Defense News: It appears there is a need for Giga-pixel resolution sensors in security applications:
"Today there are two kinds of surveillance sensors in use by the U.S. military: high resolution sensors that offer only a narrow field of view, and low resolution sensors that offer a wide view.
That creates a problem, as described in this DARPA scenario: A UAV (unmanned aerial vehicle) operator with a high resolution sensor watches as two suspects enter a building. But when they leave, they walk away in different directions.
Which one does the operator follow? His narrow-view sensor can't follow both, and a wide-view sensor isn't sharp-eyed enough to see either.
The ARGUS-IS - the Autonomous Real-Time Ground Ubiquitous Surveillance Imaging System - can spot and track "65-plus" targets simultaneously from altitudes higher than 20,000 feet, according to the sensor's inventor, BAE Systems. DARPA awarded BAE an $18.5M contract in late 2007 to build the ARGUS-IS.
Built around a 1.8-Gigapixel digital camera, ARGUS-IS has sharp-enough resolution to identify and track individual people from four miles up in the sky. It's housed in a 15-foot-long pod that's designed to be attached to the underside of a large UAV. During the February test flight, it was attached to the belly of a Black Hawk helicopter.
The camera is made up of 368 5MP video chips mounted in four separate cameras. The images from each camera then are merged into a single large, high-definition image."