LAYERED LENS: To take a gigapixel image, which contains more than 1,000 times the amount of information as a megapixel image, in one snapshot requires a special setup. Here, Columbia University researchers propose a ball-shaped lens, half of which is covered by secondary relay lenses, to capture the entire image with minimal distortion.Image: COURTESY OF SHREE NAYAR AND OLIVER COSSAIRT, COLUMBIA UNIVERSITY
Advances in technology tend to spoil us. PCs just a few years old have nothing on today's smart phones, and, whereas megapixel images were once the state of the art in digital photography, gigapixel images (composed of at least one billion pixels, or picture elements) are beginning to show up on the Web in vivid detail.
Gigapixel images also hold tremendous potential for providing law enforcement and the military with detailed reconnaissance and surveillance information. Long-distance images taken today by satellites or unmanned aerial vehicles (UAVs) can capture detail down to a license plate number while flying at altitudes too high for these drones to be spotted from the ground. But these images provide only a narrow view, says Ravi Athale, a consultant to the Defense Advanced Research Projects Agency (DARPA) and a senior principal scientist at MITRE Corp. in McLean, Va. He likens UAV images to seeing a battlefield or city through a "soda straw" and satellite images to an injection needle.
"We are no longer dealing with fixed installations or army tank units or missile silo units,” Athale says. “[Fighting terrorism requires] an awareness of what's going on in a wide area the size of a medium city."
Through its Advanced Wide Field of View Architectures for Image Reconstruction and Exploitation program, DARPA has for the past year been working on ways to develop a camera that can take a gigapixel-quality image in a single snapshot. This approach is novel, given that today's gigapixel images actually consist of several megapixel-sized images pieced together digitally to provide a high level of detail over a large area. This is often done using a long-lens digital single-lens reflex (SLR) camera placed atop a motorized mount. Software controls the movement of the camera, which captures a mosaic of hundreds or even thousands of images that, when placed together, create a single, high-resolution scene that maintains its clarity even when the viewer zooms in on a specific area. DARPA plans to invest $25 million over a three-and-a-half-year period in its program, which includes a component called Maximally scalable Optical Sensor Array Imaging with Computation (MOSAIC).