×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

Seeing Around Corners With Dual Photography

timothy posted more than 8 years ago | from the expand-e6-expand-expand dept.

Graphics 381

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!"

cancel ×
This is a preview of your comment

No Comment Title Entered

Anonymous Coward 1 minute ago

No Comment Entered

381 comments

download faster, dammit (-1, Offtopic)

Anonymous Coward | more than 8 years ago | (#12487083)

Gah, i'm so not going to get that downloaded before the 'effect' kicks in...

Can't wait (1)

WolfCub1000 (878666) | more than 8 years ago | (#12487084)

I can't wait for this kind of technology to allow more realistic games based off of actual locations, especially in games like SOF and Max Payne...

Does it work for... (2, Interesting)

Gentlewhisper (759800) | more than 8 years ago | (#12487101)

Suppose you shine a projector upwards from the ground.... and take a photo of a girl... what will the technique generate?

Re:Does it work for... (2, Funny)

Anonymous Coward | more than 8 years ago | (#12487132)

... An invasion of privacy lawsuit?

Re:Does it work for... (2, Informative)

Spacejock (727523) | more than 8 years ago | (#12487141)

A jail term. Or if you're really lucky, a fine and a photo in the local paper. ;-)

Re:Does it work for... (1, Informative)

Anonymous Coward | more than 8 years ago | (#12487205)

Not what you think it does. The algorithm can only reconstruct points which participate in the light transport from the projector to the camera. Light which is absorbed in the scene won't be traced.

Re:Does it work for... (0)

Anonymous Coward | more than 8 years ago | (#12487318)

To be more precise: The algorithm switches the positions of the light source and the camera(s). The camera positions become positions of lights and the projector position becomes the position of a camera. Now, if the camera(s) can't see the light which is cast by the projector, the virtual camera also can't see the light which is cast by the virtual light(s). What you want to see is in the shadow. To see anything, you'd have to have a (structured) light source and a camera pointed at the object of interest, so there's nothing to gain in that special application.

Re:Does it work for... (1)

tomhudson (43916) | more than 8 years ago | (#12487414)

Why go to all that trouble when you can get one of those Sony cams that saw more of the spectrum than normal, and let you photog. your neighbour in the nude, even when she was clothed.

Or go here [advanced-i...igence.com], for those "special night photography" accessories for your Sony XRay cam.

Re:Can't wait (0)

Anonymous Coward | more than 8 years ago | (#12487226)

I suggest you start saving money for a RAM expansion then. These kinds of algorithms eat memory like no tomorrow. They're talking about 8D fields!

buh-bye server... (4, Funny)

REBloomfield (550182) | more than 8 years ago | (#12487085)

make sure to watch the 60MB video at the bottom. The playing card trick will leave you speechless!"

The exploding server one has already rendered me speechless. Why in the name of god do they do it!

Re:buh-bye server... (0)

Anonymous Coward | more than 8 years ago | (#12487394)

I knew as soon as I read "60MB video" that the server was a goner.

60MB times the number of /. readers equals recipe for disaster.

Re:buh-bye server... (1, Funny)

BRonsk (759601) | more than 8 years ago | (#12487415)

And now, mirrordot is slashdotted as well... What a pity.

We need a mirror-mirrordot.org!

huh (-1, Offtopic)

Anonymous Coward | more than 8 years ago | (#12487086)

what the heck is going on

Why don't the editors link to mirrordot? (4, Informative)

cortana (588495) | more than 8 years ago | (#12487091)

Re:Why don't the editors link to mirrordot? (1)

mustafap (452510) | more than 8 years ago | (#12487138)

Mirror, mirror on the wall,
Where is the file I'm looking for?

Files are for people who use editors (-1, Offtopic)

smitty_one_each (243267) | more than 8 years ago | (#12487274)

Of course, real men don't actually use an editor, instead going for the minimal number of processes possible.
You need to get into power user mode, using only the shell operators like > and >>, plus the occasional cat and sed, to effect editing.
If no one is looking, you can use less for an actual glance at what you're editing.
That little burning sensation you feel if you stoop to using less? That's pride. Fsck pride. Wuss.

