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)."
Creating 3D maps and worlds can be extremely labor intensive and time consuming.
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.
Your project is a case study in bad management, though. Sure, you completed the whole thing in six days, but what are we left with? Documentation that's cryptic at best, and literally billions of bugs.
The divide-by-zero exception is hardly fair. How can he fix a bug that we can't even replicate? As soon as the LHC comes on-line, we can file an official bug report. Until then, let him off the hook.
He does at least seem to fix hacking vulnerabilities though. According to accounts there used to be a lot more magic about only a few centuries ago. Or maybe the talent just matured and moved over to the more challenging but reliable fileds of reverse engineering and repurpousing the apparrently intentional features.
If only similar attention was directed to safety...
And don't get me started on the all of the exploits you left open. Sure, you provided each of us with our own anti-virus system, but if your project had been well thought out there would be no possibility of viruses and worms to begin with.
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.
...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.
Yeah, this only seams to work with lamertian surfaces in flat-lit enviroments.
That's not the biggest problem though, i am a 3d-artist, and it's a pain to try to make a tiling texture map out of a picture containing more than three channels, due to stupid limitations in all 2d applications.
It's often more efficient to first make the color texture tile, then create a heightmap from that data. I guess that's why they are targetting scientific applications such as archeology, that requires more accuracy, a
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.
But this time the camera stays fixed and there is one without flash and the other with it. Allowing for 3D Cameras to be made on the cheap by just a firmware upgrade (one click of the camera takes 2 shots 1 without flash the next with. Your way is different as it requires the camera to have 2 flash thus needed the making of new cameras.
You're right -- my way requires two flashes (it really doesn't, but we found it slightly more effective that way). The old slashdot article which I mention (but don't reference) also talked about only needing one camera. I think that it said that Chilton's Repair Manuals was using both techniques to produce their series of DVDs. Of course, I could be really wrong!
NOT old news. Google for "2008 siggraph papers". Read the paper. Google for "2004 siggraph papers". Read about the old paper. Note the differences. Tim Rowley posts links to the papers from each year, so his site is recommended. Virtually all of these image-processing-related news items can be read long before they reach slashdot simply by keeping up with the latest papers from siggraph.
In case you're lazy, the old paper is "Non-photorealistic Camera: Depth Edge Detection and Stylized Rendering Using a Multi-Flash Camera". Oddly, it's offline now. But I do have a copy of it on my hard drive. If you're not lazy, I HIGHLY recommend perusing all of the years' papers listed on Tim's site.
Perhaps the previous slashdot story wasn't "old" -- if you count things post-2004 as "new". However, even the paper in the.pdf notes that people have been concertedly using these techniques since 1998, and I happen to know that a lot of the work was pioneered as early as the mid-1940's with depth-maps and stereograms. The new work IS nice, but it's not totally new.
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.
This is quite unusual for a university. Many schools have a department of computer science or a school of computer science. But combining that with a school of Dolby Canada is quite unusual. What kind of degrees in Dolby Canada do they offer?:-)
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.
This is just a way to automatically generate surface bump maps. It does not really capture depth information (like a Z-buffer).
Conceptually it seems simple enough (take a photo with shadows from a light source not in line with the camera, take another where all the shadows are in line with the camera (making them virtually invisible), tell the software which direction the light is coming from in the first photo, and let it figure out the relative height of each pixel, by analysing the difference between it and the uniform (flash-lit) version, after averaging the brightness of the two. It's similar to the technique some film scanners use to automatically remove scratches.
I can think of a lot of cases where it won't work at all (shiny objects, detached layers, photos with multiple "natural" light sources, photos with long shadows), but still, for stuff like rock or tree bark textures it should save a lot of time. As the video suggests, this should be very pretty useful for archaeologists.
Actually you can use a bump map (which just changes the angle light is reflected without deforming the actual surface) to create a displacement map (which actually moves the polygons up and down). You just have to play a little with the depth to get it right. And when using something like RenderMan which does displacement almost as fast as other renderers do bump maps it doesn't take long to figure out the right depth.
Well, yes and no. The problem isn't how you use the map (to fake the normals or actually displace vertices), the problem is what kind of maps this technique can create. And my point is that it can't handle (for example) the Z-range of something like a person's face. Anything deep enough to actually cast shadows over other (relevant) parts of the geometry will break it (a shadow will appear much darker and the algorithm will assume it's a suface facing away from the light (or a hole). Use the result as a dis
First an image of a surface is captured with 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 without flash, however, the accurate colors of all visible portions of the surface can be captured.
