A Single Pixel Camera 190
BuzzSkyline writes "Scientists at Rice University have developed a one pixel camera. Instead of recording an image point by point, it records the brightness of the light reflected from an array of movable micromirrors. Each configuration of the mirrors encodes some information about the scene, which the pixel collects as a single number. The camera produces a picture by psuedorandomly switching the mirrors and measuring the result several thousand times. Unlike megapixel cameras that record millions of pieces of data and then compress the information to keep file sizes down, the single pixel camera compresses the data first and records only the compact information. The experimental version is slow and the image quality is rough, but the technique may lead to single-pixel cameras that use detectors that can collect images outside the visible range, multi-pixel cameras that get by with much smaller imaging arrays, or possibly even megapixel cameras that provide gigapixel resolution. The researchers described their research on October 11 at the Optical Society of America's Frontiers in Optics meeting in Rochester, NY."
I don't get it... (Score:3, Interesting)
Re:I don't get it... (Score:5, Funny)
modify parentificator upwardly (Score:3, Funny)
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That's vive la différence. Difference is a girl in French. :)
No real French speaker would make this kind of mistake...
There's the question... (Score:5, Insightful)
Also, what degree of photon loss do you have from the arrays? No mirror is perfect...
Re:There's the question... (Score:5, Informative)
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Actually, a glass mirror is a poor example. Ever look at a reflection within a reflection etc in a glass mirror? Eventually goes dark because the light is passing through the imperfectly clear glass and then back through it again on each reflection.
On the other hand, a reflector telescope with a thin (few molecules) layer of aluminum on *top* of the mirror has some crazy 99.9% reflectivity (sorry, too lazy to google th
Re:There's the question... (Score:5, Informative)
Not likely. And it certainly doesn't sound mechanically robust to have moving parts replace a purely electronic chip. Cameras need to be rugged.
Also, what degree of photon loss do you have from the arrays? No mirror is perfect...
Imperfection in the reflectivity is probably secondary to diffraction, which will be a big problem for these small mirrors - and they would have to shrink even further for reasonable (multi-Mpixel) image resolutions. Diffraction is the biggest limiting factor for contrast in DMD projectors.
There are other problems with this design. First off, it is a time-sequential acquisition. The reconstruction algorithm assumes that all measurements are taken from the exact same scene. God knows what garbage it produces if you have moving objects or camera shake.
I guess their biggest motivation is to do the image sensing directly in compression space. Unfortunately, their compression space is vastly inferior to the compression space of, say JPEG. You see, JPEG is very cleverly designed in that it doesn't actually zero out certain frequencies directly - it just quantizes higher frequencies more agressively than lower ones, and that results in data that compresses better with a lossless compression algorithm (Huffman). By contrast, this compressive camera thing essentially directly zeroes out certain frequencies that have low amplitude. Not a very good idea perceptually.
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The problem with CCDs is you need to clock the values off the capacitors. Either you use a machanical shutter to stop smearing while you do this, or clock it into masked areas, which means you either need to accept a 50% loss of area, or have micro-lenses, etc.
With the single pixel idea you shouldn't have too many problems if you can clock the system fast enough.
It also may be possible to create an array of mirrors with better behavioural uniformity than an array of detectors.
D
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The idea behind the average consumer camera is to gather photons from a large area in a reasonably short amount of time. Usually we do this with film or with a CCD or CMOS array. However, film is going out of vogue, and CCDs and CMOS arrays can have dead spots. From a scientific standpoint, arrays are problematic for this very reason... plus, who has time to calibrate several thousand detector elements per camer
101 (Score:5, Funny)
Re:101 (Score:5, Funny)
Please take another photo and maybe the randomness of the process will enlighten us.
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Re:101 (Score:5, Funny)
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and what 1 is naked
I think you mean which, not what. Sorry, sometimes I just can't resist my primal grammar nazi instinct.
