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Digital Photos Give Away a Camera's Make and Model 260

Posted by kdawson
from the nobody-saw-me-you-can't-prove-anything dept.
holy_calamity writes "Engineers at Polytechnic University Brooklyn have discovered that digital snaps shorn of any metadata still reveal the make and model of camera used to take them. It is possible to work backwards from the relationships of neighboring pixel values in a shot to identify the model-specific demosaicing algorithm that combines red, green, and blue pixels on the sensor into color image pixels. Forensics teams are already licking their chops."
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Digital Photos Give Away a Camera's Make and Model

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  • stretch? (Score:5, Interesting)

    by Speare (84249) on Monday November 17, 2008 @11:01PM (#25796713) Homepage Journal
    As even the cellphones are producing 3 megapixel images now, very few people need to be passing full-resolution originals around. If you scale the image down to a screen-usable 1 megapixel image, there's not going to be a lot of bayer mosaicking information still available.
    • Re:stretch? (Score:5, Funny)

      by narcberry (1328009) on Monday November 17, 2008 @11:35PM (#25796987) Journal

      Maybe so, but you still have the full size images on the camera. If someone were to get a hold of that they would be able to tell what camera took the images after a few weeks of intensive forensic study.

    • Re:stretch? (Score:5, Insightful)

      by trum4n (982031) on Monday November 17, 2008 @11:45PM (#25797093)
      Feed your RAW images to photoshop, then hit NTSC color mode, then compress to jpeg. All their secret information is gone forever. Only idiots would let this work. and oh yea, those idiots didn't delete the Meta-Data anyway, cause they dont even know what it is.
    • Re:stretch? (Score:4, Insightful)

      by lysergic.acid (845423) on Tuesday November 18, 2008 @12:49AM (#25797637) Homepage

      or you could just use a camera with a Foveon X3 sensor [wikipedia.org]. there's no demosaicing involved since it employs 3 vertically stacked photodiodes (red, green, blue) at each pixel sensor to capture color information.

      here [wikipedia.org] is a diagram showing how a multijunction photosensor works. unlike bayer filter sensors, Foveon X3 sensors produce no color artifacts.

      • Re:stretch? (Score:4, Insightful)

        by Tinik (601154) on Tuesday November 18, 2008 @01:12AM (#25797807)
        But then wouldn't the lack of demosaicing itself be the tell-tale sign that it was taken with a Foveon X3 sensor?
        • Re:stretch? (Score:4, Insightful)

          by the_womble (580291) on Tuesday November 18, 2008 @03:55AM (#25798785) Homepage Journal
          It does, but rather than narrowing it down to a particular model, it narrows it down to any digital SLR (and maybe other types) camera made by Sigma.

          Add to that the fact that reducing the image size will probably get rid of the evidence, using a raw image and demosaicing on a PC will tell you what software was used instead of what camera was used, there are a lot of limitations.

          On the other hand, most people do not know all this - then again, most people are unlikely to think of deleting the meta-data either.

          • Re: (Score:3, Insightful)

            by moonbender (547943)

            It does, but rather than narrowing it down to a particular model, it narrows it down to any digital SLR (and maybe other types) camera made by Sigma.

            Given how few Sigma cameras are sold compared to any popular model by the big manufacturers, that isn't say much, right? At the moment, anyway.

      • Re:stretch? (Score:5, Funny)

        by cunniff (264218) on Tuesday November 18, 2008 @01:22AM (#25797887) Homepage

        Eric: Horatio, there does not look like there is any mosaicing information in this image.
        Horatio: Eric, that means the image was taken with a camera with a Foveon X3 sensor.
        Cally: Zeroing in on professional camera stores... I have an address
        Horatio (menacingly): Eric, get on it.

        Where's my CSI: Miami royalty check?

    • by wvmarle (1070040)

      Sure... but how many people are really doing that?

      I get more and more complaints that e-mails bounce: my mail server has a 10 MB per-email limit, and that should be enough. But many people copy the image from the camera, and then directly attach it to the e-mail. So I get many 3-4 MB sized attachments!

      It really seems most people just don't care or don't know about this.

  • by Chirs (87576) on Monday November 17, 2008 @11:01PM (#25796715)

    Quite often there are different manufacturers using the same sensor. Since this locks in the physical aspects of the sensor layout, I would expect the demosaicing algorithm to be basically identical across all these bodies.

