Shadows used to peer around corners

Reminds me of this work, aiming to "reverse" the light path between a projector and a camera/photosensor: https://youtu.be/p5_tpq5ejFQ

It took me longer than i'd like to admit to read it as "shadows used" "to peer around corners" not "shadows" "used to" "peer around corners", as if shadows at one point in time peered around corners but have since dropped the habit

It's not as fancy as image reconstruction but I realised years ago that I tend to look at the floor any time I'm approaching a blind corner in an office environment. It took a little longer to figure out I was subliminally looking for diffuse shadows that would indicate someone about to come round the corner.

> The information has to be reconstructed computationally from a series of measurements, in a similar way to that used in the X-ray imaging method known as computed tomography.

Of interest here may be the radon transform [1].

[1] https://en.wikipedia.org/wiki/Radon_transform

Can we get an image off any reflection, it's just a matter of decoding/filtering? Is that the news?

Because I would love to take an image of earth off of, say, Pluto. Or something further.

Reminds me of multistatic and passive radar, which were the entry subjects to my Wikipedia deep dive today.