• Wondering which camera, gear, computer, or software to buy? Ask in our Gear Guide.

Dual Photography

Zensteve

Zensteve

Okies... this is going to blow your mind. :cool:

Here is the original link.

Original video link on above page... re-hosted here >> Dual Photography << (60MB, mp4)

Now... the text below may sound really bizarre. If you didn't fully understand it (like me), watch the video and all makes sense.

Anyone have predictions on how MUCH this will change the shape of filmmaking? :idea:

The rest of the article (and further stuff, as well as researchers' credits etc) are in the link to the source.
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.
Click to expand...
 
Last edited:
Sort by date Sort by votes
Wow.
I am envious of those brains! This is really cool! My mind has been blown.
I can see the applications now!
Special Lighting in post!! No more need for lights... all you'll need are projectors! Ha!
Incredible.
 
Upvote 0 Downvote
Seriously, I understand the concept, just not the execution of it.
Click to expand...

Same here.

What I can't get my head round is why they are using a projector? If it's just a straight maths/physics thing then it shouldn't it work with any light source? If, however, they are scanning the pixels from the projector, then surely they've just found a very, very complicated way of turn a $800 projector into a very poor digital stills camera.

I'm sure that this is just a reflection of my profound ignorance and if I was a lot smarter I'd see the potential in this.

I tell you what though, the brown bear in the video is a natural, I'd work with him anytime.

Even so Mr Zen you have, once more, found a profoundly interesting piece of information. I shall meditate on this.
 
Upvote 0 Downvote
Very interesting... especially the last bit about the playing card.. I can see how something like that might be useful for police and whatnot.. but it seems you have to use the projector as an illuminator, so that you can scan specific pixels at a time, so without a projector illuminating the scene it would appear that it's worthless. ;)
 
Upvote 0 Downvote
is this (in general) the same as me reversing my headset speaker and mic jack and talking into my speakers and then reverse them back and hearing a very poor static quality of my voice? or is way way beyond that. if you can use a projector as a camera to, *Scan ?* a scene then I suppose you can use a camera to project?


Im totally lost.
 
Upvote 0 Downvote
way different

essentially it's using the same technology as ray tracing (think Maya or Lightwave) but using a real life scene to generate the computer generated scene. By scanning the light intensity levels in a specific way, it can generate the scene as it would be seen if the camera and projector (light source) positions were switched.. the most impressive example is in their demonstation video.. the very last part with the playing card. in the initial camera angle, you see the back of the card, in the generated image, you see the face value of the card. it's truly amazing!
 
Upvote 0 Downvote
You must log in or register to reply here.
Back
Top