BBC News, 16
May 2013
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Scientists
in Glasgow have discovered a low-cost way to create 3D images.
Their
system uses detectors which have a single pixel to sense light instead of the
millions of pixels used in the imaging sensors of digital cameras.
The
detectors can "see" frequencies beyond visible light, which
researchers say could open up new uses for 3D imaging in medicine and
geography.
They said
the single-pixel detectors cost "a few pounds" compared to current
systems, which cost "thousands".
It is hoped
that the system's ability to senses wavelengths far beyond the capability of
digital cameras and its low cost, could make it a valuable tool for a wide
range of industries.
Researchers
said possible uses could range from locating oil to helping doctors find
tumours.
Crossword
patterns
Prof Miles
Padgett led the team at University of Glasgow's School of Physics and
Astronomy, which developed the technique.
He said:
"Single-pixel detectors in four different locations are used to detect
light from a data projector, which illuminates objects with a rapidly-shifting
sequence of black-and-white patterns similar to crossword puzzles.
"When
more of the white squares of these patterns overlap with the object, the
intensity of the light reflected back to the detectors is higher.
"A
series of projected patterns and the reflected intensities are used in a
computer algorithm to produce a 2D image."
He said a
3D image was then created by combining images from the four detectors using a
well-known technique called "shape from shade".
This 3D
computational imaging, or ghost imaging produces detailed images of objects in
just a few seconds.
Conventional
3D imaging systems uses multiple digital camera sensors to produce a 3D image
from 2D information.
Careful
calibration is required to ensure the multi-megapixel images align correctly.
Beyond the
visible
Prof
Padgett said: "Our single-pixel system creates images with a similar
degree of accuracy without the need for such detailed calibration."
Lead author
on the paper Baoqing Sun said: "It might seem a bit counter-intuitive to
think that more information can be captured from a detector which uses just a
single pixel rather than the multi-megapixel detectors found in conventional
digital cameras.
"However,
digital camera sensors have a very limited sensitivity beyond the spectrum of
visible light, whereas a single-pixel detector can easily be made to capture
information far beyond the visible, reaching wavelengths from X-ray to
TeraHertz."
The team's
paper, 3D Computational Imaging with Single-Pixel Detectors, is published in
the journal, Science.
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