakographic wand (from black to blue in this example) indicates, over time (animated from left-to-right), the surveillance camera’s field-of-view and extent of coverage.
Accompanying this figure is the following description.
A PixStix Abakographer is swept through space like a wand. Typically there are hundreds of light sources along its length, but for simplicity, only 8 are shown here, numbered L1 through L8. Here the lightfield test color, is green. When the lightfield falls within the sightfield of a surveillance camera, the color changes to the abakographic color which is red in this example. A second camera, the abakographic camera, captures the abakograph of the wand, to build up a representation of the sight-field over time. The PixStix Abakographer contains a processor to present a special pattern, while sensing changes in response to nearby surveillance cameras.
Can someone explain how this works in simple terms (and without jargon or quoting verbatim from the paper)? How can a series of LEDs be used to detect whether a camera is 'seeing' them?