8 ms·

Signs that can reveal a fake photo (2017)

83 points by hiddencache 5y ago

hwers 5y ago
I wonder why the article has the title '20170629-the-hidden-signs-that-can...' in the url. That date would suggest it's from the 29th of june 2017 (while the date below the headlines says 2020), way before the current breakthroughs of deep fakes.
- commoner 5y ago
  Nice catch. The article was republished. Here's an archive from 2019 of the original 2017 version: https://web.archive.org/web/20191030232152/https://www.bbc.com/future/article/20170629-the-hidden-signs-that-can-reveal-if-a-photo-is-fake https://web.archive.org/web/20191030232152/https://www.bbc.c...
  - hwers 5y ago
    I'll be honest and admit that in taking a second look I noticed that they totally admit to this being a republished article from earlier: "[...] BBC Future has brought you in-depth and rigorous stories to help you navigate the current pandemic, but we know that’s not all you want to read. So now we’re dedicating a series to help you escape. We’ll be revisiting our most popular features from the last three years in our Lockdown Longreads.[...]"
    - commoner 5y ago
      I didn't see that, either. My eyes glossed right over the italics.
    - dang 5y ago
      Still kind of dodgy not to include the original date, and to display today's date in exactly the same way that a publication date is usually displayed.
- dang 5y ago
  We've added the year to the title now. Thanks!
hk-im-ad 5y ago
With GANs, any fake image detection technique you could derive based on visual data could probably be learned by the discriminator given the right architecture choice.
- Cthulhu_ 5y ago
  It's an interesting rat race to see; you could make a fake image using AI, then a fake image detector software, then connect the two until the AI generates images no longer recognizable as fake.
  - DonHopkins 5y ago
    Since so many people don't care about the truth, and LARP that they believe fake news and fake images just own the libs, maybe there's some money to be made by selling them fake fake-image-detector software like Hotdog Or Not: one app that always claims a photo is real, and another app that always claims a photo is fake. Or a single app with in-app-purchases that lets them pay to choose whatever they want to believe! https://www.theverge.com/2017/6/26/15876006/hot-dog-app-android-silicon-valley https://www.theverge.com/2017/6/26/15876006/hot-dog-app-andr...
  - hwers 5y ago
    Just a comment: This usually isn't how GAN progress is made. I haven't really seen any GAN that incorporates advances in 'fake detection' directly into its discriminator. Usually it's just GANs getting more data and using smarter math and 'fake predictors' following the development by some 6-12 months.
  - hk-im-ad 5y ago
    This is how a GAN works. There is a generator and a discriminator. The generator tries to fool the discriminator, and the discriminator tries to detect images generated by the generator. As one gets better, so does the other, until progress converges.
ChrisMarshallNY 5y ago
I remember this, when it was first published. Good article. One thing about fakes, is that they don't need to be super-high-quality, in many cases. They just need to be enough to reinforce a narrative to a receptive audience. An example is that Kerry/Fonda fake. Just looking at it as a thumbnail on my phone, it was easy to see that it was a composite. Also, I have seen both photos, in their original contexts. They are actually fairly well-known images, in their own rights. That didn't stop a whole lot of folks from thinking it was real. They were already primed. The comment below, about using an AI "iterative tuner" is probably spot-on. It's only a matter of time, before fake photos, videos, and audio, are par for the course.
- wussboy 5y ago
  I used to think that the internet would be the greatest tool for human peace ever invented. But I was wrong. I didn’t know that humans don’t use reason to determine their position. The use it to justify their position and Google provides the greatest tool ever built for allowing people to do exactly that.
JacKTrocinskI 5y ago
Pretty sure Benford's law applies to images and can be used as a tool to detect fakes.
- MauranKilom 5y ago
  Interesting idea, but it's not obvious to me in what way you would apply it. For example, compositing two images that somehow obey Benford's law should result in something that also obeys it. Maybe you mean "Benford's law" as in "just general stastical properties", but I hope you had something more specific in mind.
hdm41bc 5y ago