This is reversed, the flash-lit image will show you the reflectance (and possibly some depth) information, whereas the non flash-lit image will show you the bare color map for the scene (provided the scene is properly lit to begin with.) FTFY!
No, with flash (light source coming from the camera) shows the colors without shadows; i.e. without color perspective. Without flash (light source at an angle to the model/subject) shows the deeper parts in shadow (known to us former art students as "color perspective").
You could actually fo this with two flashes, provided one was on the camera and one to the side. The fact that it flashes has nothing to do with it, it has to do with the angle of the light sources.
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.
RTFA. Because it is a cheap method. This way you do not need expensive infrared cameras or polarizers or, as mentioned in the article, laser equipement.
And the great thing is, the results are perceived as as good as those obtained from more expensive equipement.
Can anyone elucidate why this is so whizbang neato when we've had 3D photography ever since someone with a camera figured out about parallax [wikipedia.org]? Why is this different from stereoscopy [wikipedia.org]?
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.
Amateurs. (Score:5, Funny)
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
.
Re:Amateurs. (Score:5, Funny)
Yeah, but look at how bloated your operating systemn is!
Parent
Re:Amateurs. (Score:5, Funny)
Parent
Re: (Score:3, Funny)
There's a reason for that... (Score:4, Informative)
Obligatory XKCD [xkcd.com]
Parent
Re:Amateurs. (Score:5, Funny)
Your project is a case study in bad management, though. Sure, you completed the whole thing in six days, but what are we left with? Documentation that's cryptic at best, and literally billions of bugs.
Parent
Re:Amateurs. (Score:5, Funny)
And don't get me started on that unhandled divide-by-zero exception!
Parent
Re:Amateurs. (Score:5, Funny)
The divide-by-zero exception is hardly fair. How can he fix a bug that we can't even replicate? As soon as the LHC comes on-line, we can file an official bug report. Until then, let him off the hook.
Parent
Re:Amateurs. (Score:5, Funny)
He does at least seem to fix hacking vulnerabilities though. According to accounts there used to be a lot more magic about only a few centuries ago. Or maybe the talent just matured and moved over to the more challenging but reliable fileds of reverse engineering and repurpousing the apparrently intentional features.
If only similar attention was directed to safety...
Parent
Re: (Score:3, Funny)
Re:Amateurs. (Score:4, Funny)
Gameplay sucks, just one endless grind.
Parent
Re:Amateurs. (Score:5, Funny)
Obviously, you haven't unlocked the right minigame. It's a short game, but it makes grinding fun.
Parent
Oh, you make it sound so easy... (Score:5, Funny)
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.
Parent
Re: (Score:3, Funny)
I used to think so too. But once I got my HDTV set up, the resolution on my back yard's just not that impressive.
If you make enough simplifying assumptions... (Score:5, Interesting)
Re: (Score:3, Insightful)
That's not the biggest problem though, i am a 3d-artist, and it's a pain to try to make a tiling texture map out of a picture containing more than three channels, due to stupid limitations in all 2d applications.
It's often more efficient to first make the color texture tile, then create a heightmap from that data. I guess that's why they are targetting scientific applications such as archeology, that requires more accuracy, a
Quite old news (Score:5, Informative)
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.
Re:Quite old news (Score:5, Informative)
But this time the camera stays fixed and there is one without flash and the other with it. Allowing for 3D Cameras to be made on the cheap by just a firmware upgrade (one click of the camera takes 2 shots 1 without flash the next with. Your way is different as it requires the camera to have 2 flash thus needed the making of new cameras.
Parent
Re: (Score:2)
You're right -- my way requires two flashes (it really doesn't, but we found it slightly more effective that way). The old slashdot article which I mention (but don't reference) also talked about only needing one camera. I think that it said that Chilton's Repair Manuals was using both techniques to produce their series of DVDs. Of course, I could be really wrong!
Re:Quite old news (Score:5, Informative)
Parent
Re: (Score:2)
http://groups.csail.mit.edu/graphics/pubs/siggraph2004_nprcamera.pdf [mit.edu]
Perhaps the previous slashdot story wasn't "old" -- if you count things post-2004 as "new". However, even the paper in the .pdf notes that people have been concertedly using these techniques since 1998, and I happen to know that a lot of the work was pioneered as early as the mid-1940's with depth-maps and stereograms. The new work IS nice, but it's not totally new.
Re: (Score:2)
The new work IS nice, but it's not totally new.
Of course. Not much work is totally new. But it's new enough to be accepted into Siggraph, which is not an easy conference to get into.
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
Flash in a camera? (Score:2, Funny)
They make a version of Flash for digital cameras? Is it secure?
