Refocusable Plenoptic Light-Field Photography

virgil_disgr4ce writes "Wired is reporting that a Stanford student using about 90,000 microlenses has developed a plenoptic camera whose images can be refocused, via software, after they are exposed." From the article: "'We just think it'll lead to better cameras that make it easier to take pictures that are in focus and look good,' said Ng's adviser, Stanford computer science professor Pat Hanrahan."

Comments

innovation

[Lord Ender]

As soon as I heard of this, I immediately realized how to do it. But I would not have thought to do it on my own. This kind of smart thinking is why we have a patent system. The patent system was not designed to protect business methods, such as completing a sale using n clicks instead of n+1.

Re:innovation

[Anonymous Coward]

To the contrary, this kind of smart thinking is exactly why we don't need a patent system. Did this guy get a patent? No! Patent rights are not what is motivating him at all. Furthermore, this guy didn't invent this idea. Practically no worthwhile invention is invented out of the blue by a single person, at least not any more. People have been researching this for years. Building on the accomplishments of previous experiments, publishing their results in peer-reviewed journals, that sort of thing. The only thing patents could have done to the development of this technology was obstruct it. Luckily that doesn't seem to have happened.

Re:It's fun.

[mabinogi]

More to the point - what we see with one eye.

With two eyes you can already see the effect - holding a hand in front of your face doesn't stop you seeing what's behind it until you completely cover both eyes, etc.

Getting the least out of your 16MB camera

[Tsar]

Yes, the plenoptic camera has some neat benefits, including the ability to reconstruct the field of view from the perspective of any point on its objective lens. But for the image to contain all that information, it by necessity does NOT contain information that it otherwise would--in this case, resolution.

Look at the sample images. Even the sharpest-focused regions are soft-focused. This is a 16-megapixel camera with an effective resolution less than 1/3 that of VGA. Granted, the images can be refocused and depth information can be extracted, but do you really want to have to buy a 188-megapixel plenoptic camera to get sharp 1-megapixel images? Is focusing really that hard?

Re:Getting the least out of your 16MB camera

[jettoblack]

I don't think this technology will ever be useful to typical snapshooters or photographers. For the former, just stick an f16 lens on a small-sensor digicam and you'll have near-infinite DOF for most shots, and the latter generally prefer narrow DOF and know where they will be focusing before pressing the shutter.

However, I imagine this might be useful for some kinds of analysis photography, especially when dealing with high-speed motion. Those kinds of shots usually require a large aperture to gather enough light (due to the very high shutter speed), meaning a very narrow DOF. If you're shooting something which is very expensive or happens only once (say, explosion anaylsis, freezing bullet-time action, etc.) and getting the right focus or wide DOF is critical, this could be very useful.

Re:Getting the least out of your 16MB camera

[ozzee]

I suspect that there is now use for that 300-megapixel sensor.

Considering that we already have gigabit memory chips, I can see that it's plausible to have gigapixel light sensors (sometime in the future).

Given that 4 (good looking - low noise) megapixels would satisfy most non-professional type photographers, I think this is not that unreasonable to sacrifice pixel count for ease of use.

Re:Getting the least out of your 16MB camera

[Viceice]

You obviously aren't a photographer. Many award winning shots are accidents. Taken during such times where, for example, a photographer is running for his life in a hail of bullets, simply pressing the shutter as he runs, not even looking in the viewfinder.

What I'm getting at is, some moments happen in literally in the blink of an eye and they only happen once in a lifetime. So in that split second where you are trying to take a shot and have no time to double check, won't you be sorely disappointed if your ticket to a Pulitzer was ruined by the wrong f-stop setting? Or the wrong focus?

Back in the day of 8mb CF cards, a 6megapixel 6mb RAW was insane. But in this day of 4GB CF and memory prices what they are, 6 or even 16 mb RAWs are but a drop in the bucket. Heck even with today's memory capacities, if you had a camera that produced a 188mb RAW, it'd still be perfectly acceptable to any photographer, considering the possibilities for photography this new technology gives you.

So much for thinking 32MB was decent storage.

[illumina us]

From the looks of it, this takes hundreds of images and stores them in one file. Then uses software to create a single, desired, image. This means that conventional storage will no longer be enough, for while one image now takes up several hundred kilobytes to a couple megabytes (JPEG compression), this new method will take up hundreds times that size. >.

Re:You don't really lose resolution

[(negative video)]

The best way to think of it is take a standard good quality camera with big pixels, subdivide each pixel into a grid of 12x12 or so tiny pixels - more like the size of pixels in cell phone cameras - and put a microlens over it. You get ... roughly the same noise characteristics, ...

The space between the pixels tends to be hard to shrink, so as you add pixels an ever-increasing fraction of the image sensor tends to become dead zones. Using Foveon-style stacked detectors instead of a filter mosaic would, of course, help quite a bit.

A question: can you refocus colors independently to correct chromatic abberation of the lens?

Idea has no practical application!

[Crspe]

I saw this article about a week back. I am quite sure that this will never see a practical application ... They take a 16MP input image to produce a 0.08MP output image!!! They are using a $15000 camera system to produce images one quarter the size of VGA!!! Say what you want, but there are better ways to improve DOF.

They reduce resolution by a factor of 180, but only improve depth-of-field by a factor 7. This is particularly silly because the only reason they have a bad depth-of-field is because they are using a huge expensive sensor. If they would switch to a small cheap sensor like you find in any cheap digicam (1/1.8"), they would get the same improvement, and save $14800.

The light-performace of this small sensor would be just as good as their large one - if you use the same huge pixels that they do (to produce a 0.08MP image), you will get the same low light performance.

If you want more details on why this idea has no use, check out this thread:
http://luminous-landscape.com/forum/index.php?show topic=9354

Interesting article, no practical application.

Re:A blanket solution.

[HuguesT]

Except real-world pinhole cameras are always blurry instead of always sharp...

This is due to the fact that the pictures sharpen as the size of the hole diminishes (i.e. large hole = very blurry, small hole = less blurry), but there is a limit to how small the hole can be until it becomes counter-productive due to diffraction.