Is this a solvable problem by requiring camera manufacturers cryptographically sign photos and videos created on those devices? If that’s in place then it seems like it could be the basis for chain of custody of journalistic images backed by a blockchain. This seems like the only viable solution to me since any AI powered solution would just be a cat and mouse game.
- kc0bfv 5y ago
  In this scenario, it would almost certainly have to be that manufacturers would have to build cameras that cryptographically sign the images and videos. The cameras would have to be able to have that ability, install of the manufacturers doing the signing. And then what would the Blockchain provide in this case? A chain of cryptographically signed certificates back to a manufacturer is basically the same system we use on the web today TLS certs. No Blockchain required. And a major problem with that system is making sure the camera only signs genuine images. A nation state actor, or even a large political operation, is going to have an incentive to bypass the protections on that camera - perhaps just driving what the CCD is telling the rest of the camera - so they can produce signed fakes. That's if they can't just get the private key off the camera, perhaps through a side channel attack - which can be pretty tough to pull off but is very tough to really defend against. Get a private key, game is over for the fraudster.
  - hdm41bc 5y ago
    The way I thought that the blockchain would be employed is to use it to track transformations of the image. Post-processing, adding captions, and what not. This would provide an audit trail of changes to the original source image. If, in fact, we can’t reliably sign the source image as authentic, then the rest of the system falls apart. It seems like this is the crux of the problem.
    - someguyorother 5y ago
      That seems to be a DRM problem. Let's say that you want the camera to track all modifications of the picture. Then, analogous to DRM, there's nothing stopping the forger from just replacing the CCD array on the camera with a wire connected to a computer running GIMP. To patch the "digital hole", it would be necessary to make the camera tamperproof, or force GIMP to run under a trusted enclave that won't do transformations without a live internet connection, or create an untamperable watermark system to place the transform metadata in the picture itself. These are all attempted solutions to the DRM problem. And since DRM doesn't work, nor would this, I don't think.
kkielhofner 5y ago
It's been really interesting to see another recent uptick in media (and HN) coverage of deepfakes, modified media, etc lately. There are virtually endless ways to generate ("deepfake") or otherwise modify media. I'm convinced that we're (at most) a couple advancements of software and hardware away from anyone being able to generate or otherwise modify media to the point where it's undetectable (certainly by average media consumers). This comes up so often on HN I'm beginning to feel like a shill but about six months ago I started working on a cryptographic approach to 100% secure media authentication, verification, and provenance with my latest startup Tovera[0]. With traditional approaches (SHA256 checksums) and the addition of blockchain (for truly immutable and third party verification) we have an approach[1] that I'm confident can solve this issue. [0] https://tovera.com https://tovera.com [1] https://www.tovera.com/tech https://www.tovera.com/tech
- tsimionescu 5y ago
  Block chain can at best give you chain-of-custody, but it can't help with the real problem - the original source. Trusting the original source requires, well, trust, so a block chain really adds very little to the solution.
  - kkielhofner 5y ago
    In our implementation the source/creator of the media is verified as well. I think of our approach as "Twitter blue checkmark meets certificates" (sort of). Of course a user can always take media and re-upload it via any number of ways but they can't do so as any other user. One of our next steps is to have identity verification by way of social media accounts and Stripe identity or another identity verification platform. The primary verification source is our API that interacts with a traditional data store. Blockchain only serves to add additional verification that we (or anyone else) isn't modifying or otherwise tampering with our verification record.
- kc0bfv 5y ago
  But this only works if all views of the images employ your client... If I download an image (screenshot if necessary), modify it, and host it myself, how does the system work then? And, unless all users trust only things viewed securely, and distrust things viewed nonsecurely (out of your client), then misinformation and fake photos can still propagate, right? (Or, how does the system handle this?)