  • by MR.Mic (937158) on Monday November 17, 2008 @11:02PM (#25796725)
    I wonder if this method still holds up after noise removal, or even something as simple as an image size reduction. Anyone more knowledgeable on the subject care to speak up?
    • by morgan_greywolf (835522) on Monday November 17, 2008 @11:04PM (#25796729) Homepage Journal

      I doubt it. I do a LOT of image processing, and I have to say that after color correction, noise removal, etc., I very much doubt that this technique would hold up.

    • by jools33 (252092) on Tuesday November 18, 2008 @03:36AM (#25798691)

      There are photodesk editors with experience who claim to be able to identify the camera model, the lens used and the post processing software used to produce the jpeg / tif file. This is possible due to various characteristics that are introduced at each stage in the digital photographic process. Giveaways for the camera body used are the base resolution, any colour casts in the image, iso performance, dynamic range. For instance many Canon DSLRs are criticised for producing muddy greens in their images - especially at higher ISOs as the dynamic range is pushed to extremes. Then you can usually work out the lens - by the obvious field of view first, then the flaws in the shot - various lenses from various manufacturers have different flaws. For instance the 70-200 f/2.8 from Nikon has characteristic vignetting that can often be noticed even after post processing, then other cheaper lenses give various defects to the image such as chromatic aberation. The flaws in the image give away the body and lens. Also the sensor used gives certain image characteristics that are fairly easy to spot even to the keen amateur photogs eye - for instance telling the difference between a full frame sensor and a smaller APS sized sensor - the full frame image typically has a much smoother more film like attributes with less digital artifacts. Also the same can be said for post processing. This software usually leaves various characteristics - that remain with the image, and this varies for each different software vendor.

      So this is all possible to a well trained human eye - don't see why it shouldn't be possible in software - but not sure of the real benefits of being able to identify this - as many photogs often leave the exif data - and that tells you everything.

  • Raw images? (Score:5, Insightful)

    by evanbd (210358) on Monday November 17, 2008 @11:03PM (#25796727)

    So, if I shoot in raw mode, and then postprocess in software to get a jpeg, the demosaicing signature should merely identify the software, right?

    Of course, I wouldn't be surprised to learn that the distortion uniquely identifies the lens used...

    • And the jpeg encoder will be identifiable as well. (Can't think of the name of the software right now...)
      • Re: (Score:3, Interesting)

        by Guspaz (556486)

        Problem is, you don't need to buy a JPEG codec, so there isn't necessarily anything to trace back to you.

        I mean, what if the JPEG codec is determined to be the one included with MS Paint? How does it help to know that the person you're looking for used a copy of Windows XP or Vista?

        • I don't really see that as an issue. This seems like more of a "additional confirmation" tool that you'd use in the courtroom, rather than as a primary tool that you'd use to discover the identity of a person of interest.

    • by Guspaz (556486)

      One could also potentially design an algorithm that subtly obfuscates the subpixel values in such a way that it defeats the technique while minimizing the apparent visual changes to the image.

      In fact, since JPEG already downsamples the chroma channel, I'd imagine that merely applying JPEG compression would already defeat any attempts to do this...

      Then again, this may all be moot; cameras produce images at increasingly insanely high megapixel counts. what people actually need is often far lower. So as others

      • by Nikker (749551) *
        As long as all the operations are carried out in scale you could likely determine the original 'finger print' since they would likely correspond. This could differ depending on the amount of alteration as well as distribution of the finger print across the pixels. Reducing the image to gray scale then using a separate function to interpret the color from there may be enough in some cases but YMMV.
    • Re:Raw images? (Score:5, Interesting)

      by Facegarden (967477) on Tuesday November 18, 2008 @12:01AM (#25797235)

      ...Of course, I wouldn't be surprised to learn that the distortion uniquely identifies the lens used...

      Nah, not likely. Unless you knew exactly what the scene was supposed to look like, from that exact angle and everything (and even then it would likely be impossible), you just can't know what is a distortion from the lens and what is part of the scene. Unless, like, the scene happened to be a highly accurate checkerboard pattern. Then you can look and see what lines aren't quite straight and get some distortion information, but that would be tough.

      I know software can correct for lens distortion if it has a distortion profile for a certain lens (which is probably made by shooting a checkerboard type pattern...), but knowing to move every pixel to the left one is a lot easier than knowing if every pixel was moved to the left one by the lens, if that makes any sense.

