# Is there an, "Eraser," style imaging system in real life?

**URL:** <https://boards.straightdope.com/t/is-there-an-eraser-style-imaging-system-in-real-life/536490>\
**Category:** Factual Questions\
**Created:** [April 17, 2010, 10:52pm UTC](https://boards.straightdope.com/t/is-there-an-eraser-style-imaging-system-in-real-life/536490 "2010-04-17T22:52:57Z")\
**Posts on this page:** 3\
**Page:** 2

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**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\
**Post date:** [March 18, 2022, 5:21pm UTC](https://boards.straightdope.com/t/is-there-an-eraser-style-imaging-system-in-real-life/536490/22 "2022-03-18T17:21:49Z")

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It’s certainly not the same thing, but for a very weird unexpected imaging system, have a look at **Ghost Imaging**

> **[An introduction to ghost imaging: quantum and classical | Philosophical...](https://royalsocietypublishing.org/doi/10.1098/rsta.2016.0233)**
>
> Ghost imaging has been a subject of interest to the quantum optics community for the
> past 20 years. Initially seen as manifestation of quantum spookiness, it is now recognized
> as being implementable in both single- and many-photon number regimes....

> **[Ghost imaging](https://en.wikipedia.org/wiki/Ghost_imaging#:~:text=Ghost%20imaging%20(also%20called%20%22coincidence,pixel%20(bucket)%20detector%20that%20does)**
>
> Pages for logged out editors learn more
> 
> 			 
> 
> Ghost imaging (also called "coincidence imaging", "two-photon imaging" or "correlated-photon imaging") is a technique that produces an image of an object by combining information from two light detectors: a conventional, multi-pixel detector that doesn't view the object, and a single-pixel (bucket) detector that does view the object. Two techniques have been demonstrated. A quantum method uses a source of pairs of entangled photons, each pair...

> **[Quantum camera snaps objects it cannot 'see'](https://www.newscientist.com/article/dn13825-quantum-camera-snaps-objects-it-cannot-see/)**
>
> "Ghost imaging" can photograph an object using light that didn't touch it – but physicists can't agree on the effect that makes it possible

[https://www.optica.org/en-us/about/newsroom/news\_releases/2019/researchers\_capture\_moving\_object\_with\_ghost\_imagi/](https://www.optica.org/en-us/about/newsroom/news_releases/2019/researchers_capture_moving_object_with_ghost_imagi/)

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**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\
**Post date:** [March 18, 2022, 5:46pm UTC](https://boards.straightdope.com/t/is-there-an-eraser-style-imaging-system-in-real-life/536490/23 "2022-03-18T17:46:49Z")

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> [@md-2000](#):
>
> Weird. I thought I was replying to a current thread on the main page. Or did a spam reply that revived it get deleted in the meantime?

Yeah, one of the more annoying “features” of Discourse is that even when the post that bumped a thread is deleted, the thread doesn’t un-bump. In fact, even when the bumping post is never even visible to the public at all, because it was caught for review by the automatic spam-catcher (as in this case), it still bumps the thread. I’m sure that the makers of Discourse would tell us that there’s some very good and important reason why that must be the way that a message board should work.

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**Author:** ![Galactus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/galactus/32/3581_2.png) [@Galactus](https://boards.straightdope.com/u/Galactus)\
**Post date:** [March 18, 2022, 8:28pm UTC](https://boards.straightdope.com/t/is-there-an-eraser-style-imaging-system-in-real-life/536490/24 "2022-03-18T20:28:32Z")

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Why do spammers use old threads?

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