dang 5y ago
Discussed at the time: Signs that can reveal a fake photo - https://news.ycombinator.com/item?id=14670670 https://news.ycombinator.com/item?id=14670670 - June 2017 (18 comments)
z5h 5y ago
I tried to prove that crops which do not preserve photographic centre are detectable https://physics.stackexchange.com/a/367981/3194 https://physics.stackexchange.com/a/367981/3194 This was after photographers seemed to not believe this was the case https://photo.stackexchange.com/q/86550/45128 https://photo.stackexchange.com/q/86550/45128 In any case, detecting cropped photos could be a way to detect that something has been intentionally omitted after the fact.
- deleted 5y ago
  [deleted]
- jobigoud 5y ago
  But cameras aren't perfect pinholes though. The center of the sensor and the optical axis of the lens are already not perfectly aligned, and the sensor is not necessarily perpendicular to the lens barrel. These distortions might be larger than any change of size due to an object being in the periphery of the field of view, especially for longer focal length where the rays are more parallel.
  - z5h 5y ago
    Correct. So, in theory it works and in practice it works with limitations. You could probably create a lens/camera calibration profile that could take the practical use further.
- lupire 5y ago
  cropping is 0.01% of what makes a misleading photo misleading. And content-aware fill can uncrop.
tinus_hn 5y ago
https://twitter.com/JackPosobiec/status/1434581638923620360?s=20 https://twitter.com/JackPosobiec/status/1434581638923620360?... These days you don’t even need to fake the photo, you can just attach the fake drama to a photo of something else and no one will bat an eyelid.
- sluggosaurus 5y ago
  All the mainstream reputable news organizations use stock photography extensively, so the public is generally willing to accept that the photograph attached to the headline needn't have anything to do with that headline. Personally, I think this practice should be ended or at least decreased greatly. An article about a ship doesn't a stock photograph of a ship. It probably doesn't even need a photograph about the particular ship the article is discussing, unless there is something visually unusual or notable about that ship. The formula "Ship A is late to port, here is a stock photo of Ship B" is basically worthless. I guess they're tossing a bone to the borderline illiterate who are stuck at the "I can read picture books" level of literacy? But generally articles themselves are written at a higher 'reading level' than that.
- Wistar 5y ago
  Snopes often refers to these as "miscaptioned."
  - 1cvmask 5y ago
    Unfortunately Snopes miscaptions many things themselves. Where the fact checkers of the "fact checkers".
    - dahart 5y ago
      Got some examples?
      - Wistar 5y ago
        None that I could find. I didn't know snopes was in the business of captioning at all.
open-source-ux 5y ago
There are also misleading photos - not fake images but a more subtle attempt to manipulate viewers. A mundane example: You're browsing a property website, look through the pictures, and then visit a property only to discover the rooms are tiny matchbox-sized spaces. They looked so much more spacious when you viewed them online. You're just discovered wide-lens-photography for real estate - purposely distorts or make a space look spacious. A 'fake' news example: During the coronavirus lockdown, a Danish photo agency, Ritzau Scanpix, commisioned two photographers to use two different perspectives to shoot scenes of people in socially-distance scenarios. Were people observing the rules? Or did the type of lens (wide-angle and telephoto) intentionally give a misleadling impression? The pictures are here - the article is in Danish, but the photos tell the story: https://nyheder.tv2.dk/samfund/2020-04-26-hvor-taet-er-folk-paa-hinanden-disse-billeder-er-taget-samtidig-men-viser-to https://nyheder.tv2.dk/samfund/2020-04-26-hvor-taet-er-folk-...
thesz 5y ago
Camera's often have non-linear radial image distortions. For example, OpenCV's camera calibration process computes these radial distortions along the way [1]. They may not be very significant, but they exist. [1] https://docs.opencv.org/master/dc/dbb/tutorial_py_calibration.html https://docs.opencv.org/master/dc/dbb/tutorial_py_calibratio... Aligning points on a photo outside of more-or-less linear center region will certainly result in crossing lines. Which we see in the alignment attempt there in the article - the points we align are close to center and close to edge (max distortion). There is no mention of distortions in the entire article. But some other points are interesting to think about.