      Put another way, it's easy to put soda in your mouth and have yellow stuff come out of your underbits, but very difficult to do the reverse.
      -Taylor

      • Re:Raw images? (Score:5, Interesting)

        by Speare (84249) on Tuesday November 18, 2008 @12:59AM (#25797713) Homepage Journal
        You really don't need anything so clean and nice as a full-scene checkerboard, to calculate a lot of lens details. Two or three moderate-length manmade straight lines that are at different angles should be enough. Like two edges of a table, a tall building, etc. That should be enough to give you the general curvature coefficients, which in turn would be pretty close to giving the right field of view. I don't think you'd be able to tell Sigma from Canon from Nikkor from Leica from Tokina from Zeiss glass.
      • Re: (Score:3, Funny)

        Put another way, it's easy to put soda in your mouth and have yellow stuff come out of your underbits, but very difficult to do the reverse.

        I'm never drinking Mountain Dew again.

        • by Facegarden (967477) on Tuesday November 18, 2008 @04:42AM (#25799019)

          Put another way, it's easy to put soda in your mouth and have yellow stuff come out of your underbits, but very difficult to do the reverse.

          I'm never drinking Mountain Dew again.

          And you're probably better off. I think Mountain Dew is the byproduct of people who never quite realized that you can't make soda from pee... Well, unless you're NASA I suppose...
          -Taylor

    • Re:Raw images? (Score:4, Interesting)

      by AliasMarlowe (1042386) on Tuesday November 18, 2008 @03:57AM (#25798801) Journal

      So, if I shoot in raw mode, and then postprocess in software to get a jpeg, the demosaicing signature should merely identify the software, right?

      Yes, they're just fingering the in-camera raw conversion to jpeg. Using external conversion changes the game.

      There are comparisons of demosaicing algorithms used on the same raw image at several places on the net, such as http://www.rawtherapee.com/RAW_Compare/ [rawtherapee.com]. The software can make a huge difference, especially regarding moire and related artefacts. Most of the raw converters default to a much too aggressive approach for small scale features, in my opinion. As a result they often create chromatic moire in the JPEG, and accentuate the problem further by sharpening (to hide the softness of typical cheap lenses). This is clearly seen in the examples at the linked site.

      Identical detectors on different cameras usually differ in the optical antialias filter used, which can affect their susceptibility to moire on sharpening. This may leave some residual information to allow the camera to be identified even with external conversion of the raw image. It would first be necessary to identify the demosaicing algorithm/software, so identifying the camera just from residual artefacts from the antialias filter would not be easy.

      Of course, I wouldn't be surprised to learn that the distortion uniquely identifies the lens used...

      Raw processing packages such as Bibble Pro also include a database of distortion characteristics for many lenses, including zoom lenses across their zoom range. Optionally, the image processing can compensate for the distortion for any recognized lens. Of course, the removal of distortion may leave a signature, which will perhaps allow both the lens and the software to be identified. This would not be a trivial task, of course, since "identical" lenses differ in their optical characteristics, and probably none exactly matches its nominal profile.

  • So What? (Score:5, Insightful)

    by Lord Apathy (584315) on Monday November 17, 2008 @11:05PM (#25796741)

    So what if they can identify the make and model of camera. I own a D70. There are 300 billion d70 out there. Good luck on tracking a picture to my camera.

    • Re:So What? (Score:5, Funny)

      by canajin56 (660655) on Monday November 17, 2008 @11:18PM (#25796849)
      They don't have to. All they have to do is say they used forensics just like on CSI, and it shows it was taken by the same kind of camera you own. Sure, you can say there are a lot of them out there so it proves nothing. But you know who else says that? The bad guys on CSI, and their smug, latte drinking lawyers. Always demanding warrants and to be released if they aren't being charged with anything! EVIL
      • In other words, let 'em use what they want as long as the source is provided for the defense.
      • You say this like it's bad news for the bad guys. When really all this means is it's easier for them to pin your crimes on the closest scapegoat.

      • Re: (Score:2, Funny)

        by dattaway (3088) *

        And you know that 1x1 pixel is all the evidence we need. You see, that pixel represents a single atom, which has bands of electrons, each with distinct spins, each of those with unique quantum signatures all the way up to other dimensions in other universes, all tied together with string theory back to the original untouched photograph.

        You may sign the confession now or we will get a court order to further examine the evidence...

        • Re: (Score:3, Funny)

          by Anonymous Coward

          And you know that 1x1 pixel is all the evidence we need.