Re:Files are for people who use editors (-1, Offtopic)

tomhudson (43916) | more than 8 years ago | (#12487364)

echo -n "what the fuck" > comments.txt
echo "are you talking about d00d?" >> comments.txt
echo -n "If they were to give notepad some " >> comments.txt
-echo -n "Wordstar keybindings, it would be " >> comments.txt
-echo "almost a replacement for vi AND emacs." >> comments.txt

cat comments.txt
Real men don't need less. Real men cat. And we can hit that pause key fast! less is for old koreans.

And if you're stuck on a windows platform, you can always use debug to edit your text files.

Re:Why don't the editors link to mirrordot? (1)

sH4RD (749216) | more than 8 years ago | (#12487159)

How can they link to material that hasn't been mirrored yet?

Re:Why don't the editors link to mirrordot? (2, Insightful)

cortana (588495) | more than 8 years ago | (#12487187)

They can edit the article once Mirrordot has completed mirroring. It does it so quickly that I assume it has a subscription and can take advantage of the subscriber-only period.

Re:Why don't the editors link to mirrordot? (1, Offtopic)

nmg196 (184961) | more than 8 years ago | (#12487171)

Why do you need to link to mirrordot if the original is hosted at Stanford?!

Re:Why don't the editors link to mirrordot? (0)

Anonymous Coward | more than 8 years ago | (#12487317)

Because it's down?!?!?!!11oneeleven!1

Re:Why don't the editors link to mirrordot? (1, Insightful)

Anonymous Coward | more than 8 years ago | (#12487326)

because not even Sanford can handle the traffic and now we cant even see the html never mind the video ?

not every server at sanford is sitting directly facing internet2 with load balancing server clusters and tb of ram, perhaps ?

Re:Why don't the editors link to mirrordot? (1)

Mariukenas (824757) | more than 8 years ago | (#12487196)

And to kill the phenomenon of slashdoting ?
Your are enemy to modern net culture!!! :)

Re:Why don't the editors link to mirrordot? (4, Funny)

Vo0k (760020) | more than 8 years ago | (#12487286)

Because then Mirrordot would mirror Slashdot, including link to mirrordot mirror of slashdot including...
Kaboom, Slashdot and Mirrordot slashdotted each other!

OMG, we've been Helmholtz'ed (-1)

Anonymous Coward | more than 8 years ago | (#12487311)

Where am we anyway?

University of Virginia Mirror to Video (4, Informative)

Pavan_Gupta (624567) | more than 8 years ago | (#12487316)

Well, I've begun the download for this video, and seeing as how mirrordot is being slashdotted, I have only downloaded about 20 megs out of the 60 meg file, with an ETA of about 25 minutes. At any rate, I've put the mirror up linking to the file that's being created -- and in 25 minutes that file will be complete, until then it'll be some percentage of the total.

Enjoy. [virginia.edu]

Re:University of Virginia Mirror to Video[disable] (1)

Pavan_Gupta (624567) | more than 8 years ago | (#12487523)

Whoa. UVa's outbound connection just got crushed -- I can help someone create a torrent, but my mirror can't sustain this. I've already dished out a couple gigs of data -- and the server basically dropped.

Seriously, I was downloading of of the UVA Residence conection from from www.people.virginia.edu at nearly a megabyte a second, and I can't access the server any longer -- even my access to our mail server and network file storage was getting slowed.. Nasty phone calls will come from this.

Someone would be much loved if they created a torrent for this -- and if that somebody needs fast access to this file, just send an e-mail to pg8p At virginia magicdotofdoom edu, and I will give you direct access to the file so you can download it quickly and get the torrent up.

Sorry amigos -- a few hundred KB per sec is okay, but megabytes per second of bandwidth usage is not going to fly. A torrent would work magic here.

Re:Why don't the editors link to mirrordot? (3, Insightful)

Black Morning (873787) | more than 8 years ago | (#12487426)

Even mirrordot got crushed... Seriously, what was the submiter thinking? Not to mention the editors.

