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Identifying Manipulated Images 162

Posted by CmdrTaco
from the check-that-out dept.
Jamie found a cool story at MIT Tech Review. (As an aside, it sits behind an interstitial ad AND on 2 pages: normally I reject websites that do that, but it's a slow news day, so I'm letting it through.) Essentially, software is used to analyze light patterns in still photographs. Once you can figure out where the light sources are, it becomes a lot easier to determine if an image has been photoshopped.
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Identifying Manipulated Images

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  • Steganography (Score:4, Insightful)

    by unbug (1188963) on Monday March 17, 2008 @10:19AM (#22772960)
    Does it also apply to steganography? Would sort of suck if it did.
    • by L4t3r4lu5 (1216702) on Monday March 17, 2008 @10:35AM (#22773078)
      *Somewhere in the middle of the NSA / MI6 buildings, a check mark is put next to an IP address.*
    • Steganography is a good way to hide things from your Grandmother. I wouldn't trust it much past that.
      • Re: (Score:3, Informative)

        by blueg3 (192743)
        There's not much wrong with steganography of encrypted data, particularly if the data in the covert channel would have been statistically similar to random data anyway.

        Most image steganography isn't that great, though, and steganography by a well-known means of cleartext data is fairly pointless.
        • by jd (1658)
          This would presumably work best with HDR images, such as JPEG2000, OpenEXR and the like, as very few image capturing devices could be reliable at 48bpp. Actually, the "ideal" might well be to calculate the degree of randomness in the low-order bits of the image and then pick an encryption algorithm whose typical degree of apparent randomness was closest to the degree of randomness in the image. There may be ways of using compression prior to encryption, or data recovery bits + deliberate corruption to furth
  • by Anonymous Coward on Monday March 17, 2008 @10:23AM (#22772988)
    People who manipulate images will use these tools for quality control: When the fabrication passes all tests, it is ready to be released.
    • by Tjp($)pjT (266360)

      Once you can figure out where the light sources are, it becomes a lot easier to determine if an image has been photoshopped.

      So use the new tool, determine the light sources and then add the correct light sources to you well rendered CGI model. Then the tool says it is "OK" and untampered with? Looks like a Photoshop plugin could be developed to check for this, and then maintain consistency. Just what we need. Better photo counterfeits!
  • by jimboindeutchland (1125659) on Monday March 17, 2008 @10:25AM (#22773006) Homepage
    Duh! [xkcd.com]
  • by Anonymous Coward
    TFA says an "expert user" is required. This expert user inputs coefficients that drive the equations that analyze the picture.

    So basically, if you want an image to be doctored, you use one set of values. If you want an image to be genuine, you use another set of values. Maybe somebody else's requirements differ from mine, but this is not the kind of flexibility I want in a tool that is supposed to tell me if an image has been altered or not.

    For an example of a better tool, see this article [slashdot.org] from Slashdot in
    • by general_re (8883) on Monday March 17, 2008 @11:05AM (#22773360) Homepage

      TFA says an "expert user" is required. This expert user inputs coefficients that drive the equations that analyze the picture.

      So basically, if you want an image to be doctored, you use one set of values. If you want an image to be genuine, you use another set of values. Maybe somebody else's requirements differ from mine, but this is not the kind of flexibility I want in a tool that is supposed to tell me if an image has been altered or not.
      Ummm, what? FTA:

      Johnson's tool, which requires an expert user, works by modeling the lighting in the image based on clues garnered from various surfaces within the image. (It works best for images that contain surfaces of a fairly uniform color.) The user indicates the surface he wants to consider, and the program returns a set of coefficients to a complex equation that represents the surrounding lighting environment as a whole. That set of numbers can then be compared with results from other surfaces in the image. If the results fall outside a certain variance, the user can flag the image as possibly manipulated.
      I mean, that's not even close to what you posted - "running the same analysis on different parts of the image and then comparing the results" is not the same as "you pick the results".
      • by fredklein (532096)
        "running the same analysis on different parts of the image and then comparing the results" is not the same as "you pick the results".


