The first camera Nayar, Cossairt and their team at the Computer Vision Laboratory (part of Columbia Engineering School's Computer Science Department) created is a single-element, monocentric camera that uses a pan/tilt motor to sequentially scan a single sensor to emulate an array of tiled sensors. The second camera is a system that actually uses an array of five sensors arranged side-by-side that produces a contiguous field-of-view (FOV). In the second system the packaging around each sensor leaves some space between them. To account for this, the researchers added five secondary relay lenses placed between the spherical lens and the sensors. This configuration enables each sensor's FOV to overlap slightly so that there are no gaps in data that might distort the final image.
The third design attaches the secondary relay lenses directly to half of the ball-shaped lens (giving it a bumpy rather than a smooth look) and includes a large number of small sensors around that half of the lens. These sensors could be attached to the inside of a spherical half shell slightly larger than the lens itself. The spherical lens would then be positioned inside the half shell so that each sensor would be coupled with a relay lens. Any images viewed by the smooth part of the lens would be captured by the sensors inside the half shell.
"We want to show there is a path to getting to gigapixel cameras, video or still, using the form factor and the weight and the cost of something that would be a camera today," Nayar says. "It was deemed in the past that you could not do that without building a really complex system. What we are saying is that by using computations and simple systems, you can do it."
Athale acknowledges the potential of the work being done by Nayar, Cossairt and their team, saying, "Computational photography is crucial to providing 'persistent wide-area surveillance.'"
Other single snapshot approaches
Microsoft Research Asia is one of a handful of other groups experimenting with single-shot gigapixel imaging. Researchers there have since 2007 been developing a prototype they call the dgCam, whose high-power accordion-style lens configuration gives the device the look of an old-time large-format camera. The dgCam, which takes 1.6-gigapixel images and is not expected to be sold commercially, also uses a sensor much larger that those used in Columbia's prototypes. The dgCam, which is not intended to be a compact camera, is designed to help museums archive, manage and research ancient paintings and drawings.
Large-format cameras—which in their early days required the use of large photographic plates and films and now rely on sensors much larger than those used by the Columbia researchers—are well-suited for taking detailed pictures of small objects, says Moshe Ben-Ezra, a researcher in Microsoft Research Asia's visual computing group who designed and built the dgCam. "The lens does not move during image capture, which is essential for archival quality imaging of any object that is not entirely flat," he says. The dgCam scans images and, like the Columbia project, uses computational algorithms to capture information about those images.
Another large-format approach to taking gigapixel snapshots is the Gigapixl Project, which physicist Graham Flint formed about a decade ago. Gigapixl's camera uses 23-by-46-centimeter film—the same used in military spy planes such as the U-2, to capture images—which is then scanned and digitized to create images up to four gigapixels in size.
Gigapixel digital imagery is still in its infancy but demand for it will grow quickly as the technology develops. "In 1999, megapixel cameras were a dream," says Christopher Hills, a security consultant with Securitas Security Services who also runs the site gigapixel360.com. Now high-end digital cameras can take 25-megapixel images. "I absolutely believe it's going to be the next big step in the evolution of surveillance and video," he adds. "The world is always going to move toward bigger, faster, less expensive pictures and video."
Slide Show: Columbia Researchers' Prototype and Conceptual Gigapixel Cameras