In a few years, if you're in a theater watching some sci-fi robot thriller, a real-life battle of the machines might unfold quietly before you: gadgets at the front of the house may seek out the optical signatures of bootleggers' camcorders, then fire narrow beams of light directly into the lenses, blinding the cameras and saving the day for Hollywood's bottom line.

With the Motion Picture Association of America estimating that piracy of newly released movies involves in-theater camcorders 90 percent of the time, a counter­offensive is taking shape. Technology proto­typed by researchers at the Georgia Institute of Technology in June exploits the fact that all digital cameras use light-­catching sensors that also reflect light back. The Georgia Tech system shines a weak infrared beam--invisible to humans--into the audience and identifies cameras by the reflected infrared light. If the system spots a camcorder, it zaps it with a narrow beam of white light, producing large splotches on the recording. Gregory Abowd, the computer scientist who led development of the technology, has launched a startup company to commercialize it, DominINC.