83 points by hiddencache 5y ago

I wonder why the article has the title '20170629-the-hidden-signs-that-can...' in the url. That date would suggest it's from the 29th of june 2017 (while the date below the headlines says 2020), way before the current breakthroughs of deep fakes.

commoner 5y ago
Nice catch. The article was republished. Here's an archive from 2019 of the original 2017 version: https://web.archive.org/web/20191030232152/https://www.bbc.com/future/article/20170629-the-hidden-signs-that-can-reveal-if-a-photo-is-fake https://web.archive.org/web/20191030232152/https://www.bbc.c...
- hwers 5y ago
  I'll be honest and admit that in taking a second look I noticed that they totally admit to this being a republished article from earlier: "[...] BBC Future has brought you in-depth and rigorous stories to help you navigate the current pandemic, but we know that’s not all you want to read. So now we’re dedicating a series to help you escape. We’ll be revisiting our most popular features from the last three years in our Lockdown Longreads.[...]"
  - commoner 5y ago
    I didn't see that, either. My eyes glossed right over the italics.
  - dang 5y ago
    Still kind of dodgy not to include the original date, and to display today's date in exactly the same way that a publication date is usually displayed.
dang 5y ago
We've added the year to the title now. Thanks!

hk-im-ad 5y ago

With GANs, any fake image detection technique you could derive based on visual data could probably be learned by the discriminator given the right architecture choice.

Cthulhu_ 5y ago
It's an interesting rat race to see; you could make a fake image using AI, then a fake image detector software, then connect the two until the AI generates images no longer recognizable as fake.
- DonHopkins 5y ago
  Since so many people don't care about the truth, and LARP that they believe fake news and fake images just own the libs, maybe there's some money to be made by selling them fake fake-image-detector software like Hotdog Or Not: one app that always claims a photo is real, and another app that always claims a photo is fake. Or a single app with in-app-purchases that lets them pay to choose whatever they want to believe! https://www.theverge.com/2017/6/26/15876006/hot-dog-app-android-silicon-valley https://www.theverge.com/2017/6/26/15876006/hot-dog-app-andr...
- hwers 5y ago
  Just a comment: This usually isn't how GAN progress is made. I haven't really seen any GAN that incorporates advances in 'fake detection' directly into its discriminator. Usually it's just GANs getting more data and using smarter math and 'fake predictors' following the development by some 6-12 months.
- hk-im-ad 5y ago
  This is how a GAN works. There is a generator and a discriminator. The generator tries to fool the discriminator, and the discriminator tries to detect images generated by the generator. As one gets better, so does the other, until progress converges.

ChrisMarshallNY 5y ago

I remember this, when it was first published. Good article. One thing about fakes, is that they don't need to be super-high-quality, in many cases. They just need to be enough to reinforce a narrative to a receptive audience. An example is that Kerry/Fonda fake. Just looking at it as a thumbnail on my phone, it was easy to see that it was a composite. Also, I have seen both photos, in their original contexts. They are actually fairly well-known images, in their own rights. That didn't stop a whole lot of folks from thinking it was real. They were already primed. The comment below, about using an AI "iterative tuner" is probably spot-on. It's only a matter of time, before fake photos, videos, and audio, are par for the course.

wussboy 5y ago
I used to think that the internet would be the greatest tool for human peace ever invented. But I was wrong. I didn’t know that humans don’t use reason to determine their position. The use it to justify their position and Google provides the greatest tool ever built for allowing people to do exactly that.

JacKTrocinskI 5y ago

Pretty sure Benford's law applies to images and can be used as a tool to detect fakes.