          "Chief! We only got a 1x1 pixel area of the jpeg of the criminal!" "Okay take it downstairs to Abby and McGeek to check it out".

          [Wiggly Lines]

          "Yeah Chiefy it was pretty easy. We zoomed in on the 1x1 pixel image and we got this picture of the criminal which was inside there. And we got the model of camera he used too, an Motorola RAZR Smartphone." "Yeah Chief, there's only been ninety jillion RAZR phones made, so we hashed the 1x1 pixel image and g

      • Re:So What? (Score:5, Interesting)

        by Anonymous Coward on Tuesday November 18, 2008 @12:00AM (#25797229)

        The bad guys on CSI, and their smug, latte drinking lawyers. Always demanding warrants and to be released if they aren't being charged with anything! EVIL

        The only EVIL on CSI shows is the way the motherfucking cops use extortion.

        "You don't want to give up privileged information on this guy? Fine, we'll be back with a warrant. Of course, we may have to dismantle your office for a couple of weeks to do a thorough search. What does a couple of weeks mean to your business? You do understand, don't you, that when we seize (God, how those bastards love the word "seize") your computer, our clumsy techs might return it with some important files no longer readable? So sorry. ... Oh, yes, ma'am, that's the perp we were inquiring about. Thank you for your cooperation."

      • Re: (Score:2, Informative)

        by Anonymous Coward

        The stuff you see on CSI and other similar crime shows is grossly unrealistic. It's actually so unrealistic that judges typically give a bit to jurors when they're in the panel that they should not put cops onto a standard compared against these shows (no one would ever get convicted). One of my judges used to put it something like this: "You need to understand the difference between reality and television. On these shows, the investigators find a footprint with blood, match it up to a boot tread, then f

      • Re: (Score:3, Interesting)

        by Eivind (15695)

        It's still useful in a negative sense.

        Knowing the picture came from a certain model camera isn't very useful as proof that a certain person took it, afterall there are many cameras that are produced by the million.

        But it is -quite- useful for narrowing the field. Someone who doesn't posess such a camera very likely did NOT take the picture, that's useful information.

        It's like, knowing that a criminal was about 30 and male isn't useful as proof that a certain person did it. But it is -very- useful for elimin

    • Re:So What? (Score:5, Insightful)

      by John Hasler (414242) on Monday November 17, 2008 @11:40PM (#25797041) Homepage

      > Good luck on tracking a picture to my camera.

      That's not the purpose. Knowing the photo was taken with a D70 eliminates all the zillions of cameras out there that aren't D70s. It's like knowing that a bank robber is a 6' tall blue-eyed blond male.

    • Re:So What? (Score:5, Interesting)

      by xIcemanx (741672) on Monday November 17, 2008 @11:42PM (#25797061)

      So what if they can identify the make and model of camera. I own a D70. There are 300 billion d70 out there. Good luck on tracking a picture to my camera.

      RTFA:

      While many people own the same camera models, Pollitt believes that this technique can still be used forensically. He says that because digital cameras have a shelf life of only 18 months, this can help to narrow down when and where it was sold. Just because it won't immediately narrow it down to a single suspect with perfect accuracy doesn't mean it won't be helpful in investigations.

      • Re:So What? (Score:5, Insightful)

        by taustin (171655) on Monday November 17, 2008 @11:47PM (#25797113) Homepage Journal

        Forensically, it's as useful as saying "this bullet came out of this model pistol." Not conclusive by itself, but one piece of a larger puzzle.

        99% of criminal investigation is eliminating who didn't do it, and this can be useful for that.

        • by prockcore (543967)

          I'm just trying to imagine a crime where a photo was taken by the perp and then sent to the cops.. and the make of the camera matters more than the delivery system used for the photo itself.

          • Re: (Score:2, Insightful)

            by penguinchris (1020961)

            It's clearly a technique for child porn investigations. If you have a suspect who owns the same kind of camera you determined was used to take the photo in question, which the investigators most certainly didn't get from the photographer them self, you can know whether to search for more evidence or to eliminate them from your suspect list.

            Most people who do this kind of thing are not necessarily going to realize this is possible, so aren't going to think of the obvious solution, which is to borrow someone

            • Re: (Score:2, Insightful)

              by KDR_11k (778916)

              With child porn investigations this probably counts as sufficient evidence to convict someone seeing how quickly people go rabid when the subject comes up.

