Lensless Camera Thinner than a Dime

Using a gridlike mask instead of a lens, a camera system thinner than a dime could pave the way for imaging systems embedded in flexible, foldable and even disposable media.

FlatCam detects a linear combination of light from multiple scene elements, and uses an algorithm to convert the data into images and videos. Prototypes that operate at visible and IR wavelengths were developed in the Rice University labs professors Richard Baraniuk and Ashok Veeraraghavan.

FlatCam, the tiny chip attached to the circuit board, is a lensless camera that may someday turn large or small surfaces into cameras. Images courtesy of Jeff Fitlow/Rice University.

Traditional cameras are shrinking, driven by their widespread adoption in smartphones. But they all require lenses, and the post-fabrication assembly required to integrate lenses into cameras raises their cost, the researchers said.

FlatCam does away with those issues in a camera that is also thin and flexible enough for applications that traditional devices cannot serve. FlatCams could be fabricated like microchips, with precision, speed and an associated reduction in costs, Veeraraghavan said.

"As traditional cameras get smaller, their sensors also get smaller, and this means they collect very little light," he said. "The low-light performance of a camera is tied to the surface area of the sensor. Unfortunately, since all camera designs are basically cubes, surface area is tied to thickness.

"Our design decouples the two parameters, providing the ability to utilize the enhanced light-collection abilities of large sensors with a really thin device," he said.

Rice University graduate students Jesse Adams, left, and Vivek Boominathan set up a test shot with a recent FlatCam prototype.

FlatCams may find use in security or disaster relief, the researchers said.

"Moving from a cube design to just a surface without sacrificing performance opens up so many possibilities," Baraniuk said. "We can make curved cameras, or wallpaper that's actually a camera. You can have a camera on your credit card or a camera in an ultrathin tablet computer."

FlatCam features a coded mask positioned very close to the sensor. Each aperture allows a slightly different set of light data to reach the sensor. Raw data sent to the back-end processor — for now, a desktop computer — is sorted into an image. The picture can be focused to different depths after the data is collected.

The prototypes use off-the-shelf sensors and produce 512 × 512-pixel images in seconds, but the researchers expect that resolution will improve as more advanced manufacturing techniques and reconstruction algorithms are developed.

Funding came from the National Science Foundation. The researchers will present their work at the Extreme Imaging Workshop Dec. 17 in Santiago, Chile. A paper is available on ArXiv.