Re: (Score:3, Funny)
Re: (Score:2)
The School of Computer Science and Dolby Canada (Score:2)
This is quite unusual for a university. Many schools have a department of computer science or a school of computer science. But combining that with a school of Dolby Canada is quite unusual. What kind of degrees in Dolby Canada do they offer? :-)
Re: (Score:3, Funny)
Primarily "Blinding Yourself with Science", with a minor in "Sound and Signal Processing".
Cheers
Warning: (Score:5, Funny)
TFA requires Flash.
Re: (Score:2)
Mod parent up funny?
A question for mojokid (Score:5, Insightful)
Why didn't you just link to the more informative New Scientist [newscientist.com] article that the blog you linked quoted?
Re:A question for mojokid (Score:5, Insightful)
Parent
Re: (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.
Just buy 3d camera (Score:3, Informative)
Homemades.
http://www.ghouse.com/daniel/stereoscopy/equipment/index.html [ghouse.com]
http://www.teamdroid.com/how-to-make-a-cheap-digital-camera/ [teamdroid.com]
Store
http://www.3dstereo.com/viewmaster/cam-kal.html [3dstereo.com]
Now where's the download link for the GIMP plugin? (Score:2)
That's really freakin cool. How long before there's a GIMP plugin for this? I'd like it by 3pm Pacific please.
Don't get too excited (Score:4, Informative)
This is just a way to automatically generate surface bump maps. It does not really capture depth information (like a Z-buffer).
Conceptually it seems simple enough (take a photo with shadows from a light source not in line with the camera, take another where all the shadows are in line with the camera (making them virtually invisible), tell the software which direction the light is coming from in the first photo, and let it figure out the relative height of each pixel, by analysing the difference between it and the uniform (flash-lit) version, after averaging the brightness of the two. It's similar to the technique some film scanners use to automatically remove scratches.
I can think of a lot of cases where it won't work at all (shiny objects, detached layers, photos with multiple "natural" light sources, photos with long shadows), but still, for stuff like rock or tree bark textures it should save a lot of time. As the video suggests, this should be very pretty useful for archaeologists.
Re: (Score:2, Informative)
Re: (Score:3, Informative)
Well, yes and no. The problem isn't how you use the map (to fake the normals or actually displace vertices), the problem is what kind of maps this technique can create. And my point is that it can't handle (for example) the Z-range of something like a person's face. Anything deep enough to actually cast shadows over other (relevant) parts of the geometry will break it (a shadow will appear much darker and the algorithm will assume it's a suface facing away from the light (or a hole). Use the result as a dis
Outside the box (Score:2, Insightful)
Probably has significant potential in the pr0n industry.
Article has a minor gaffe (Score:2)
First an image of a surface is captured with 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 without flash, however, the accurate colors of all visible portions of the surface can be captured.
This is reversed, the flash-lit image will show you the reflectance (and possibly some depth) information, whereas the non flash-lit image will show you the bare color map for the scene (provided the scene is properly lit to begin with.) FTFY!
Re:Article has a minor gaffe (Score:4, Informative)
No, with flash (light source coming from the camera) shows the colors without shadows; i.e. without color perspective. Without flash (light source at an angle to the model/subject) shows the deeper parts in shadow (known to us former art students as "color perspective").
You could actually fo this with two flashes, provided one was on the camera and one to the side. The fact that it flashes has nothing to do with it, it has to do with the angle of the light sources.
Parent
Re: (Score:2)
Sounds like what you'd actually want is one with no depth information from lighting at all, and one with only depth information from flash.
The fully lit one would contain the base colours, the flash one would drop off the brightness as the square of distance.
Of course, as a voxelmap, I'd argue that it's not very useful to 99% of applications...
Re: (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.
so.... (Score:2)
Much like the printing press, I can only assume this technology will find its first commercial success in pornography. Some angles are worth hiding.
hello.jpg (Score:2)
3d goatse! Awesome!
Also, that would be quite a depth calculation!
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?
Re: (Score:2, Informative)
RTFA. Because it is a cheap method. This way you do not need expensive infrared cameras or polarizers or, as mentioned in the article, laser equipement.
And the great thing is, the results are perceived as as good as those obtained from more expensive equipement.
Hello, what about Victorian-era stereographs? (Score:2)
Can anyone elucidate why this is so whizbang neato when we've had 3D photography ever since someone with a camera figured out about parallax [wikipedia.org]? Why is this different from stereoscopy [wikipedia.org]?
Bemused,
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.
Parent
The differences with having Flash in photos (Score:5, Funny)
"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. [imageshack.us]