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)."

Comments

If you make enough simplifying assumptions...

[jeffb (2.718)]

...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.

Why a flash?

[phorm]

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?

Re:Hello, what about Victorian-era stereographs?

[MBCook]

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.