Lensless cameras from fibre

Lensless cameras weave images from fibre

MIT researchers have developed light-detecting fibres that, when woven into a web, act as a flexible camera.

The new fibres, less than a millimetre in diameter, are composed of layers of light-detecting materials nested instead one another.

Possible applications include a soldier's uniform made of a special fabric that allows him to see in all directions. Or pants that could automatically report when they're dirty.

Eyes in the back of your shirt

Unlike natural or man-made lenses, which have a limited field of view and are susceptible to damage, optical fibre webs can capture images across the entire surface of a fabric. If one area is damaged, other fibres can still function to extract the image.

Each layer in the fibre include two rings of light-sensitive semiconductor only 100 billionths of a metre across, each with four tiny metal electrodes. The whole array is encased in a polymer insulator to separate it from neighbouring material.

Individual fibres measure light intensity and wavelength (colour), then convert it to an electrical signal. Signals from the mesh of fibres can then be analysed by an algorithm to produce a photographic image.

"This is the first time that anybody has demonstrated that fabric can collect images just like a camera but without a lens," said MIT Professor Yoel Fink.

After demonstrating that his prototype clothing-camera could capture a basic image of a smiley face, he added: ""While the current version of these fabrics can only image nearby objects, it can still can see much farther than most shirts can." Nice one, Yoel!

We've seen liquid camera lenses and cameras shaped like an eye, but a group of researchers from MIT's Department of Materials Science and Engineering are now taking things in yet another shape-shifting direction with a so-called "flexible camera" that uses a special fiber web instead of traditional lenses. Those fibers are each less than one millimeter in diameter, and are comprised of eight nested layers of light-detecting materials, which the researchers are able to form using an extrusion process like that used to make optical fiber for telecommunication applications. Once woven into a fabric, the researchers say the "camera" could be anything from a foldable telescope to a soldier's uniform that gives them greater situational awareness. Of course, they aren't saying when that might happen, although they have apparently already been able to use the fiber web to take "a rudimentary picture of a smiley face."