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Applications (Score:3, Interesting)
Re:Applications (Score:5, Insightful)
This is unlikely for several reasons 1) resolution is far more limited by optical aperture than by the CCD array, 2) the system reads its images over a longish span of time - not good when your target is passing rapidly beneath you, and 3) the system requires considerable postprocessing - this either means you have to slow down the rate at which you take pictures, or eat scarce communications bandwidth.
The same objections apply to both applications.
Already done better in 1999 (Score:5, Informative)
Instead of using micro mirrors, the Los alamos team used an LCD which were more mature at the time. And Instead of using random modulation they used a progression of zenike polynomials and thus achieved much more control over the data compression.
patented too (Score:5, Informative)
Re:Already done better in 1999 (Score:5, Funny)
http://www.rit.edu/~andpph/text-demo-scanner-cam.
Should give you an idea of how to do it yourself to get gigapixel sized pictures.
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Re:Applications (Score:5, Informative)
"Superresolution image processing is a computational method for improving image resolution by a factor of n[1/2] by combining n independent images. This technique was used on Pathfinder to obtain better resolved images of Martian surface features."
Taken from the abstract of this article [inist.fr]:
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Re:Applications (Score:5, Interesting)
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that's one big pixel (Score:5, Funny)
The camera's one pixel, but when you print it out full size, you get a mega pixel.
photo album (Score:5, Funny)
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Not for me. I have ClearTypeTM on!!
Had to be said... (Score:5, Funny)
Hold still, dammit!!! (Score:5, Funny)
Voyager worked (still works?) like that (Score:5, Interesting)
Early fax machines worked the same way, but spun the paper around while the single photocell moved linearly left to right.
Hmmfff - Guess I'm giving my age away...
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IANAE (an engineer) but I don't know if moving parts in a camera that's going to jiggle around anyway is such a good idea. At certain resolutions would you end up with the sum of the human factor's jiggles - plus the movement of the innards - distorting the picture even worse than today's cameras?
Re:Voyager worked (still works?) like that (Score:5, Interesting)
Hmmfff - Guess I'm giving my age away...
You should, in fact, call the Guinness Book of Records, as you must be the oldest person in the world. Fax machines of some sort or another have existed since the mid-late 19th century. [wikipedia.org]
Mars Viking lander (Score:2, Interesting)
First IR Detectors (Score:2)
The first IR astronomy imagers worked like that as well. With a single pixel. In fact, just last year I was in a class where we made a radio map of the sun using a single pixel (dish) radio telescope.
The sounds like just a different way to do the same thing people have been doing for 30+ years..
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Low-orbit weather satellites [noaa.gov] work this way too. They have a rotating mirror [noaa.gov] that scans the image on to a single-pixel sensor, then the spacecraft's motion provides the Y dimension. These things take really cool pictures. I use a modified Radio Shack scanner and my computer (with its sound card) to receive them.
I've toyed with mechanical scanning for a couple of applications: making a high speed camera, and turning a
Nothing for nothing (Score:5, Insightful)
If you record things "pseudo-randomly", it'll be harder to get a predictable result
If you record a billion pixels instead of a million, you'll need to store them.
If you reduce the number of pixels, you reduce your redundancy.
It's still an interesting idea and probably has some specialist applications that will be very practical. But don't look for this in your Nikon or Canon camera in the next 10 years. Not sure what they are but if it can be made small enough I imagine a gigapixel camera on a space probe or better yet a space telescope (which can have more time to collect data) might be one. Of course it could also end up useless. That doesn't mean the technology shouldn't be explored. You never know what's going to provide the next breakthrough in understanding or application.
Re:Nothing for nothing (Score:5, Interesting)
What they are recording is not solely a pixel, I would suspect, but the configuration of mirrors that achieved that point. So, there is a significant amount of information that they can extrapolate from just a random number seed and the final color. The plenoptic function that describes the transfer of light from the environment to the plane of the sensor is 4D. By capturing from many different non-parallel input rays onto a sensor, you can extrapolate a lot about the environment that isn't present in a purely parallel data set.