            • Re: (Score:3, Insightful)

              by stewbacca (1033764)

              It's clearly a technique for child porn investigations.

              Maybe I'm naive, but it took this long into the discussion thread for somebody to explain why this is even a story. I hadn't thought of that (because I'm a decent human) and I guess everyone else *thought* it, but were a bit uncomfortable stating what is otherwise totally obvious to most folks.

      • Re: (Score:3, Interesting)

        by kent_eh (543303)

        While many people own the same camera models, Pollitt believes that this technique can still be used forensically. He says that because digital cameras have a shelf life of only 18 months, this can help to narrow down when and where it was sold.

        1) RE: Originally sold. My 7 year old carries a 4 Mpixel camera that we bought at a yard sale, which that guy bought off E-bay. "They" might be able to tell that the picture of interest was taken by a camera originally sold at a WalMart in upstate New York, not that it was taken by a kid in Winnipeg.

        2) RE: "shelf life". Of the 25+ cameras that my extended family own, none are newer than 18 months. Most are 2-3 years old.

    • Re: (Score:2, Insightful)

      by xIcemanx (741672)

      So what if they can identify the make and model of camera. I own a D70. There are 300 billion d70 out there. Good luck on tracking a picture to my camera.

      RTFA:

      While many people own the same camera models, Pollitt believes that this technique can still be used forensically. He says that because digital cameras have a shelf life of only 18 months, this can help to narrow down when and where it was sold.

      Just because it won't immediately narrow it down to a single suspect with perfect accuracy doesn't mean it won't be helpful in investigations.

    • Re:So What? (Score:5, Informative)

      by fuzzyfuzzyfungus (1223518) on Monday November 17, 2008 @11:55PM (#25797191) Journal
      I hope the "there are 300 billion of them out there" defence works better for you than it did for certain owners of cheap, common watches [wikipedia.org].
    • by Fastolfe (1470)

      I suspect this would be more useful as a way to exclude cameras that wouldn't have likely taken the photograph. If you have 100 suspects, and can mostly exclude 95 of them on this basis, that's useful.

    • Re:So What? (Score:5, Insightful)

      by vux984 (928602) on Tuesday November 18, 2008 @12:06AM (#25797283)

      So what if they can identify the make and model of camera. I own a D70. There are 300 billion d70 out there. Good luck on tracking a picture to my camera.

      Its useful the same way knowing the car that raced away from the scene of the crime used a particular tire, with a particular wheelbase. Or that a bullet was fired from a particular make of gun.

      Neither will positively identify anyone, but if you were already a 'person of interest' in a long list of people peripherally related to a case that detail might put you on a MUCH shorter list if it comes up that you have that model. Plus its useful when they are asking a judge for a warrant. Judges really like specificity with warrants... A "We want to search his home and car for a Canon Powershot X"; he blogged here about buying a Canon Powershot X, he was caught on this surveillance tape leaving the scene carrying an indistinct object, the dimensions and shape of which are consistent with a Powershot X, and we know the photos in question were taken with a Canon Powershot X"... that's got a lot more weight than... "We want to search this guy for a digital camera, because a witness said he owns a camera, and he was caught on tape holding an indistinct smallish object which could be a camera, oh... and the photos we're interested were taken with a camera."

      A reasonable person would view the second as a complete fishing expedition, based on no evidence, practically everyone has a camera and he could have been holding anything on that tape. The first request is specific - the photos of interest were taken with that model, and there is reason to beleive the person HAS that particular model, and that he had it with him on the that tape. Sure it could be a coincidence, but a warrant for that particular camera if he has one to check it out, might not be unreasonable.

      Its also not unlikely that they can pair photos to a particular camera if they have both on hand due to micro-scrathes and other unique lens defects... the same way they can pair laser pritners to printed output.

    • i have a d70 too!

      and i bought mine used, so even if they are able to trace it back to my exact camera, that doesn't prove that I was the one who shot the image.

      how would this technology deal with used goods and re-sellers?

  • Killjoy (Score:4, Interesting)

    by ciaohound (118419) on Monday November 17, 2008 @11:07PM (#25796759)

    Well, that kind of takes the fun out of this kind of story [luminous-landscape.com] in which images from a Canon point-n-shoot are indistinguishable from those taken by a $40,000 Hasselblad.

