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Science

Image Doctoring Is Tough To Spot, Even When We're Looking For It 61

An anonymous reader writes with a link to The Stack's look at study that examines the human capacity to detect (or to overlook) manipulation in images. About 400 volunteers looked at images which had been digitally altered by erasing elements, by replicating parts the image, or by pasting in elements from other images. Less than 58 percent of the alterations were detected, even though the volunteers knew that's what they were to look for. The article says "While its conclusion – that we are not very good at identifying doctored photos – is predictable, it's the type of 'fakes' that deceive us which are most interesting." Spoiler: Erasure is much harder to spot than image splicing.
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Image Doctoring Is Tough To Spot, Even When We're Looking For It

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  • You just have to see if any of the pixels are wrong. Oh, and flags on the moon should hang down.

    • You do know, don't you, that there's a rod inside the top of that flag to hold it out like that?
    • You just have to see if any of the pixels are wrong.

      True, but the vast majority of the public would not know what to look for or even think of zooming in to the pixel level, looking at independent colors for uniformity, etc.

      Oh, and flags on the moon should hang down.

      I assume that you are being sarcastic (grin)... but, just in case, the flag had a metal rod running across the top to keep the material from drooping, otherwise it would have...

      • by Anonymous Coward

        Hell I spent most of my life studying computer graphics. On a good monitor I can spot those pixels that are coming out of my algorithm very subtly wrong, down to an accuracy of 5ish on your typical 0-255 scale for color components. Still some fakes fool me just fine. All it really takes is a little care with lighting and luminance balance. At that point barring the obvious artifacts it's very hard to spot a fake when you do know what to look for.

  • by He Who Has No Name ( 768306 ) on Sunday September 20, 2015 @02:44AM (#50559821)

    A couple decades from now, we're going to have generations that have never known an era when it was technically or logistically difficult to convincingly revise AND distribute photos and videos.

    Beyond simply telling that stuff has been tampered with or invented wholesale, I'm really worried this is going to lead to a loss of credibility and gravitas of photos and videos of historic events.

    It's going to get ugly when generations start denying and rewriting history because they lost trust and belief in the credibility of the medium used to preserve its records.

    • by mentil ( 1748130 ) on Sunday September 20, 2015 @03:58AM (#50560001)

      This has happened before. People who gain critical thinking look back upon what they were learned about history in school or books, and realize that much of it is heavily colored by biases popular in that place and time. '1984' made the concept of rewriting history well-known, although propagandized 'interpretations' of historical events surely predated it. That someone went to the trouble to write a long description of an event indicates a motivation to do so, but that motivation may not be a desire to record or disseminate the truth; therefore, being written down is not proof of its truthfulness.
      For example, it used to be a common occurrence for trusted/respected writers to have new writings attributed to them in order for their 'legitimacy' to be improved. Thus the large amount of apocryphal writings that exist. The Wright bros. weren't believed by journalists at the time that they'd achieved controlled flight; later, they withheld their flyer from the Smithsonian unless they agreed to acknowledge them as the inventors of controlled flight and ignore all the others who worked on airplanes at the time; so the media can get it wrong coming and going.
      And then there's the whole 'mainstream media'/Faux News problem, presenting 1/3 of a story and encouraging people to jump to conclusions.
      In the past, storytelling was the main method of history preservation. Look at how many myths and urban legends that led to, as well as gross embellishments a la Journey to the West. When you were a kid, chances are you believed a myth or 50; how did you feel when you grew up and realized they were nonsense?
      In the end it's going to come down to chains of evidence leading to a trustworthy content creator: a well-known photographer, speaker, or a journalist who goes right to the source. If it originated from an anonymous internet account, then it's less trustworthy.

    • by Anonymous Coward

      It's going to get ugly when generations start denying and rewriting history because they lost trust and belief in the credibility of the medium used to preserve its records.