The real question is why nobody made a torrent of this video before the story went live. Bittorrent is one of the posterchildren of open source and legit p2p, it's unfortunate that here on Slashdot, the center of the community, nobody ever bothers to use it for it's intended purpose. We have an opportunity to put a great FOSS project to a vitally needed user, but instead they choose to continue crushing servers. Sigh...

Re:Why don't the editors link to mirrordot? (0)

joshuao3 (776721) | more than 8 years ago | (#12487527)

The original poster has the video, presumably. Perhaps he'll so kind as to post a torrent.

He say you Blade Runner... (1)

Hell O'World (88678) | more than 8 years ago | (#12487092)

Wasn't there a scene in Blade Runner where he used something like that?

Re:He say you Blade Runner... (1)

Spacejock (727523) | more than 8 years ago | (#12487127)

Wasn't it Arnie in Total Recall? (Disclaimer: I may be totally and utterly wrong.)

Re:He say you Blade Runner... (1)

mav[LAG] (31387) | more than 8 years ago | (#12487239)

Can't remember Arnie using a photo like that in Total Recall but in Blade Runner, Deckard "3D analyses" a photo he confiscated from Leon's apartment to see around a corner and get a pic of Zhora, thanks to a reflection in a mirror.

Re:He say you Blade Runner... (1)

mikael (484) | more than 8 years ago | (#12487190)

Are you referring to the scene where he zooms into a photograph using a automated magnifier?

From what I remember, he caught the reflection of the dancers from a mirror partially visible through the bathrooom door.

Re:He say you Blade Runner... (0)

Anonymous Coward | more than 8 years ago | (#12487406)

yup but it could change the point of view...

Re:He say you Blade Runner... (1)

hedge_death_shootout (681628) | more than 8 years ago | (#12487422)

Yeah but as he pans and zooms, the viewpoint of the 'camera' changes, so he can look round obstacles.

I just wrote it off as the usual movie crapness, like when the techno-whizkid 'image enhances' a picture by utterly laughable amounts so you can read the name badge on some guy who was initially hidden within a single pixel.

Re:He say you Blade Runner... (1)

mockenh (871921) | more than 8 years ago | (#12487451)

The game has a device that allows to "walk through" pictures. It is, for example, used to read the plate of a car parking outside a shop, the photo being taken from inside the shop where only a corner of the car is visible. The device used in the movie was a magnifier used to focus in on a reflection.

Never! (4, Funny)

beders (245558) | more than 8 years ago | (#12487093)

make sure to watch the 60MB video at the bottom

I find it highly unlikely that many will manage that :0

OK, that's just cruel... (0)

Anonymous Coward | more than 8 years ago | (#12487098)

> and make sure to watch the 60MB video at the bottom.

Yeah, I'm sure Standford can afford the bandwidth, but you're giving ideas to your fellow slashdotters...

(Or maybe not, I can't connect).

Mirrors needed? (1)

bernywork (57298) | more than 8 years ago | (#12487099)

I think we are going to need a couple of mirrors of this file or get a torrent setup....

I am trying, I have 26 meg of the file down now, but the speed of my download is definately slowing.

Quick! (2, Funny)

Jozer99 (693146) | more than 8 years ago | (#12487102)

Quick, shine a light into your monitor and take a picture. Then use their software to capture an image of their exploding server!

around corners? (2, Interesting)

psyon1 (572136) | more than 8 years ago | (#12487106)

Where does seeing around corners come in?

Re:around corners? (1)

HaydnH (877214) | more than 8 years ago | (#12487148)

"If that doesn't make sense to you, check out the research page..."
errr I read the research page and it still doesn't make sense... any photographers on /. care to elaborate?? Or perhaps anybody that managed to download the video before 'the effect' kicked in? Haydn.

Re:around corners? (5, Informative)

Anonymous Coward | more than 8 years ago | (#12487186)

Seeing around corners is really stretching it. You switch positions with the light source, so you can technically look at the scene from a point which is "around a corner". What they so casually mention as "structured lighting" is really the key to the whole algorithm and means that the light source shines a pattern on the scene which then allows the camera to retrace where every bit of light it sees is coming from. This means that the light source needs to be part of the scheme. You won't be able to switch yourself into the position of arbitrary lights on the street.