        It is if you get to pick the parts of the image.
  • by Anonymous Coward
    I can tell just by looking at the pixels and cause ive seen a lot of 'shops.
  • by wile_e_wonka (934864) on Monday March 17, 2008 @10:25AM (#22773024)
    The printer-friendly version:

    http://www.technologyreview.com/printer_friendly_article.aspx?id=20423 [technologyreview.com]
    • by IBBoard (1128019)
      Clever (yet annoying). I found that link as well, but it doesn't work.

      First time I hit the article (from the link in the summary) it loaded fine. Clicked your link and I got an ad with the "skip this ad" link (although the ad wasn't there because of AdBlock) then it took me to the main article across two pages.

      Looks like those damned evil news people don't want us to avoid their adverts.
      • by trolltalk.com (1108067) on Monday March 17, 2008 @11:07AM (#22773380) Homepage Journal

        The link works fine if, instead of clicking on it, you cut-n-paste it into a new browser tab. Here's what you get, if you can't be arsed to go to the trouble:

        Monday, March 17, 2008
        Identifying Manipulated Images
        New tools that analyze the lighting in images help spot tampering.
        By Erica Naone

        Photo-editing software gets more sophisticated all the time, allowing users to alter pictures in ways both fun and fraudulent. Last month, for example, a photo of Tibetan antelope roaming alongside a high-speed train was revealed to be a fake, according to the Wall Street Journal, after having been published by China's state-run news agency. Researchers are working on a variety of digital forensics tools, including those that analyze the lighting in an image, in hopes of making it easier to catch such manipulations.

        Tools that analyze lighting are particularly useful because "lighting is hard to fake" without leaving a trace, says Micah Kimo Johnson, a researcher in the brain- and cognitive-sciences department at MIT, whose work includes designing tools for digital forensics. As a result, even frauds that look good to the naked eye are likely to contain inconsistencies that can be picked up by software.

        Many fraudulent images are created by combining parts of two or more photographs into a single image. When the parts are combined, the combination can sometimes be spotted by variations in the lighting conditions within the image. An observant person might notice such variations, Johnson says; however, "people are pretty insensitive to lighting." Software tools are useful, he says, because they can help quantify lighting irregularities--they can give solid information during evaluations of images submitted as evidence in court, for example--and because they can analyze more complicated lighting conditions than the human eye can. Johnson notes that in many indoor environments, there are dozens of light sources, including lightbulbs and windows. Each light source contributes to the complexity of the overall lighting in the image.

        Johnson's tool, which requires an expert user, works by modeling the lighting in the image based on clues garnered from various surfaces within the image. (It works best for images that contain surfaces of a fairly uniform color.) The user indicates the surface he wants to consider, and the program returns a set of coefficients to a complex equation that represents the surrounding lighting environment as a whole. That set of numbers can then be compared with results from other surfaces in the image. If the results fall outside a certain variance, the user can flag the image as possibly manipulated.

        Hany Farid, a professor of computer science at Dartmouth College, who collaborated with Johnson in designing the tool and is a leader in the field of digital forensics, says that "for tampering, there's no silver button." Different manipulations will be spotted by different tools, he points out. As a result, Farid says, there's a need for a variety of tools that can help experts detect manipulated images and can give a solid rationale for why those images have been flagged.

        Neal Krawetz, who owns a computer consulting firm called Hacker Factor, presented his own image-analysis tools last month at the Black Hat 2008 conference in Washington, DC. Among his tools was one that looks for the light direction in an image. The tool focuses on an individual pixel and finds the lightest of the surrounding pixels. It assumes that light is coming from that direction, and it processes the image according to that assumption, color-coding it based on light sources. While the results are noisy, Krawetz says, they can be used to spot disparities in lighting. He says that his tool, which has not been peer-reviewed, is meant as an aid for average people who want to consider whether an image has been manipulated--for example, people curious about content that they find online.

        Cynthia Baron, associate director of digital media programs at N

    • Sorry people--it doesn't work.

      Darn advertisers!
  • with all those UFO hoax photos then... /I want to disbelieve
    • Re: (Score:3, Informative)

      by zotz (3951)
      Funny thing, you don't always have to shop things to get odd results:

      My vids on youtube:

      http://www.youtube.com/user/zotzbro [youtube.com]

      If you check the comments on the "UFO vs Paper plane test" you will see people talking of a real one.