What I suspect they're goal is, is ultimately getting an array of mirrors onto a consumer-grade camera, and having it take three or four shots in rapid succession, then merge the information gained from each so that the result is more like having a High Dynamic Range image (well beyond the capabilities of any consumer-grade sensor) and use a tone-mapping algorithm to bring it back into a typical 8-bit range per component. It's complicated, but not impossible. Similar such things that are only a year or two old in the graphics community (flash + non-flash images being merged to give good color in low-light situations, multiple exposure images merged for HDR, etc) should come out in a couple of years as automatic modes for color correction, probably even on low-end cameras.
Of course, I still have a 6 year old point and shoot, so what do I know?
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Consumer level cameras don't need an automatic HDR mode until well after they include RAW support. No point in going for 32-bits when you're only using eight of the twelve you've already got.
Anyway, from the grandparent:
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Odd you'd say that, considering how much computer technology presently relies on the inherent predictability of pseudorandom algorithms.
Ever called srand() or randseed() ?
Other wavelengths (Score:5, Interesting)
Re:Other wavelengths (Score:5, Interesting)
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Radio waves have large wavelengths and so your resolution is very restricted. Taking pictures of anything that's not a long distance away will give you pretty much the result above.
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60Hz wiring would be so fuzzy as to be useless... but what if you plugged in a little gizmo that put a nice high-freqency signal on the line? That could actually be useful, though it'll be a long time before something like that's practical or remotely cost-e
Oh yeah, that's right... (Score:2)
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Radiowaves are big and they go through just about everything.
They don't go THROUGH anything at all (at least nothing conductive). It would be more accurate to say they go AROUND things, but that's not really correct either. It's really a matter of scattering and interference. And they DO interact with things -- your car's radio antenna is not particularly substantial and yet it picks up radio waves.
In general, a wave will reflect from a conductive surface that is much larger than its wavelength, it wi
any astronomy (Score:3, Interesting)
slow shutter much? (Score:2, Interesting)
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Do not underestimate the power of our shiny disco ball.
Oh, come on! This has been known for ages! (Score:2, Interesting)
can't wait (Score:5, Funny)
Resolution? (Score:3, Funny)
Now THERE'S a reality show we need (Score:4, Funny)
I'm envisioning a sticker on the box that reads "THE ONLY MICRO-MEGAPIXEL CAMERA!"
So this is a reverse CRT... (Score:2, Insightful)
exotic sensors (Score:3, Insightful)
Coming Soon (Score:2, Funny)
The point is focus and low light capability (Score:5, Informative)
The technique in use for years for infra-red cameras involves the use of a single (Peltier-cooled) pixel and a scanner, but scanners have numerous problems one of which is that there is always vibration caused by the two frequency components of the line end switching of the horizontal and vertical scans. This technique, by using pseudo-random switching, should eliminate vibration.
So the ultimate long term goal would appear to be the ability to produce 3-D images with focus throughout the entire scene, low light capability and an absence of blur due to vibration. IANAOR (I am not an optical researcher) but it seems a good line of investigation.
Oh dear, abuse (Score:5, Informative)
Like a lot of people who do not know any optics, I suspect you think that the light at the scene is somehow concentrated by the lens to form the image. It isn't; the lens doesn't suck in any extra light other than what impinges on it.
A single pixel is effectively approx f/1.
Oh yes, and you are arrogant, rude, and stupid. Perhaps you really do have a job with Microsoft.
it's probably been said.. (Score:5, Funny)
Practical uses. Why the stupid comments? (Score:5, Interesting)
If you are interested you can find out a lot about the really fascinating and cutting edge science of computationally assisted optics, or whatever is the correct term. It is the same field as the people who have been experimenting with giant arrays of cheap cameras, capturing entire light fields that can be sliced in time and space and reprojected later on, etc. It is computers plus physics and a big dose of creativity, which is why it is related to SIGGRAPH too.