Re:around corners? (2, Informative)

indy (23876) | more than 8 years ago | (#12487390)

The parent is right. You will not be able to see things that were hidden to the camera.

All you are going to see is the scene as if camera and light source had switched places. Everything that was hidden to the camera in the original image will fall into black shadow regions in the generated image.

Re:around corners? (1, Informative)

Anonymous Coward | more than 8 years ago | (#12487520)

The virtual camera in the position of the projector will see things which the real camera can't see. The important point is that the camera becomes the virtual light source. If a light at the position of the real camera would not light the scene sufficiently for a camera at the position of the projector to capture a good picture, then the algorithm won't produce a good result either. In the pictures on the website you can see that the shadow on the computed picture is actually like you would expect when the scene is lighted from the position of the camera. The algorithm does not change the camera position without changing the light position.

rays? (2, Insightful)

dhbiker (863466) | more than 8 years ago | (#12487108)

isn't this just the same in principle as ray tracing? or am I missing something

Re:rays? (3, Informative)

Wyzard (110714) | more than 8 years ago | (#12487332)

If you mean in the sense that POV-Ray does, then no, this is very different. It's an "image-based" rendering technique, which means that you create new images using photographs and other such real-world measurements as input. Conventional ray tracing gives you pictures of models built in the computer's memory, which might approximate a real-world object.

The important difference is that you don't have to build a computer model of the geometry you're trying to render. This is both a help because many real-world objects are hard to model accurately in a computer, and a hindrance because you can only render pictures of objects that you actually have in the real world.

April 1st (0)

Anonymous Coward | more than 8 years ago | (#12487114)

Yeah, um, hey! April 1st was a bit ago...

Wow.... (0)

Anonymous Coward | more than 8 years ago | (#12487137)

It only took five minutes to kill the server. That has to be some kind of record.

ARTICLE CONTENTS (5, Informative)

Anonymous Coward | more than 8 years ago | (#12487143)

Dual Photography

Abstract

We present a novel photographic technique called dual photography, which exploits Helmholtz reciprocity to interchange the lights and cameras in a scene. With a video projector providing structured illumination, reciprocity permits us to generate pictures from the viewpoint of the projector, even though no camera was present at that location. The technique is completely image-based, requiring no knowledge of scene geometry or surface properties, and by its nature automatically includes all transport paths, including shadows, interreflections and caustics. In its simplest form, the technique can be used to take photographs without a camera; we demonstrate this by capturing a photograph using a projector and a photo-resistor. If the photo-resistor is replaced by a camera, we can produce a 4D dataset that allows for relighting with 2D incident illumination. Using an array of cameras we can produce a 6D slice of the 8D reflectance field that allows for relighting with arbitrary light fields. Since an array of cameras can operate in parallel without interference, whereas an array of light sources cannot, dual photography is fundamentally a more efficient way to capture such a 6D dataset than a system based on multiple projectors and one camera. As an example, we show how dual photography can be used to capture and relight scenes.

(a) Conventional photograph of a scene, illuminated by a projector with all its pixels turned on. (b) After measuring the light transport between the projector and the camera using structured illumination, our technique is able to synthesize a photorealistic image from the point of view of the projector. This image has the resolution of the projector and is illuminated by a light source at the position of the camera. The technique can capture subtle illumination effects such as caustics and self-shadowing. Note, for example, how the glass bottle in the primal image (a) appears as the caustic in the dual image (b) and vice-versa. Because we have determined the complete light transport between the projector and camera, it is easy to relight the dual image using a synthetic light source (c) or a light modified by a matte captured later by the same camera (d).

A totally uninformed post! (5, Funny)

Sir_Real (179104) | more than 8 years ago | (#12487156)

Seeing that R-ing the F-ing A is an impossibility for me right now, due to an inexcuseable lack of .torrent or google cache link, I'll just post some outright fabrications about it's content.

This technology proves that there was a third gunman on the grassy knoll. This technique is like what they did in the Matrix, except "backwards." With this technology, any man can find the g-spot. When you look at the videos upside down, you can see into the past.