MauranKilom 5y ago
Interesting idea, but it's not obvious to me in what way you would apply it. For example, compositing two images that somehow obey Benford's law should result in something that also obeys it. Maybe you mean "Benford's law" as in "just general stastical properties", but I hope you had something more specific in mind.

hdm41bc 5y ago

Is this a solvable problem by requiring camera manufacturers cryptographically sign photos and videos created on those devices? If that’s in place then it seems like it could be the basis for chain of custody of journalistic images backed by a blockchain. This seems like the only viable solution to me since any AI powered solution would just be a cat and mouse game.

kc0bfv 5y ago
In this scenario, it would almost certainly have to be that manufacturers would have to build cameras that cryptographically sign the images and videos. The cameras would have to be able to have that ability, install of the manufacturers doing the signing. And then what would the Blockchain provide in this case? A chain of cryptographically signed certificates back to a manufacturer is basically the same system we use on the web today TLS certs. No Blockchain required. And a major problem with that system is making sure the camera only signs genuine images. A nation state actor, or even a large political operation, is going to have an incentive to bypass the protections on that camera - perhaps just driving what the CCD is telling the rest of the camera - so they can produce signed fakes. That's if they can't just get the private key off the camera, perhaps through a side channel attack - which can be pretty tough to pull off but is very tough to really defend against. Get a private key, game is over for the fraudster.
- hdm41bc 5y ago
  The way I thought that the blockchain would be employed is to use it to track transformations of the image. Post-processing, adding captions, and what not. This would provide an audit trail of changes to the original source image. If, in fact, we can’t reliably sign the source image as authentic, then the rest of the system falls apart. It seems like this is the crux of the problem.
  - someguyorother 5y ago
    That seems to be a DRM problem. Let's say that you want the camera to track all modifications of the picture. Then, analogous to DRM, there's nothing stopping the forger from just replacing the CCD array on the camera with a wire connected to a computer running GIMP. To patch the "digital hole", it would be necessary to make the camera tamperproof, or force GIMP to run under a trusted enclave that won't do transformations without a live internet connection, or create an untamperable watermark system to place the transform metadata in the picture itself. These are all attempted solutions to the DRM problem. And since DRM doesn't work, nor would this, I don't think.

kkielhofner 5y ago

It's been really interesting to see another recent uptick in media (and HN) coverage of deepfakes, modified media, etc lately. There are virtually endless ways to generate ("deepfake") or otherwise modify media. I'm convinced that we're (at most) a couple advancements of software and hardware away from anyone being able to generate or otherwise modify media to the point where it's undetectable (certainly by average media consumers). This comes up so often on HN I'm beginning to feel like a shill but about six months ago I started working on a cryptographic approach to 100% secure media authentication, verification, and provenance with my latest startup Tovera[0]. With traditional approaches (SHA256 checksums) and the addition of blockchain (for truly immutable and third party verification) we have an approach[1] that I'm confident can solve this issue. [0] https://tovera.com https://tovera.com [1] https://www.tovera.com/tech https://www.tovera.com/tech

tsimionescu 5y ago
Block chain can at best give you chain-of-custody, but it can't help with the real problem - the original source. Trusting the original source requires, well, trust, so a block chain really adds very little to the solution.
- kkielhofner 5y ago
  In our implementation the source/creator of the media is verified as well. I think of our approach as "Twitter blue checkmark meets certificates" (sort of). Of course a user can always take media and re-upload it via any number of ways but they can't do so as any other user. One of our next steps is to have identity verification by way of social media accounts and Stripe identity or another identity verification platform. The primary verification source is our API that interacts with a traditional data store. Blockchain only serves to add additional verification that we (or anyone else) isn't modifying or otherwise tampering with our verification record.
kc0bfv 5y ago
But this only works if all views of the images employ your client... If I download an image (screenshot if necessary), modify it, and host it myself, how does the system work then? And, unless all users trust only things viewed securely, and distrust things viewed nonsecurely (out of your client), then misinformation and fake photos can still propagate, right? (Or, how does the system handle this?)