      Perhaps on some of the paper plane instruction vids too. If you watch those, as the camera pans in one of them, after the construction and before the flight test, you can see what the "UFO" really is.

      all the best,

      drew
      http://zotzbro.blogspot.com/ [blogspot.com]
    • Re:That should help (Score:5, Informative)

      by sm62704 (957197) on Monday March 17, 2008 @11:26AM (#22773552) Journal
      It's not needed and won't help. Most of the UFO photos are pre-Photoshop and were done with different methods:
      • Have a small model of the UFO and fling it into the air high enough that there's no context. Although those CAN be detected, they can't by this software.
      • The objects are secret military aircraft, not alien craft. The hoax of alien craft is started by the government (pick one) to mask the true meaning of the object photoed. This software won't help with that, either
      • It's something else flying around up there. Is it a bird? Is it a plane? Is it a weather balloon? Is it ball lightning? Who knows? If it's a flying thing and you don't know what it is, then it's an Unidentified Flying Object. This tool won't help here, either.
      This tool can't do anything someone trained in art can't do. The first thing you learn in art school is how to see. You can't draw if you can't see, and that's usually the biggest reason most people can't draw.

      As one of my instructors used to say, "I don't know what I like but I know what art is."

      -mcgrew
  • by jimwelch (309748) <jimwelchok.gmail@com> on Monday March 17, 2008 @10:31AM (#22773054) Homepage Journal
    Someone wore a photo mask and tripped a speed camera to give their partner proof that they were across town (LA) at the time of the murder. He noticed the shadow under the nose was wrong by comparing previous and following pictures from the same camera.
    I am not sure which episode it was. Peter Falk as Det. Lt. Colombo
  • Uh Oh (Score:5, Funny)

    by Missing_dc (1074809) on Monday March 17, 2008 @10:31AM (#22773058)
    This bodes ill for all those geeks out there with "out-of-state" girlfriends!!
  • Goes both ways (Score:5, Insightful)

    by Nerdposeur (910128) on Monday March 17, 2008 @10:32AM (#22773066) Journal
    ...and then the photoshoppers will write evolutionary algorithms to modify their photographs until they pass evaluation by this tool.
  • weak (Score:4, Interesting)

    by gnudutch (235983) on Monday March 17, 2008 @10:33AM (#22773070)

    this method is way better

    Forensic Analysis Reveals Al-Qaeda's Image Doctoring [slashdot.org]

    • way better? (Score:2, Interesting)

      by CrazeeCracker (641868)
      The interesting thing about that is... The code used in the article the OP linked to features the following lines:

      Revision history: This code has been stripped out of imgana by Hacker Factor Solutions. (Imgana does much more than quality analysis, but that's all that is being released right now.)

      Said program by Hacker Factor is also mentioned in TFA as a more basic approach to checking whether or not an image has been manipulated. I'll leave you to judge what this means.

      As an unrelated sidenote, Hacker Factor features a very interesting javascript that guesses the gender [hackerfactor.com] of the author of a block of text (>300 words). Thus far, I've found it to be eerily accurate.

      • I found it eerily inaccurate.

        I threw a bunch of random samplings of English text from Project Gutenberg at it. It claims almost everyone is male.

        -- Terry
      • I haven't tested it extensively, but every chunk of text I threw at the program, it asserted was authored by a male. And yet, more than half the samples were from papers/blogs/fiction authored by female friends. I think that the program assumes that if you are even vaguely literate, you must be male.
    • If you read the linked article, you'll notice that Neal has some responses to questions posted. He used both methods in his Blackhat presentation.
  • Limited utillity (Score:3, Informative)

    by johnjaydk (584895) on Monday March 17, 2008 @10:38AM (#22773116)
    In a studio or other arranged settings it's pretty standard to use multiple lighting sources. So this tool will mainly be usefull for outdoor settings. If it's up-close and personal then it's also very common to use lights or other tools outside. Sooo this tool should be used with moderation.
    • Re: (Score:3, Insightful)

      by aadvancedGIR (959466)
      Moreover, it is well known that photoshop is a standard and commonly used tool for professional studio photography anyway. I think the tool purpose is limited to check that a "genuine" photography used to prove a crime or the existence of UFO/Bigfoot is not a blatant fake.
  • by crowemojo (841007) on Monday March 17, 2008 @10:41AM (#22773142)
    One would think that it would be simple enough, after finishing whatever touch-ups that you want to perform, that you use this technique to calculate where the light sources should be, and then correct the minute details that would give it away as an altered image. Sounds like the kind of thing that would be a simple photoshop plugin actually, once you are all done you just run the "make undetectable from light source detection analysis" tool and call it a day.
    • Re: (Score:3, Interesting)