    • by Azarael (896715)
      That isn't the conclusion that the author came to. If you compare http://www.luminous-landscape.com/images-85/h2.jpg [luminous-landscape.com] and http://www.luminous-landscape.com/images-85/g10-comp.jpg [luminous-landscape.com] there is definitely a different between the yellows and the depth of focus on the expensive camera is far better (compare the red leaves on the upper left).
      • Re:Killjoy (Score:4, Insightful)

        by Colonel Korn (1258968) on Monday November 17, 2008 @11:49PM (#25797129)

        That isn't the conclusion that the author came to. If you compare http://www.luminous-landscape.com/images-85/h2.jpg [luminous-landscape.com] and http://www.luminous-landscape.com/images-85/g10-comp.jpg [luminous-landscape.com] there is definitely a different between the yellows and the depth of focus on the expensive camera is far better (compare the red leaves on the upper left).

        Depth of field isn't a question of better or worse, you know, it's just different. If you want to poke at that story, you might just point out that a the limited image size makes the comparison pointless. These days, cheap digital cameras make incredibly expensive pro cameras more useful for either flexibility or niche markets (like >13" prints). That doesn't mean professional cameras aren't worth it, just that they're not worth it for everything.

        • by Azarael (896715)
          I don't disagree, the point that I was trying to get at was that the OP's conclusion didn't jive with the site. I've never owned an SLR and I'm pretty sure the majority of the photo quality problems I've had are the fault of the person holding the camera.
        • Re:Killjoy (Score:5, Informative)

          by johnlcallaway (165670) on Tuesday November 18, 2008 @12:22AM (#25797405)
          My wife and I have two point and shoot cameras, a Nikon and an Olympus. We also have a Pentax dSLR.

          Looking at the images at 100% scale and you can see a tremendous difference in the amount of noise in the backgrounds. That is mostly caused by the smaller size of the CCDs and the quality of the sensor itself. Plus, the higher end cameras have far better noise reduction software built in.

          Depth of field is EVERYTHING to taking pictures. By using a long lens and a large aperture, bars around zoo cages disappear, the annoying crowd behind the bride also disappears, or that person just standing behind your subject gets just the faintest blur so your eye is drawn to the subject. Or use a small aperture and everything is brought into crisp focus.

          Then there is being able to use higher quality optics. I recently used the Pentax camera to take some campfire scenes using a 50mm(film) lens set at 1.4f. I was able to take clear, handheld images around the campfire. Try that with a point and shoot.

          I'm not knock the PS cameras. I use them when I'm riding my motorcycle to get action shots of those I ride with. That would be impossible with a dSLR or SLR camera, they are just too big and bulky.

          But if someone wants to take high quality snapshots to share, nothing beats a dSLR. Pricey, yes. But well worth it for the serious photographer, be they professional or hobbyist.
          • Re:Killjoy (Score:4, Insightful)

            by swillden (191260) <shawn-ds@willden.org> on Tuesday November 18, 2008 @02:33AM (#25798287) Homepage Journal

            Looking at the images at 100% scale and you can see a tremendous difference in the amount of noise in the backgrounds. That is mostly caused by the smaller size of the CCDs and the quality of the sensor itself. Plus, the higher end cameras have far better noise reduction software built in.

            In addition to noise, the small digitals show lots of other image degradation as compared to a dSLR. They lack sharpness and have issues with distortion, color accuracy and chromatic aberration. The ultimate source of all of those issues is the glass. You simply can't get the same level of quality out of a half-inch lens as out of series of two-inch lenses (assuming similar technology applied to both).

            I just shake my head at the ever-increasing megapixel numbers on compact digital cameras. I know they're great for marketing, but for the camera owners they do nothing but produce bigger files, with no better image quality than if they'd had a smaller pixel count. Once you get beyond the resolution of the glass, there's just no point in adding more pixels.

            I just read the Haselblad/Canon comparison, though, and I have to point out that the Canon G10 is not what most people think of when you say "cheap digital". It's not an SLR, but it's close, with larger, better glass than most P&S cameras and a larger sensor. 15MP is a bit much for those lenses and that sensor size, but it's not that crazy.

      • by S-100 (1295224)
        You missed the point. He said that every sensor is different, so each needs to be adjusted as desired. Claiming one is "better" because of the yellows is a) not what he said and b) irrelevant to the discussion.

