Seeing Around Corners With Dual Photography

An anonymous reader writes "This project (which is part of this year's SIGGRAPH) has absolutely blown my mind. Basically they photograph an object with the photosensor at one point, and the light projector at another, and use the Helmholtz reciprocity algorithm to virtually switch the locations of the camera and projector, showing exactly what the light source "sees"! If that doesn't make sense to you, check out the research page and make sure to watch the 60MB video at the bottom. The playing card trick will leave you speechless!"

Comments

Blame The Slashdot Editors

[dohboy]

Don't blame their webserver/fileserver for not being able to see the movie they raved about.

It is the laziness and irresponsibility of the slashdot editors to not provide a bittorrent link.
I am disgusted that slashdot raves about a site/file/mpeg then DDOSs
it so that nobody sees it. This is particularly bad when a hobbyist site is crushed.

Mod me into oblivion, I don't care.

Re:Why use a camera?

[kevinank]

Rather than dual photography I would be more inclined to describe the method as real-world ray tracing. A focused pixel of light is captured for each pixel of the light source, then the scene is transformed so that the camera image is in the plane of the light source and the lighting function discovered earlier is inverted.

The article claims that there is no need to describe the geometry of the scene, and I understand why that is true for the structure of the subject, but it seems as though the geometry of the light and camera would still have to be known. Anything that isn't in view of the camera in the first image is unlit in the second image, and vice versa, but I don't understand how you would determine what transformation would result in that exchange without any information on the camera-light geometry in relation to the scene.