Slashdot Mirror
Capturing 3D Surfaces Simply With a Flash Camera
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)."
Bah! I completed my last project in exactly 6 days and used nothing but voice commands. It turned out so well I sat on my couch and ate Cheetos the entire next day. Today, there are over 6 billion users and we're only now starting to run into scalability issues.
-God
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I'm a big tall mofo.
...all sorts of problems become simple. I'd love to take a picture with some mirrors, some windows, maybe a reflective sign or two in the background, and see the funhouse effects that result. Oh, and don't forget emissive elements (lamps), which will appear to recede to infinity.
Slashdot (can't be bothered to find it) had a story several years ago about the (then old!) technique of capturing complicated 3D objects, such as car engines, by using two flash images, each with the flash located in slightly different locations. Threshholding the difference between the images gives very nice edge detection, along with very accurate depth information.
A project I'm working on uses the technique to capture information about arrowheads/spearheads.
TFA requires Flash.
Why didn't you just link to the more informative New Scientist article that the blog you linked quoted?
mcgrew's razor: Never attribute to stupidity that which can be explained by greedy self-interest
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.
Comment forecast: Bits of genius surrounded by a sea of mediocrity.
"shooting two pictures with a digital camera -- one with flash and one without. "
This difference has already been well-expressed across the internet for years.
Unfortunately unlocking the minigame can be nearly impossible if you have the wrong arbitrarily-assigned game character. Of course you could modify your character and change your character's gear to make it a little easier, but that's even more work and expense and doesn't make a big difference. There's also a way to pay your way into one minigame session but you'll have to be discreet about it unless you want to start another minigame that involves a lot of not-fun stuff like carefully balancing a slippery bar of soap.
"When information is power, privacy is freedom" - Jah-Wren Ryel