Re:A totally uninformed post! (5, Funny)

goneutt (694223) | more than 8 years ago | (#12487209)

That post is more relevant than the majority

Re:A totally uninformed post! (1)

vrmlknight (309019) | more than 8 years ago | (#12487465)

as a reply to your sig....
its better to add 0.0.0.0 to your hostfile that way your waiting for 127.0.0.1 to time out, unless your running a web server on your local box.

Re:A totally uninformed post! (2, Insightful)

paulhar (652995) | more than 8 years ago | (#12487218)

Finding the g-spot is quite easy. There is a great book that has pointers...

http://www.amazon.co.uk/exec/obidos/ASIN/189015902 6/qid=1115728290/sr=8-1/ref=sr_8_xs_ap_i1_xgl/026- 2537690-7222055 [amazon.co.uk]

Enjoy :-) [or should I say, let her enjoy?]

crap, you can explain it in a paragraph (-1, Offtopic)

aendeuryu (844048) | more than 8 years ago | (#12487377)

No need to buy anything from Amazon.

Assuming you're fingering the girl, rotate your hand so it's palm up. Then, with the appropriate digit, curl the finger upwards and towards you in a "come hither" kind of motion. Repeat as necessary. On many girls you can actually feel the bundle of nerves as your fingertip strokes over it. This technique will either nail it right on or get you close enough, in which case the girl should be able to talk you through the precise location. Assuming she can talk, that is.

Here's another one for you: At the same time you're doing this, you can actually place the other hand palm down, on the outside below her waist, thereby massaging the g-spot from the outside at the same time. One rave review: "I don't want to know where you learned how to do that."

Here's hoping this turns into the most widely-read -1 Offtopic post ever.

Re:A totally uninformed post! (1)

main() (147152) | more than 8 years ago | (#12487303)

"upside down"... "into the past"...

Laugh? I nearly shat my pants.

Your post is proof positive that Tuesdays are better that Mondays.

slb

Another application (4, Interesting)

Technician (215283) | more than 8 years ago | (#12487192)

With a video projector providing structured illumination, reciprocity permits us to generate pictures from the viewpoint of the projector, even though no camera was present at that location.

Other than using electrons instead of light, that's how a scanning electron microscope works. An object is scanned (raster scan) and one or more sensors near the target pick up the reflections to generate an image. In the SEM the image appears as viewed from the scanning electron beam source.

In the optical one mentioned in the article, the light source is a raster scanning projector which lights a target. The image is produced from photodiodes picking up reflected light.

These two systems are very much alike. One uses photons and the other electrons. The end image is generated the same way.

Military applications? (4, Interesting)

Alizarin Erythrosin (457981) | more than 8 years ago | (#12487202)

Note: I haven't read the paper yet, but it is downloading.

It seems like this might have some military applications as a result. Imagine sticking a photo-resistor array under a door or through a window and then getting "viewpoints" from any of the lights in the room. Could aid in target aquisition and elimination.

Not sure how well it works for something like that, but this is a rather impressive (at least to me) research project.

Re:Military applications? (4, Informative)

Technician (215283) | more than 8 years ago | (#12487299)

It seems like this might have some military applications as a result. Imagine sticking a photo-resistor array under a door or through a window and then getting "viewpoints" from any of the lights in the room. Could aid in target aquisition and elimination.


If you can get to the article, it mentions the light source as a projector. The projector controls the resolution. How it works is a raster scanning video projector lights objects. A photoresistor (in my opinion way too slow. A fast photodiode would be better or photomultiplier tube) picks up the reflected light from the object scanned by the light projector.

A simple street light or the ceiling light in the room will not modulate the light to provide an image signal on a photo sensor slid under a door. On the other hand, if they were doing a video presentation, and the presenter walked between a projector and the screen and you had a photoresistor slid under the door, you would be able to see his arm movements.

You would get the best image when the projector was not showing a slide, but showing a blank screen. Use a CRT projector, not an LCD. LCD's don't raster scan.

Re:Military applications? (1)

banana fiend (611664) | more than 8 years ago | (#12487302)

Noted.

There may be military applications for this - however, this is not magic - you cannot stick a photo-resistor array (or camera) under a door and see behind obstacles.

