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New Technique Creates 3D Images Through a Single Lens
Zothecula writes "A team at the Harvard School of Engineering and Applied Sciences (SEAS) has come up with a promising new way to create 3D images from a stationary camera or microscope with a single lens. Rather than expensive hardware, the technique uses a mathematical model to generate images with depth and could find use in a wide range of applications, from creating more compelling microscopy imaging to a more immersive experience in movie theaters."
"Harvard researchers have found a way to create 3D images by juxtaposing two images taken from the same angle but with different focus depths"
You might not care about that, but I personally care more about the crap they show on screen. As long as what they're showing was shot in 2D and turned into 3D using computer manipulation, I'm not interested.
From the sound of this, they can use one lens to create an image that's effectively 3D and do so for the entire scene, rather than portions. That I'd consider seeing.
When they get that down, then worrying about the eye wear will make some sense. At this point the 3D just isn't good enough in most cases to waste money viewing it.
If you need special eye wear or need to stand in a certain position, it's not 3D, merely stereo.
No, that's 3D, 3D is when the eyes see slightly differing images and interpret that as a scene with depth.
The definition you're using is highly non-standard and completely misses the point. A movie will always require that you be sitting in the right place. Just as one doesn't typically watch a Broadway play from backstage. Or aren't those plays 3D?
Having two lenses is not a requirement to capture stereoscopic images. It can be done with a single (big) lens, and two slightly different sensor locations. But you're limited by the distance between those two sensors, and a single large lens isn't necessarily cheaper or easier to use than two smaller ones.
What this system does is use the out-of-focus areas as a sort of "displaced" sensor - like moving the sensor within a small circle, still inside the projection cone of the lens - and therefore simulating two (or more) images captured at the edges of the lens.
But, unless the lens is wider than the distance between two eyes, you can't really use this to create realistic stereoscopic images at a macroscopic scale. The information is simply not there. Even if you can extract accurate depth information, that is not quite the same as 3D. A Z-buffer is not a 3D scene; it's not sufficient for functional stereoscopy.
Microscopy is a different matter. In fact, there are already several stereoscopic microscopes and endoscopes that use a single lens to capture two images (with offset sensors). Since the subject is very small, the parallax difference between the two images can be narrower than the width of the lens and still produce a good 3D effect. Scaling that up to macroscopic photography would require lenses wider than a human head.
The result does not impress me too.
You can do TRUE 3D through a lens because you can get depth from interferences of the input light field over the finite aperture (\approx lens) size. That requires only A SINGLE IMAGE.
One example of this method is the Double Helix Point Spread Function (DHPSF) developed at Univ of Colorado by Pr. Piestun from a specific phase-mask :
http://3.bp.blogspot.com/-oX6BL98Bi8Y/TvstLYSp5jI/AAAAAAAABLI/fDKeFKvKWs0/s400/MS+Double-Helix+PSF.JPG
If you have the angle, you will have a measure of the depth. This estimation requires only one image. And this is more than ten years older.
The irony of Lytro is that people fail to realize that depth of field is inherently a function of resolving power. When Lytro destroys resolving power to create alterable depth of field in post, all they are really doing is creating a means of artificially limiting depth of field, not a means of enhancing it in. With sufficiently good techniques for simulating OOF areas and image reduction the same ability could be offered without the immense penalties and with conventional optics (except no one would want it, just like Lytro). Lytro is truly the emperor's new clothes.
Lytro is a colossal waste of VC funding.
It is a cool idea but they are rotating the "3D" image about 1 degree. If they had even halfway good 3D data they could have rotated a whole lot more. My guess is that after 1 degree their "3D" turns into a spiky mess. Man I am getting sick of this popular science news, "Science has way to make flying cars a reality in 5 years."
I am not doubting that 3D information can be extracted from focal data, I am doubting that these guys can do it.
I've done some quick research into what you suggest:
http://www.stanford.edu/group/moerner/sms_3Dsmacm.html
Basically you need a lot more than a single 2D image. You need a stack, and from the stack you can measure the angle you suggest. Your very own link illustrates this. What this technique allows you to do is to measure depth of point-like objects to a very good resolution, better that can be usually done with confocal imaging, but this is not easily applicable to other modalities.
I think you might be confused because in confocal microscopy, a "single image" is a 3D stack of optical sections.
Also you need to insert a phase mask into the focal plane of the optical equipment. This is not easily done.
Basically the author's technique referenced here is applicable to a different field of modalities, so it is differently useful.
Cheers.
Sorry, with the clicky:
non-paywalled version of the article.