LONDON: Researchers have developed a new laser powered
camera system that creates high-resolution 3D images of objects from up to a
kilometre away. A standard camera takes flat, 2D pictures. To get 3D information,
such as the distance to a far-away object, scientists can bounce a laser beam
off the object and measure how long it takes the light to travel back to a
detector.
The technique, called time-of-flight (ToF) navigation
systems for autonomous vehicles, and other applications , but many current
systems have a relatively short range and struggle to image objects that do not
reflect laser light. Researchers have tackled these limitations and reported
their findings in the journal Optics Express.
The research team, led by Gerald Buller, professor at
Heriot-Watt University in Edinburgh, Scotland, describes a ToF imaging system
that can gather high-resolution , 3D information about objects that are
typically very difficult to image, from up to a kilometre away.
The new system works by sweeping a low-power infrared laser
beam rapidly over an object. It records, pixel-by-pixel, the round-trip flight
time of the photons in the beam as they bounce off the object and arrive back
at the source.
The system can resolve depth on the millimetre scale over long
distances using a detector that can "count" individual photons.
The ability of the new system to image objects like items of
clothing that do not easily reflect laser pulses makes it useful in a wider
variety of field situations, said Aongus McCarthy, the first author of the
study.
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