This is simply a more efficient way of gathering information about a scene. The light source used fot the paper is structured, so unless the people in the room are using some pretty specialist lighting equipment you'll see nothing more than a camera would.

Mirrors (-1, Redundant)

thea64man (850041) | more than 8 years ago | (#12487207)

From now on, BEFORE a website gets slashdotted, someone should create a mirror of it to minimize the /. effect. On the other hand, that mirror would probably crash too. Perhaps a double mirror...

Poor poor servers... (1)

ice666 (601599) | more than 8 years ago | (#12487221)

I always wonder what are the costs associated with a website onces its /.ed? I wonder how many small sites we have taken out and also how much bandwith we spike. Once this is figured out someone should sell /. insurance.

Re:Poor poor servers... (0)

Anonymous Coward | more than 8 years ago | (#12487417)

bah
ive been on apple.slashdot.org two times
my server is a 1.5ghz athlon, and at the time had 128kbits (16k/s) uplink.
I served dynamic php content and got around 50-100hit/s during 10H

I have a chat server(ala irc) running and we occasionned just abit of lag (i do have qos).
of course, pages probably didn't loaded ultra fast for people viewing, but i never went down or refused a client. The page was optimized to a few bytes when slashdot came around however since i had fear my connection would die. (to about 300bytes redirecting to a 100mbit server har har)
Well. I think, if you're not hosting files to download, if your server goes down with slashdot, either you are on 56k, either configuration or site design is plain wrong.
to day i have 1mbit upstream (120k/s) and i wouldn't redirect the page somewhere else. It would just lag a bit, i guess :)

This is cool (-1, Troll)

Spackler (223562) | more than 8 years ago | (#12487244)

It is just like God. You can't actually see it, so just take it on faith that we can see your cards from the light. Let me be the first to holler HOAX, just like God.

Re:This is cool (1)

dim5 (844238) | more than 8 years ago | (#12487301)

Let me be the first to holler HOAX, just like God.

"And then thus spake the Lord, 'Verily I say unto you, HOAX!'"

Re:This is cool (-1)

Anonymous Coward | more than 8 years ago | (#12487331)

Mod this guy up!!!!
hehehehehe.

Re:This is cool (1)

kahei (466208) | more than 8 years ago | (#12487341)


Yeah, right. You expect me to believe there's a so-called 'spackler' somewhere out there? I can't see it. I've never directly observed it. I'm supposed to just accept its existance on faith, based on a few secondary phenomena like a slashdot posting?? Let me be the first to call HOAX!

To find out if I understand this (1)

panurge (573432) | more than 8 years ago | (#12487275)

You can take a picture using an unstructured light source and a structured receiver (e.g. a light bulb and a camera). Or you can use a structured light source (e.g. an LCD projector) and an unstructured light sensor (e.g. a photodiode.)

OK, the stitching together is harder in the latter case, maybe an awful lot harder, but unless I have missed something really big it is a statement of the nearly obvious. Anyone remember the scanning electron microscope? By collecting backscattered electrons, you could use one of those to see around (very small) corners.

Or I am completely wrong and this is something very much more clever. If so, please can someone explain?

Structured light. (4, Informative)

Anonymous Coward | more than 8 years ago | (#12487284)

They make the point that if you illuminate an object with a projector, you can get the image with a photocell. That's because the projector scans the image with a light beam. If you know when you see the reflection, you know where the light beam was when it reflected because you have prior knowledge of the scanning pattern. That technique has been used forever. It's like the flying spot scanners that predate camera tubes.

The 3D part is obtained when you offset the detector and the projector. If I look at a particular point on an object and scan the object with a beam of light, I can get the distance between me and the object as a function of the scanning angle.

Re:Structured light. (4, Informative)

Technician (215283) | more than 8 years ago | (#12487398)

It's like the flying spot scanners that predate camera tubes.


Wow, you remember those?

