The Economist March 20th 2021 pp71-72|Science & technology| Espionage (2) pp72-73 “Round the bend” “How to see what is hidden from view”
Source PNAS.org see reference below.
Read the Bloomberg Businessweek article for all detail. And for the original paper see the PNAS reference below.
Summary of the article
Back in 2015 Dstl, a British government defense laboratory, set up a competition asking entrants to see inside “a locked room in a busy city” that is essentially closed off from view with “The curtains…mostly drawn, cutting off any direct line of sight for those outside.” Most recently more progress, beyond the initial competition, has been published in the Journal known as PNAS (Proceedings of the National Academy of Sciences) by Xu Feihu and Pan Jianwei (University of Science and Technology of China). Xu and Pan using lasers interrogated an apartment space in Shanghai from a distance of “1.43km away.” The room contained behind a barrier a “dummy of a human being” and in another experiment a giant H. They created a grid of 64 dots wide and 64 dots deep and hit each repeatedly with lasers until their receiving device, called SPAD (A single-photon avalanche diode), had accumulated sufficient data that would allow an algorithm to reconstruct a fuzzy but discernable object that was hidden from direct view.
How does “Non-Line of Sight imaging” work? Objects not in direct line of sight are visible if “light bouncing off them makes its way to that observer’s eyes or instruments” and if “at least some light reflects off all but the blackest most absorbing surfaces.”
While real world applications are far off from these initial successes the promise is clear for governments, organizations and businesses. As examples, NASA would be able to “see” into “caverns on the surfaces of moons and planets”, and the “autonomous-vehicle industry…[could have] their cars spot other motorists…speeding around blind corners.
Reference of the original academic publication in PNAS
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