      by CambodiaSam (1153015)
      Light sources have always been a pain for me when photoshopping. I'm not surprised that it's the key to this software, as it tends to be the most difficult aspect of manipulating an image (I'm a slightly more than casual user, but not a graphic designer). Light completely changes the color structure and I end up spending an inordinate amount of time trying to redo hues and fix shadows that don't line up.

      If there's a plugin for helping me with that part of the struggle, I hereby scream to my fellow slashdott
  • by Dan East (318230) on Monday March 17, 2008 @10:44AM (#22773176) Homepage Journal
    Does anyone else have a habit at looking at pictures and trying to see how they've been manipulated? These types of pictures are rampant in advertising. Pick up any magazine and start looking, and the poorly edited pictures will jump out quickly. The more professionally edited pictures have much more subtle problems, and can take a bit of poring over to find. Many product images (on packaging and in catalogs) are the same way, and are usually the worst edited of the bunch. Some things I look for:
    • An object rubber-stamped in multiple places. Each copy is identical, which gives it away. They are often scaled, rotated or mirrored to make them look more unique.
    • Lighting and shadows, which is what the algorithm in this story deals with specifically.
    • Focus. Often multiple objects will be in focus at varying distances impossible with a single shot.
    • The same image of a person is used in multiple shots. This is most prevalent in product images in catalogs.
    • Poor masking, where edges of objects are over or under processed, either clipping part of the object (hair can be particularly tough to do), or showing some color edges from the original background.

    Anyway, that's just the geek in me I guess, because I really do enjoy finding flaws in images. What I hate is an image that has a sort of surreal perfection to it that I know must be composited, but I can't find any smoking gun.
    • by jo42 (227475)
      "If it looks too good to be true, it is."
    • Re: (Score:3, Funny)

      by Dmala (752610)
      Playboy is probably the worst offender at this. Most of the women these days are so heavily airbrushed/Photoshopped that they look more like paintings or cartoons than actual photos.

      Er... I mean... I just read the articles, but that's what a friend told me about the pictures.
    • Essentially all catalog images are manipulated. Some are even computer renders rather than real photos. My housemate used to work for a company that imported a lot of the stuff sold in Argos (UK crappy catalog chain). They used to sometimes submit the product photos before the actual items existed, while they were still being manufactured in China.
      • by Dogtanian (588974)

        Some are even computer renders rather than real photos.
        Yeah, but doesn't the "cheap plasticky" appearance of the rendered product shots give it away? Oh, hang on....

        a lot of the stuff sold in Argos
        ....scrap that question. In Argos' case, I doubt anyone would be able to tell the difference! ;-)
    • by Atario (673917)

      Focus. Often multiple objects will be in focus at varying distances impossible with a single shot.
      This is perfectly possible, given a small enough aperture setting in your camera and correspondingly high light level in your studio.
    • >"Focus. Often multiple objects will be in focus at varying distances impossible with a single shot."

      Not at small apertures (high F-stops) [wikipedia.org].

    • Ah, yeah...no kidding. I work in China and view a lot of factory catalogs, they have lots of cheap manipulations like that. The creepiest one was a catalog for a garment manufacturer...on every page, on every outfit, was the same grinning blonde guy. After a few pages, it started to get funny. After a few more pages, it got geniunely eerie. Every page, the same rictus grin, flipped left and right. I had to put the catalog down after a while, it was getting to me. Sort of like Aphex Twin's "Come to Da
  • Good (Score:1, Offtopic)

    by Fri13 (963421)
    Now when we have a tool what shows when image is manipulated by using Photoshop, we can start using GIMP or any other _image manipulation_ software because those tools cannot trace them because they dont "photoshop" images, they manipulate them.

