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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."
Better Porn!
sigfault. core dumped.
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.
A slashdotter who didn't build his own computer is like a Jedi who didn't build his own lightsaber.
http://graphics.stanford.edu/projects/lightfield/ If you've attended siggraph for the last 8 or 9 years you yawn with me.
I'm curious... how adjustable is the post-processing focusing? E.g. depth of field, f/stop, etc. Do you basically get to adjust ANY of that after the image is recorded?
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I wonder if the image data gathered by such a camera could somehow be transformed into basic 3d depth information. If so, this could be the beginning of 3D imaging for the consumer.
This is great technology but the author of the article used an incorrect title. Blurry photos are almost always caused by camera shake, not focusing on the wrong subject in a depth of field situation.
This technology doesn't do anything to prevent camera shake. Most modern cameras are extremely good at autofocusing on the correct subject in a short depth of field situation. The camera designed by the Stanford guys is an amazing invention and will revolutionize action, sport, and scientific photography (especially at the macro level) but it will do nothing special for the consumer who simply doesn't understand that the longer the exposure the more likely the blur from camera shake.
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Having seen this stuff in action first hand, it's cool as heck. Also a tad scary. Miniblinds not closed 100% then you can see in, tree in the way no problem.
Basically what we see as solid with 2 eyes, may not be solid at all. So much like the IR/UV cameras, this new toy has a dark side.
- Adam L. Beberg - The Cosm Project - http://www.mithral.com/
Have you seen how in movies and TV they can zoom and then sharpen any image using software? We'll it seems that technology is finally comming to real life!
please excuse my apathy
I can make up really technical sounding names, too!
I am scientifically inaccurate.
Countdown until you hear about someone using one on CSI: 5... 4... 3...
I am scientifically inaccurate.
The linked article comments that there's an effective loss of resolution, but goes no further.
Obviously taking a camera that's designed to record light intensity and modifying it to record light intensity and direction isn't free. In the worst case, you're decreasing your effective resolution by the number of new lenses, or by a factor of 90,000. I don't think that's quite what happens though, because many of these lenses will be recording essentially the same information, and while only one may be perfectly focussed on part of the frame, nearby lenses can probably contribute color and intensity information as well. If we assume a 2Mpixel image is "good", the article's comment that the student's using a 16Mpixel camera but that an 8Mpixel camera might be good enough seems to support a roughly 4x to 8x decrease in effective resolution. Can the poster who claims to have heard the actual discussion at Siggraph comment?
That's a high price to pay for not having to use the viewfinder. It's cool tech, and I'm sure there are practical uses for it somewhere, but I don't think consumer cameras are the place for it just yet.
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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?
The more potential focal points you want, the less resolution you can have for any particular one of them. You have to record information for all possible focal points on the CCD. Conceptually it's no different from, say, dividing the CCD into four parts and recording an image with a different focal point on each of the quarters, then post processing to combine them as required. I think. So photographically speaking the image is degraded compared to just getting the focal point right in the first place. Which isn't to say there aren't cool things you can do with it.
I'm not wrong. You haven't thought about it hard enough.
http://en.wikipedia.org/wiki/The_Endochronic_Prop
This will not only ensure that your photo of Auntie May is in focus, but the camera will make sure that the image is captured at a time when her eyes are open and she's smiling.
The next step is to pair the cameras and the LED image emitters, similar to night-vision goggles, to make a really kewl pair of corrective lenses. Truly the ultimate nerdwear!
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using about 90,000 microlenses
Patents brought to you by the fly people.
Table-ized A.I.
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. >.
-illumina+us "I put on my robe and wizard hat..."
You could always go to a pin hole camera and eliminate the problem entirely. Alright so you'd need 10,000 ASA film or .1 lux for video but focas would never be an issue. Always been a massive fan of pin hole cameras. It's also a handy trick for those of us with failing eyesight for reading fine print. There have also been lensless cameras that use a rotating slit. There are 360 cameras that use the principal. Fun with optics
Sounds like this is a popularized writeup about the work that was just published at SIGGRAPH in July. So it's more recent than 1996.
By the way, in case somebody doubts this, I did this in 1996 and used my mac laptop to compute the refocused image. I was experimenting with imaging from earth imaging sattelites. I still have the code, which actually was a relatively slow script written in Igor Pro.
Some drink at the fountain of knowledge. Others just gargle.
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 the same spatial resolution as the good camera, roughly the same noise characteristics, and the ability to refocus and pull other light field tricks like hitchcock zooms.
You just have to be aware that treating the data as a light field it's very noisy, like a crappy cell phone camera, but when you add up pixels to make a focused image, the noise drops back to regular good camera levels.
It's just harder to deal with the amount of data you get off a large sensor with tiny pixels, and they're also harder to build, but neither point is a showstopper and these are mere engineering issues...
Bullet time? That's what they liked to call it. The reason being, a bunch of cameras would be placed where the motion was to go. Then, a long unbroken string would be attached and run through the trigger of each camera. The other end of the string would be attached to a subsonic bullet, hence "Bullet Time." When the moment came, the bullet would be fired, triggering the cameras in sequence. The "Bullet Time" sequence gunmen would attempt to kill the directors as they fired, but failed miserably, hitting instead the story and script-writers, resulting in two miserable sequels.
Consciousness is a myth. Trust me.
Could this be used to sharpen what we see in an x-ray image of a person? Take an x-ray of the whole body and then refocus to concentrate on one particular cross-sectional plane?
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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.
w topic=9354
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?sho
Interesting article, no practical application.