      Yes, but not as ugly as it was before people lost their trust.
      Looking back trough my old history books from school and comparing it to what I've read from more reliable sources I can see that a lot of the things regarding the timespan between 1600-1800 is utter bullshit. Or more precisely, people who were in power in that time found ways to glorify themselves in ways that were brought into the history books because the people in power controlled what authoritative sources were.
      When it comes to documenting t

    • Beyond simply telling that stuff has been tampered with or invented wholesale, I'm really worried this is going to lead to a loss of credibility and gravitas of photos and videos of historic events.

      It's going to get ugly when generations start denying and rewriting history because they lost trust and belief in the credibility of the medium used to preserve its records.

      Perhaps we should re-embrace film. Sure, you can do almost the same thing with film, the Three Letter Agencies, both United States and the Communists did it on a regular basis, but it's a bit harder than in PhotoShop.

      • by Chaset ( 552418 )
        One of the ideas I've had for a long time is to make digital cameras that cryptographically sign every photo. Maybe such things already exist. I'm not expert enough on those matters to tell whether there are pitfalls in this idea. The key would have to be buried in the silicon somehow such that attempts to get at it would destroy it.
  • by Anonymous Coward

    .... did not evolve to deal with camera's that can take super accurate photos and software with clever mathematics that can manipulate them.

    A good example is hollywood special fx and how it evolved from stop motion and claymation/modelling to computer rendering. When you look at how we tried to fake images in the past we were pretty bad at it. We've gotten so good that the time and tools you'd need are pretty much expert status with special tools.

  • False premise (Score:5, Interesting)

    by DNS-and-BIND ( 461968 ) on Sunday September 20, 2015 @05:35AM (#50560163) Homepage
    I know these sorts of articles are wildly popular these days, showing HOW DUMB ALL OF YOU OTHER PEOPLE ARE. I understand, it's very reassuring to see yourself placed in the top position where you can shit on everyone else. Thousands of years of tyrannical human elites agree with you. But you don't need everyone to see it. It just takes a single person to spot that something is wrong, point it out, and the viral internet takes over from there. That's how Tom Brokaw's fraud was exposed, someone said, "Hmm, that looks just like MS-Word" and then made the animated .gif that changed the world [wikimedia.org]. Thinking that everyone needs to be a Photoshop expert is just naive and misanthropic. Reuters was also caught red-handed altering photos to conform to their narrative [ynetnews.com]. It just takes one person to utter the sacred phrase "Hmm, that's funny". [americanscientist.org]
  • by Anonymous Coward

    Spoiler: Erasure is much harder to spot than image splicing.

    I dunno... the Erasure in this image [virginmedia.com] is incredibly obvious if you ask me.

  • by Anonymous Coward on Sunday September 20, 2015 @07:24AM (#50560357)

    One easy way I found to make some tidy shops is resize the image to quadruple its resolution and edit it there.
    Then, when you are done, resize it back.
    It smooths things together pretty nicely on a sub-pixel level that is usually undetectable even to machine-scanning techniques.
    Of course, if you have the original image, it will be trivial to spot the edit regardless, but it will be harder to figure out which one is the original image.

    Another I have been experimenting with is adding in grainy-looking texture from awful quality CCDs at that quad-res layer.
    It is far easier to do this at the quadruple resolution because the botched noisy pixels will be enlarged quite considerably.
    Now instead of nearly breaking your arm trying to be overly precise, you can easily just draw a circle and apply whatever color or filter to it. (in another layer, of course!)

    Sooner or later, with smarter editing software, it is going to be damn near impossible to tell an image is edited without the original.
    People in any position of power will be able to, quite literally, rewrite history. (not that this has changed anything, this has been true for thousands of years)

    • Re: (Score:3, Interesting)

      by Anonymous Coward

      Yeah, this is pretty good-sounding stuff.

