Capturing 3D Surfaces Simply With a Flash Camera 131
MojoKid writes with this excerpt from Hot Hardware (linking to a video demonstration): "Creating 3D maps and worlds can be extremely labor intensive and time consuming. Also, the final result might not be all that accurate or realistic.
A new technique developed by scientists at The University of Manchester's School of Computer Science and Dolby Canada, however, might make capturing depth and textures for 3D surfaces as simple as shooting two pictures with a digital camera — one with flash and one without. First an image of a surface is captured without flash. The problem is that the different colors of a surface also reflect light differently, making it difficult to determine if the brightness difference is a function of depth or color.
By taking a second photo with flash, however, the accurate colors of all visible portions of the surface can be captured. The two captured images essentially become a reflectance map (albedo) and a depth map (height field)."
If you make enough simplifying assumptions... (Score:5, Interesting)
Why a flash? (Score:4, Interesting)
Why not cameras that use different wavelengths of light, etc? For example, one that works in visible light, and one that works in infrared?
How about the use of different polarized lenses to block certain wavelengths of light?
How well does this work with faces? (Score:1, Interesting)
I wonder how well this works with faces, if it works well it could be an easy way to create head busts for 3d heads for "icons" in your contact list.
Re:Article has a minor gaffe (Score:3, Interesting)
That's contrary to the article abstract. They describe using the difference between a diffuse lit scene (no shadows) and a flash lit scene (shadows only due to deviation of flash angle) where the brightness delta is used to fudge a distance/reflectivity calculation. Shadow detection is not a part of it, at least in this particular paper.
Re:Hello, what about Victorian-era stereographs? (Score:5, Interesting)
Parallax and stereoscopy both require the camera to be in two (or ideally with parallax more) positions. The ingenious thing about this idea (watch the video, it's good) is that the camera doesn't need to be moved. By taking two shots in the same spot, one with flash and one without, you can get a good depth map.
Now it's not as good as a laser scanner, but it's much cheaper and faster and smaller (since you could use any little camera). It's a very simple but ingenious idea. I'm quite surprised by the amount of detail they are able to get this way.
Of course it could be argued that parallax and stereoscopy are ways of viewing images with pseudo-depth as opposed to taking them (at least for the purpose of this article). Parallax has no real depth, but helps simulate the effect in the brain. Stereoscopy has no depth, but works just like the eyes to give the brain the data it needs to reconstruct the depth.
Re:A question for mojokid (Score:3, Interesting)
Because the NewScientist article doesn't get him the 18 billion ad impressions.
Seriously, look at the page in FireFox with adBlock. Seems... kinda bare, right? It did to me, and I opened it in Opera (where I don't have ad blocking set up) and almost every single blank space had an ad.
These are the kind of sites that require AdBlock.
yes, it's one of the above "related links" (Score:2, Interesting)
Hi!
I know they're not as conspicuous as they could be, but there are frequently stories included near the body of the new story. It took me a while to dig this one up (I remembered posting it, but that was several thousand posts ago, and a few years, too), so I hope people notice it.
https://science.slashdot.org/article.pl?sid=04/12/01/0238222 [slashdot.org]
Cheers,
timothy