dang 5y ago

Discussed at the time: Signs that can reveal a fake photo - https://news.ycombinator.com/item?id=14670670 https://news.ycombinator.com/item?id=14670670 - June 2017 (18 comments)

z5h 5y ago

I tried to prove that crops which do not preserve photographic centre are detectable https://physics.stackexchange.com/a/367981/3194 https://physics.stackexchange.com/a/367981/3194 This was after photographers seemed to not believe this was the case https://photo.stackexchange.com/q/86550/45128 https://photo.stackexchange.com/q/86550/45128 In any case, detecting cropped photos could be a way to detect that something has been intentionally omitted after the fact.

deleted 5y ago
[deleted]
jobigoud 5y ago
But cameras aren't perfect pinholes though. The center of the sensor and the optical axis of the lens are already not perfectly aligned, and the sensor is not necessarily perpendicular to the lens barrel. These distortions might be larger than any change of size due to an object being in the periphery of the field of view, especially for longer focal length where the rays are more parallel.
- z5h 5y ago
  Correct. So, in theory it works and in practice it works with limitations. You could probably create a lens/camera calibration profile that could take the practical use further.
lupire 5y ago
cropping is 0.01% of what makes a misleading photo misleading. And content-aware fill can uncrop.

tinus_hn 5y ago

https://twitter.com/JackPosobiec/status/1434581638923620360?s=20 https://twitter.com/JackPosobiec/status/1434581638923620360?... These days you don’t even need to fake the photo, you can just attach the fake drama to a photo of something else and no one will bat an eyelid.

sluggosaurus 5y ago
All the mainstream reputable news organizations use stock photography extensively, so the public is generally willing to accept that the photograph attached to the headline needn't have anything to do with that headline. Personally, I think this practice should be ended or at least decreased greatly. An article about a ship doesn't a stock photograph of a ship. It probably doesn't even need a photograph about the particular ship the article is discussing, unless there is something visually unusual or notable about that ship. The formula "Ship A is late to port, here is a stock photo of Ship B" is basically worthless. I guess they're tossing a bone to the borderline illiterate who are stuck at the "I can read picture books" level of literacy? But generally articles themselves are written at a higher 'reading level' than that.
Wistar 5y ago
Snopes often refers to these as "miscaptioned."
- 1cvmask 5y ago
  Unfortunately Snopes miscaptions many things themselves. Where the fact checkers of the "fact checkers".
  - dahart 5y ago
    Got some examples?
    - Wistar 5y ago
      None that I could find. I didn't know snopes was in the business of captioning at all.

open-source-ux 5y ago

There are also misleading photos - not fake images but a more subtle attempt to manipulate viewers. A mundane example: You're browsing a property website, look through the pictures, and then visit a property only to discover the rooms are tiny matchbox-sized spaces. They looked so much more spacious when you viewed them online. You're just discovered wide-lens-photography for real estate - purposely distorts or make a space look spacious. A 'fake' news example: During the coronavirus lockdown, a Danish photo agency, Ritzau Scanpix, commisioned two photographers to use two different perspectives to shoot scenes of people in socially-distance scenarios. Were people observing the rules? Or did the type of lens (wide-angle and telephoto) intentionally give a misleadling impression? The pictures are here - the article is in Danish, but the photos tell the story: https://nyheder.tv2.dk/samfund/2020-04-26-hvor-taet-er-folk-paa-hinanden-disse-billeder-er-taget-samtidig-men-viser-to https://nyheder.tv2.dk/samfund/2020-04-26-hvor-taet-er-folk-...

thesz 5y ago

Camera's often have non-linear radial image distortions. For example, OpenCV's camera calibration process computes these radial distortions along the way [1]. They may not be very significant, but they exist. [1] https://docs.opencv.org/master/dc/dbb/tutorial_py_calibration.html https://docs.opencv.org/master/dc/dbb/tutorial_py_calibratio... Aligning points on a photo outside of more-or-less linear center region will certainly result in crossing lines. Which we see in the alignment attempt there in the article - the points we align are close to center and close to edge (max distortion). There is no mention of distortions in the entire article. But some other points are interesting to think about.