      To some extent I've used that "scaling up" trick myself, though that's usually if I want to tidy up a soft-edged logo or whatever. Simply increasing the contrast at low resolution gives jaggies. Scaling up massively, *then* performing various filters before increasing the contrast to give a very sharp edge looks much better when it's scaled back down.

      I often add noise to edited portions of an image that have no grain or noise, so that they more closely match the appe

  • by sleepypsycho ( 1335401 ) on Sunday September 20, 2015 @07:42AM (#50560383)

    Look at the high variance images at the top of page 9 of the original article. I finding unsurprising at all the people can't tell if a sand dune was smoother or if erasures occurred on image of pine tree branches against pale blue sky.

    One documentary on the development of new currency said portrait sizes were increased because of our ability to notices small variation in faces. I don't have the reference for this, but my personal observations match the claim.

    My wife and I are both artists with masters of fine art in painting. For years, bad effects in movies will jump out at us. We will sometime refer to the "cgi cast of thousand" in egregiously offending movies. For some years now my ability to identify cgi inanimate objects has almost disappeared. In modern movies I almost never have a cgi object jump out at me. I notice that the cgi animation of people is similar improving, although glaring problems still appear. I am sure it has both to do with complexity of the physics problems and my own visual capability and nature focus of attention. I except it is few short years until I almost never notice any cgi modifications.

    • by Anonymous Coward

      Faking realistic objects in a computer has come a long way in the last couple of decades. It really is mostly a problem of computing how light interacts with the object and the models for that have improved tremendously. Human hair and skin are among the harder things to get right because light takes surprisingly complicated paths through them. But both the increase in computing power and more sophisticated algorithms that get used in the industry are closing that gap. Look up the term "physically based ren

  • by ThaumaTechnician ( 2701261 ) on Sunday September 20, 2015 @08:04AM (#50560425)

    From my experience, professional photographers, photo lab technicians, and their ilk, who spend lots of time looking photos and their technical aspects (sharpness, lighting, colour, pixelation, etc, etc, etc), would easily spot the, to me, obviously edited photos. Case in point: the top photo in the The Stack article - clinton-fake-photo-832x333.jpg - is so obviously faked that I'm surprised that anyone would be fooled by it.

    First dead giveaway: Clinton's head is illuminated from the right-read as is Mandela's(?) head. De Angelis's head? From the top-front. (I can't believe that De Angelis's victims didn't spot that fakery.)
    Second less-dead giveaway: the pixelation isn't quite the same. The imposter's pixels are larger, not by much, than Clinton's - at least in the sample from the article.

  • by Anonymous Coward
    All you have to do is look at who is the publisher. If the parent company is owned by Rupert Murdock or say American Media and it is a picture of a celeb then chances are the image has been run over by photo shop.
  • by Sowelu ( 713889 ) on Sunday September 20, 2015 @08:13AM (#50560443)

    Didn't see anything in the article or PDF that would point me at them. If anyone knows where they might be lurking, I'd love to see 'em.

  • I'm surprised no one else has posted this, but the address of the actual test is
    http://newton.inf.ufrgs.br/ [ufrgs.br]
    You have to register, and fill in a small survey consisting of your experience with image manipulation, but its still up as of this post.
  • by chefmonkey ( 140671 ) on Sunday September 20, 2015 @12:59PM (#50561583)

    Erasure is much harder to spot than image splicing.

    My wife once spotted Andy Bell in the crowd at a B.E.F. concert outside of London. Does that count?

  • by Anonymous Coward

    Convincing photo editing is a reality- so if we want to be able to trust photographic evidence we need a foolproof way to detect image manipulation. Cameras could add an encrypted checksum to the meta data of each digital photograph. Any change to the image should change the checksum, and since since the editing program wouldn't have the camera's encryption key it couldn't re-generate the encrypted checksum. The real trick is what encryption will be secure for a long time? Of course there is no w

  • All I can think of is all those "experts" claiming Obama's birth certificate was a forgery because they could tell when something has been photo-shopped.

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