        As for the depth of field, again you get it wrong. Depth of field is adjustable - one camera or image isn't better or worse if shot with a particular depth of field. What he said was that the Blad pictures were shot with a narrower depth of field and that his experts were able to discern which we
  • by syousef (465911) on Monday November 17, 2008 @11:13PM (#25796803) Journal

    You can do all sorts of stuff to an image that would shot holes in this technique. Resize (shrink, or grow and reinterpolate), apply a filter (curves, b&w or sepia would be easiest but there are others). Hell put it through an artistic filter. Still at 90% accuracy, in most cases, I wouldn't even bother!

    • I add comments to all by pictures. This makes it more difficult as well. But I'll admit it's annoying to have "Happy Birthday!!!" on each and every photo.

  • Really... (Score:2, Funny)

    by Mozk (844858)

    All the more reason to use film.

  • Meta data? (Score:4, Funny)

    by Ian Lamont (1116549) on Monday November 17, 2008 @11:13PM (#25796813) Homepage
    Is the make and model data already included in jpeg's file header? See here [googlepages.com]
    • Re: (Score:3, Informative)

      by afidel (530433)
      Yes, it's called EXIF and they are talking about a photo with the EXIF stripped.
  • "Forensics teams are already licking their chops."

    I can only see this, in a positive light, as uncovering fraud or deception -possibly even supporting a claim as to the veracity of a witnesses' testimony to photographing a crime- instead of this being used in a nefarious way. Although, once the algorithm is well understood, certain 'non-well-intentioned' organizations or individuals will use this for evil instead of good. But in the meantime, how would this worry the average digital shutterbug?
    • Could perhaps be used for prosecuting people who take photographs in "forbidden" areas, such as evil people who dare to take pictures in the DC Amtrak station, on the Pentagon reservation, and other such areas. I can't quite figure out how this would play into it though.... And of course as far as I know nobody has (yet!) been prosecuted after the fact for such photographs.

    • Sounds a lot like tracing typewriters to me.
      • by carlzum (832868)
        Except with typewriters and gun barrels there are physical nuances that leave unique markings on bullets/letters. This just identifies the model, and even that's degraded as the image goes through various software manipulations, as other posters pointed out. It may help reduce the population of digital camera owners in question, but it doesn't seem like the kind of evidence forensics teams are "licking their chops" over.
  • I have a friend who is so paranoia about leaving personal data on the Internet he doesn't even use his own name as login name on his iMac. Don't let him hear this or I will never get any pictures from him by mail anymore!

    • Re: (Score:3, Funny)

      by nedlohs (1335013)

      You'll have to tell us who he is so we can be sure not to let him hear.

      • by tsa (15680)

        I guess you're right :)

        The funny thing is: he buys a lot of stuff at the Dutch version of eBay. I wonder how he does that.

  • So when is the first software designed to process photos taken with one model of camera so that they appear to have been taken by another going be available on the Net?

  • This just in... (Score:4, Insightful)

    by fireman sam (662213) on Tuesday November 18, 2008 @12:04AM (#25797263) Homepage Journal

    Cops didn't realize that most pictures posted on the interweb thing are usually post processed.

  • This sounds like the equivalent of "registering" typewriters with the government in nations once behind the Iron Curtain. It is no different than obtaining ballistic signatures from firearms at the manufacturer level. Yet one more reason to distrust governments.

  • Luckily for anarchists, alleged terrorists and people who take pictures of cops thugging out on citizens, today's basic digital camera costs nearly as much as dinner for two at the local fast food joint. "Disposability" is your friend.

  • Rethink (Score:3, Insightful)

    by techdojo (1409685) on Tuesday November 18, 2008 @02:59AM (#25798457) Homepage

    At first blush this struck me as similar to the printers that revealed a specific device by a faint set of dots printed on each piece of paper. On further thought, it occurs to me that the difference would be that the dot-tracking was shady where-as this is a triumph of statistical observation. The former being slimy and the latter sheer brilliance.

    _________________________
    http://techdojo.org/ [techdojo.org]

  • shoot raw (Score:3, Insightful)

    by glyph42 (315631) on Tuesday November 18, 2008 @04:16PM (#25807305) Homepage Journal
    Just shoot raw and process the photos in Photoshop. Then their demosaic algorithm detector will just read "Adobe did it".
  • HOLY SHIT!!!! (Score:3, Insightful)

    by fataugie (89032) on Tuesday November 18, 2008 @04:41PM (#25807705) Homepage

    They figured out how to read the EXIM data stream.

    BRILLIANT!

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