Anyway this is interesting and is based on different principles from current megapixel cameras, which is why they think it might improve current cameras too. Just like the way the spaghetti physicists were laughed at by Harvard's igNobel, even though they finally solved something Feynman couldn't crack and have discovered a new method for focusing energy.
Just off-hand, the one pixel camera and compressive imaging theory they have looks very interesting:
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Spam (Score:3, Funny)
The only thing I care about.... (Score:2)
Some advantages (Score:2, Insightful)
moving parts? power and reliability (Score:2, Insightful)
With all the moving parts, how much power does this array consume? What happens if one of the actuators sticks: do you get dead pixel effects?
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The durability of a micromirror array is actually very high. It's counterintuitive, but not hard to understand. The reason is the mirrors are so tiny. They have very little mass which means they transfer very little stress to their mechanical structure, even under large G forc
Random sampling vs compression (Score:4, Insightful)
It seems to me you need to assemble the image before you can decide what to throw away.
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JPEG 2000 uses a wavelet matrix, which could be simplified and explained as it would operate on a 2-pixel image. Instead of storing 2 pixel values, you can store the average of the 2 pixels, and the difference between the 2 pixels. That is equivalent. Now you can store the average with high precision, and the difference wi
Dual Photography (Score:2)
This will be the perfect companion for my... (Score:2, Funny)
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here we go again (Score:3, Informative)
However, there's a reason we "acquire first, ask questions later", as the article talks about current systems: electronics is much better at "asking questions" than mechanical hardware.
Narrow-bandwidth Television Association (Score:2)
"Mechanical scanning devices which can be used include the Nipkow disc (shown above), the drum, the mirror drum, the mirror screw, oscillating mirrors and combinations of these. The camera usually has a lens to form an image which is then scanned and the light passes through to a photocell which generates the electrical signal" - Narrow-bandwidth Television Association [wyenet.co.uk]
Part Number (Score:3, Insightful)
Useless (Score:2)
3-d imaging (Score:2)
It's called a flying spot- (Score:2)
Seriously, this is a well known technique. We used to use it to scan large areas of highly variable terrain- the only novelty is the addition of mirrors and the fact that it's 100x faster than in the past.
The Hadamard Transform and Multiplexing Advantage (Score:2)
1) In spectroscopy, we have the idea of a multiplexing advantage. This is the increase in signal to noise which occurs from measuring the same information multiple time via its inclusion in a convolution of signals which is later
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not patentable, prior art exists (Score:3, Informative)
it was very difficult to make a working early camera tube with lame phosphors, flaky passive components, and nightmare wiring. but it was pretty simple to paint a raster on a screen by comparison. so the object to be scanned was put in front of the raster and a single photodiode vacuum tube picked up the changes in brightness, and modulated the "spot" created by the line and position sweep signals.
old hat by the end of the 1920s, but used as late as the 1980s in super-quaity scanners to encode 35mm and 16mm film for network-quality television. the indian-head generators that took two racks of tubes, and provided the best signal reference at the start of a broadcast day and the best calibration signal for TV repairmen in the field, were all flying-spot scanners.
no patent forrrrr YOU.
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Saying that this is the same thing is like saying that optical media (CD et al) are just another form of vinyl record. The principle's somewhat different, even if the method has similarities.
m-
Its a lie (Score:2)
Marketing (Score:2)
I forsee some marketing problems with this technology.
Customer: How many megapixels is it?
Salesman: 0.000001!!
Very much like the "1-bit DAC" trend for CDs (Score:2)
Check out my own single pixel camera (Score:3, Interesting)
They are starting to get smarter... (Score:2)
It occurs to me that if you stuck a camera out the window of a moving car driving down the street you have enough information to make an awesom 3-d panarama of that street (3-d because the moving view gives you the same effect as multiple came
Steve Ciarcia (Score:2)
Re:Non-static images (Score:4, Informative)
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