    Yah, bad sarcasm, im just tired that "photoshop this" "photoshop that" like there would not be any other image manipulation software. I bet that over 50% Photoshop owners just has a warez version of it and 80% of photoshop users could do their things with any other s
    • Re:Good (Score:4, Funny)

      by Marvin01 (909379) on Monday March 17, 2008 @11:10AM (#22773414)
      It just sounds wrong to say that an image has been "GIMPed".

      Actually, now that I think about it, I kinda like it...
    • by qoncept (599709)
      they dont "photoshop" images, they manipulate them.

      I hope you don't have a runny nose or a paper cut, because you'd probably get upset if someone offered you a Kleenex or Bandaid. Unless those don't fit your agenda. All the pros are using MS Paint anyway.
    • Re: (Score:3, Funny)

      by glwtta (532858)
      im just tired that "photoshop this" "photoshop that" like there would not be any other image manipulation software

      Do you also hang around the Epson at work explaining to people how they aren't really "xeroxing" anything?
    • Re:Good (Score:4, Insightful)

      by dotancohen (1015143) on Monday March 17, 2008 @11:33AM (#22773636) Homepage
      That's why I say "to gimp a photo" rather than say "to photoshop a photo". It spreads awareness, breaks the Adobe monopoly, and sounds more natural. Even Adobe discourages the use of "photoshop" as a verb.
      • Re:Good (Score:5, Insightful)

        by m.ducharme (1082683) on Monday March 17, 2008 @11:55AM (#22773874)

        Even Adobe discourages the use of "photoshop" as a verb.
        You know why, right? If they let "photoshop" be corrupted in the language as a verb, they would eventually lose the trademark rights to the name. Eventually, companies would be able to get away with naming their software "MS Photoshopping Program" or "Gimp Photoshop Utility" or whatever, and Adobe wouldn't be able to do anything about it.

        Are you sure now, that you want to discourage people from using "photoshop" as a verb?
        • by Herkum01 (592704)

          You photoshopped my comment!

        • by Reziac (43301) *
          Actually, they have to be SEEN to discourage its use, lest they lose the trademark.

          But you can bet Adobe is secretly pleased that almost every time someone mentions a manipulated image, their brand-awareness gets a small but definite boost. I know people who think that ONLY Photoshop can be used for such manipulation, in part thanks to this verbification.

          • True. Of course, it's a somewhat dangerous game to play, actually losing the trademark would be a big fail for Adobe. The resulting flood of ersatz photoshop products would wash the marginal gains in brand awareness away.

            Also, Adobe's brand would be eroded, not marginally boosted, if there were actually a feature-for-feature competitor for it's product. Note how kleenex is such a generic term, because there is no real difference between a Kleenex, and any other brand of paper snot-wipes.
            • by Reziac (43301) *
              Yeah, it's a risky game all right. But Hormel seems to do okay with SPAM vs spam :)

              Unfortunately trying to maintain a lost brand trademark by being the best in the field doesn't work, since most people buy cheapest regardless of quality. :(

        • by The Queen (56621)
          So is Google discouraging this practice, as well? Seems a bit late.
          • Yes, they are (or rather, they have). Google sent out a round of letters in 2003 and 2006 to various websites where "google" was being used as a verb. Google "google trademark protection" for examples.
        • This already happened in my country (Uruguay) for other stuff: we call chewing gum "chicles" after the Addam's Chiclets brand , and running/tennis shoes "championes" after the Champion brand (that term's unique to Uruguay I think, in Argentina they use the term "zapatillas").
      • by tepples (727027)

        That's why I say "to gimp a photo" rather than say "to photoshop a photo". It spreads awareness
        At least one YTMND user agrees: "GIMP up an image, make it look bad" [ytmnd.com].
    • "im just tired that "photoshop this" "photoshop that""

      Just "Google" it. It is a legitimate verb now.

      "I bet that over 50% Photoshop owners just has a warez version of it and 80% of photoshop users could do their things with any other software"

      And I bet there is a 100% chance you pulled those numbers from right out of yer ass. Thinking something doesn't automagically make it a fact. And haven't you ever seen the GIMP vs. Photoshop discussions like a million times on Slashdot before? If not let me cond
      • Indeed. The number is probably closer to 90% of photoshop "owners" have warez copies. At least based on my own, rather poor sampling: I have met two, maybe three people who have or had at one point warez copies of photoshop, and only zero people who are actually professional graphic artists. Therefore illicit casual users vastly outnumber professionals.
        • by blincoln (592401)
          I'm sure it depends on what community your data is sampled from.