For those who don't know what they are, it's simply a CRT with a blank raster and a photo detector. Usualy a photomultiplier tube (fast and before photodiodes). The flying spot was simply the bright spot on the CRT. If you put movie film in front of the CRT, the brightness detected by the photodetector was modulated by the film in-between. This was the standard way of showing movies on television in the early days. The flying spot scanner was built into a movie projector with a CRT for the lamp and a photomultiplier tube where the projection lens would go.

In this example, it's a very big flying spot scanner. The lightsource is a projector. (raster scanning light source) The target is a 3D object instead of movie film, and the detector is offset so the 3D object casts shadows to the detector.

The scanned image looks like it would be viewed from the light source with shadows that look like the light source is from the photo detector.

It's all very impressive, but.. (3, Informative)

tonywestonuk (261622) | more than 8 years ago | (#12487287)

... a form of This technique has been done before. Take a bar code for example. A bar code could be read in 2 ways
  • {usual method} laser scans over barcode, light sensor picks up changing intensity of light, as the light is either reflected, or absorbed by the pattern.... or
  • Camera take photo of barcode in one go.

All these people are doing, are using the first barcode technique to, take a picture of the scene. Instead of using a laser, an animation of a moving white dot is sent to the projector. The Camera, is then treated like a light sensor, for each point in the animation, the camera is queried for the brightness of the perhaps, brightest dot in it's field of view. Gradually the picture is built up, pixel by pixel, untill, finally a picture is formed in memory. This picture would be from the perspective of the projector.

Bingo (-1)

Anonymous Coward | more than 8 years ago | (#12487374)

No way

Bang

IANAS, but it looks like reverse 3d rendering... (2, Informative)

capsteve (4595) | more than 8 years ago | (#12487383)

I totally lack any scientific degrees, but this technique looks an awful lot like raytracing in reverse(or even real world application of algebra)... the projector is necessary to help map the way certain areas of the subject react to light based on the surface quality, and using pixel level illumination from the projector recreates the camera... FUCKING BRILLIANT.

this technique works because of the lcd/dlp array in a projector, but i wonder if it can be reproduced if the light source is already a pinpoint(chrismas light, or very small bulb). what happens when the light source is very broad, like that of a computer monitor/ TV? i wonder if this technique could also be used to extrapolate what someone is watching/reading/viewing on screen? taking another stab from a raytracing perspective, i wonder if an environment could be revealed thru image analysis, aka reverse-HDRI?

hats off to the dually photo boys of stanford and cornell... keep up the cool work.

mirror! (1, Insightful)

jazzman75 (637691) | more than 8 years ago | (#12487421)

Someday soon, the owners of a site that gets slashdotted are going to sue faster than CmdrTaco can say "tort reform". It's irresponsible to post, unedited, an article suggesting readers download a 60mb movie without first making some effort to mirror/torrent the file and/or site.

Problem with the video? (1)

iosmart (624285) | more than 8 years ago | (#12487436)

Maybe we should set up this camera technique. We pretend like we're gonna download the file, stick a light source on the side, and TRICK it into getting a copy of the file! ha!

train brain (-1)

Anonymous Coward | more than 8 years ago | (#12487511)

it would be quite handy to train ones brain to do this.

hmmmm, she's cute from this side, wonder what her ass looks like

mirror (0)

Anonymous Coward | more than 8 years ago | (#12487519)

where can I find a mirror to the video (other than the mirrordot site)
or mayeb can somebody send it to me by email? now that I have 2 gigs on gmail i can handle it.
just joking, gmail can't handle attachments larger than 10 megs
but maybe you can cut the whole stuff and send them by email in six pieces.
Send them to cuzuco[at]gmail{dot}com (let's see if you can slashdot my gmail acocunt)
Load More Comments
Slashdot Account

Need an Account?

Forgot your password?

Don't worry, we never post anything without your permission.

Submission Text Formatting Tips

We support a small subset of HTML, namely these tags:

  • b
  • i
  • p
  • br
  • a
  • ol
  • ul
  • li
  • dl
  • dt
  • dd
  • em
  • strong
  • tt
  • blockquote
  • div
  • quote
  • ecode

"ecode" can be used for code snippets, for example:

<ecode>    while(1) { do_something(); } </ecode>
Sign up for Slashdot Newsletters
Create a Slashdot Account

Loading...