Image Compressor Beats JPEG

Unlike jpeg algorithms, which compress an image after it is taken, a new low-profile metamaterial sensor uses microwave imaging to compress pictures as they are being recorded.

The Duke University metamaterial sensor acts as a lens to produce two-dimensional images using fewer components than conventional detectors. The findings suggest that cameras, x-ray scanners and other imaging technologies built with the device could provide a more efficient, versatile and cheaper way to take pictures for applications such as airport security scanners and collision avoidance systems for aircraft, cars and maritime vessels.

The one-dimensional metamaterial aperture, developed by scientists at Duke University, can compress images as they are being recorded. The findings suggest that cameras, x-ray scanners and other imaging technologies built with the metamaterial sensor could take pictures faster and with fewer measurements or detectors than currently needed. Courtesy of John Hunt, Duke ECE.

“By taking advantage of the unique properties of these metamaterials, we were able to create a system capable of microwave imaging without lenses or any moving parts,” said John Hunt, a graduate student working in the laboratory of senior investigator David R. Smith, William Bevan Professor of electrical and computer engineering at Duke’s Pratt School of Engineering.

The manmade material comprises a thin laminate with row upon row of tiny squares etched onto copper, each one of which is tuned to a different frequency of light. The material is flexible and durable enough to be attached to a wall, wrapped around corners or laid on the floor like a rug, making it an inexpensive alternative for a variety of sensing applications.

In many security situations, imaging systems move a single sensor device with a small aperture in front of the body of the subject, creating an effectively larger aperture, Hunt said. The scanning waves travel through clothing, but skin or other objects reflect the waves. The new device can scan the entire field at once, which would allow for faster and more efficient screening.

“Using conventional systems such as airport security cameras or collision-detection devices, you have to wait for a scan to complete before you can see an image, while the new system can scan an entire range at once,” Hunt said.

“Each individual element of the metamaterial is tuned to narrow frequency,” said Tom Driscoll, a postdoctoral fellow from the University of California, San Diego, currently working in the Smith lab. “Together, the individual elements scan the entire range to capture information about a scene very quickly.

John Hunt, left, and Tom Driscoll. Courtesy of Duke University Photography.

“This system allows us to collect and compress the image during collection, instead of later, averting the detector, storage and transmission costs associated with conventional imaging of a scene,” he said.

The findings are part of a broader trend that aims to streamline image processing in all forms, from higher resolution images in smartphones to three-dimensional medical MRI images.

The team is exploring moving the technology to three-dimensional capability in real-world settings.

The research, supported by the Air Force Office of Scientific Research, appears in Science (doi: 10.1126/science.1230054).

For more information, visit: www.duke.edu