          In the business world, most copies are probably legitimate. Hobbyists and amateurs probably have bootleg copies (aside from the serious hobbyists who feel compelled to buy one), because Adobe prices it as a business tool. Plain old Photoshop CS3 is US$650 for the full version. "Extended" is US$999. If you want the whole Creative Suite, it ranges from US$1199 to US$2499. I do photography as a hobby, and my camera (a secondhand D70) cost less tha
  • Apollo (Score:4, Funny)

    by sir_eccles (1235902) on Monday March 17, 2008 @10:57AM (#22773288)
    I love how the first comment is asking if the apollo landing photos were photoshopped.
  • Elvis is always spotted in 7-11.

    Easily masked light sources (hint: they're everywhere!).
  • Or, with most dumb$*@&s who like to play off photoshopped images as real,

    $ strings pic.jpg | grep -i photoshop
    • by blueg3 (192743)
      It's a lot easier to edit those fields than to properly redo all the lighting so that a lighting-analysis program can't detect it.
  • Anyione else notice the tyipo?
  • speaking of which (Score:5, Interesting)

    by circletimessquare (444983) <circletimessquare&gmail,com> on Monday March 17, 2008 @12:14PM (#22774072) Homepage Journal
    did anyone else catch the blog in the new york times about the fenton photographs [wikipedia.org]?

    apparently this guy took some photos of some cannonballs in the crimean war that became famous as a poetic commentary on war. this documentary filmmaker, errol morris [wikipedia.org], has gone completely unhinged obsessive compulsive over whether or not the photos are fake and/ or manipulated. it's utterly fascinating, and a little weird, to see so much time and effort devoted to these photos. specifically, cannons and shadows. utterly esoteric and thorough. he also expands into the larger topic of the history of manipulated politically sensitive photos. makes for a good read, especially if you are interested in pre-photoshop image manipulation

    check it out, talk about thorough [nytimes.com]
  • Hany Farid, a professor of computer science at Dartmouth College...says that "for tampering, there's no silver button."
    Silver button? What the heck is a silver button?

    I'm assuming he was trying to say silver bullet. Do we blame the professor, or the journalist?
  • Taco, I will try not to make the obvious "anal" jokes, but FFS, is clicking spellcheck really so hard?
  • Light source analysis was one of several methods used at a talk at Blackhat DC this year. The much more visually impressive tool, for me, was the ability to show quite explicitly what has been modified in a lossy-compressed (like jpeg) image:

    http://www.blackhat.com/presentations/bh-dc-08/Krawetz/Presentation/bh-dc-08-krawetz.pdf [blackhat.com]

    Compresion analysis tool:
    http://www.blackhat.com/presentations/bh-dc-08/Krawetz/Extra/jpegquality.c [blackhat.com]
  • "photoshopped"? (Score:3, Insightful)

    by Lxy (80823) on Monday March 17, 2008 @02:16PM (#22775512) Journal
    When did "photoshop" become a verb?

    This post has been gimped by the gimper
  • by Reziac (43301) * on Monday March 17, 2008 @02:27PM (#22775658) Homepage Journal
    ...and for diagnosing damaged JPGs (I used it extensively when reconstructing mangled JPGs from someone's disk crash):

    JPEGsnoop, by Calvin Hass
    In very active development; suggestions and bug reports welcome. Free download from http://www.impulseadventure.com/photo/jpeg-snoop.html [impulseadventure.com]

  • ... normally I reject websites that do that...

    Sorry, Taco, I'm not buying it. This statement implies that Slashdot "editors" actually read the links in the submitted articles, or at least click on them. We all know from past experience that that's just not true.
  • by certsoft (442059)
    That's how Lieutenant Gaeta cleared Dr. Baltar over the faked photograph.
  • Of course, we've heard stories about staffers at papers and magazines faking or 'enhancing' photos. If it happens with people ON STAFF, then why do news outlets take hand-out art from companies, foreign governments and other non-trusted sources?

    For years, I have made my living as a freelance news photographer, and am a member in good standing with several professional organizations. Sure, I could still lie, doctor photos or submit work that isn't my own; but I have added incentive not to: I depend on b

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