A fibre-optic cable the thickness of a human hair can transmit accurate 3D images in real time, creating a tiny flexible camera.
at the University of Glasgow, UK, and his colleagues have developed a system several orders of magnitude smaller than pre-existing cameras based on fibre-optic cable. The system uses a cable that is 40 centimetres long and 50 micrometres in diameter. It can take 3D pictures of objects up to 2.5 metres away.
The camera works similarly to a lidar scanner, which gauges distance by sending out pulses of light and measuring how long they take to bounce back. Light sent down the fibre-optic cable does much the same in miniature, determining the size and shape of an object to a millimetre鈥檚 accuracy. The camera makes more than 23,000 of these measurements every second. 鈥淭hat allows us to build up a 3D image of whatever鈥檚 at the end of the fibre,鈥� says Padgett.
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鈥淭he problem [with these] fibres is that a narrow pulse does get smeared out,鈥� says Jurgen Schmoll at Durham University, UK. He says what is good about the new device is that the team accounts for this by sending a pulse from a calibration laser through the cable to see how it distorts.
鈥淚t鈥檚 easy to say it has medical applications, but I think it also has applications in industrial inspection, and potentially surveillance,鈥� says Schmoll. Padgett is currently working on threading the fibre through a needle as a way of deploying the cable, which could allow it to penetrate human tissue.
The current version of the system uses a 60-centimetre by 60-centimetre laser projector to create the light pulse, but Padgett hopes to replace this with one half the size.
Padgett also wants to extend the length of the fibre to 2 metres or more, although that would require using a different type of fibre that would give higher resolution in the middle of the image and lower resolution at the edges. 鈥淭hat might not be a bad thing,鈥� he says. 鈥淭hat鈥檚 what the [human] eye does.鈥�
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