Megapixel Images Created With One Pixel

Rice University researchers have developed a camera that creates megapixel quality images using one pixel. The technology allows cameras to use a smaller number of sensors to create higher resolution images.

Rice University engineers Richard Baraniuk and Kevin Kelly have been working for two years to build a camera that replaces the traditional digital pixel grid with an array of tiny micromirrors. Each mirror points either toward a single light-sensitive pixel or away from it.

When an image focuses on the mirrors, the light breaks into a random pattern, and their combined intensity is recorded by one pixel. Using a computer algorithm developed by mathematicians during the past two and a half years, the camera software identifies the simplest possible image consistent with the samples.

"Richard Baraniuk and Kevin Kelly are part of a growing movement in the imaging community toward intelligent image processing," said Sean Varah, CEO at MotionDSP Inc., a software company with image processing technology that reconstructs low-res video images into high. "Hardware has limits, and to get past those limits, you need intelligent software. Their work is very promising as it combines both hardware and software expertise."

Recent mathematical findings from scientists Emmanuel Candes at Caltech, David Donoho at Stanford, Terence Tao at University of California Los Angeles, and Justin Romberg at Georgia Tech makes the camera technology possible.

Related to compression algorithms, such as JPEG, the technology requires less compression, battery life and space in memory and storage, Baraniuk said.

Sharper pictures require more pixels. But denser pixel arrays also drain camera batteries faster, and most of the information recorded goes unused. To store images, the camera spends more power to convert them into a file format, such as JPEG, removing redundant information and fine details.

"The technology could allow smaller hardware, and lower power, but it also would enable us to build cameras where current digital cameras are blind, such as far infrared ultraviolet and terahertz cameras," Baraniuk said.

The terahertz light band sits between microwaves and infrared proves most interesting to Baraniuk. The research could prove an important technology for use by the military and the U.S. Department of Homeland Security because terahertz can pass through things like clothes and luggage.

Baraniuk said both Texas Instruments Inc., and the Defense Advanced Research Products Agency (DARPA) support the research.

Aside from military or homeland security applications, commercializing the technology in the future could mean developing digital cameras that have the capability to take and process images comparable to trillions of megapixels, said Georgia Tech professor Justin Romberg.

"In the near future, the technology could work well when you need to take pictures at night, where visible light isn't present," Romberg said. "Infrared comes in handy at night when the sun goes down, but objects still radiate heat."

Making the technology smaller, less expensive and practical for consumer goods comes next on the agenda, Baraniuk said. "We'll also look at making the reconstruction process as fast and efficient as possible," he said. "The math tells us random pattern are a good way to do measurements, but there are other ways."

The technology will be demonstrated at the Optical Society of America's annual meeting in Rochester, N.Y.