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Identifying Manipulated Images: New tools that analyze the lighting in images help spot tampering
Technology Review (MIT) ^ | March 17, 2008 | Erica Naone

Posted on 03/17/2008 11:15:29 AM PDT by Stoat

Identifying Manipulated Images

New tools that analyze the lighting in images help spot tampering.

By Erica Naone

 
True or false? The tool used above spots whether an image has been manipulated by modeling the lighting in the image based on an analysis of visible surfaces. To analyze an image, a user indicates the surfaces to consider using contour lines (shown above in white). The system checks for inconsistencies in the way that those surfaces are lit.
Credit: Micah Kimo Johnson, Hany Farid

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 Northeastern University and author of a book on digital forensics, is familiar with both Krawetz's and Farid's work. She says that digital forensics is a new enough field of research that even the best tools are still some distance away from being helpful to a general user. In the meantime, she says, "it helps to be on the alert." Baron notes that, while sophisticated users could make fraudulent images that would evade detection by the available tools, many manipulations aren't very sophisticated. "It's amazing to me, some of the things that make their way onto the Web and that people believe are real," she says. "Many of the things that software can point out, you can see with the naked eye, but you don't notice it."

Johnson says that he sees a need for tools that a news agency, for example, could use to quickly perform a dozen basic checks on an image to look for fraud. While it might not catch all tampering, he says, such a tool would be an important step, and it could work "like an initial spam filter." As part of developing that type of tool, he says, work needs to be done on creating better interfaces for existing tools that would make them accessible to a general audience.



TOPICS: Business/Economy; Miscellaneous; News/Current Events; Technical
KEYWORDS: fauxtography; manipulation; photographs; photography; photoshop; photoshopping; tech; techping
Please also see the Comments area at the article's original page where the Author as well as Dr. Neal Krawetz are answering reader questions.
1 posted on 03/17/2008 11:15:31 AM PDT by Stoat
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To: Stoat; ShadowAce

Bump


2 posted on 03/17/2008 11:18:00 AM PDT by Fiddlstix (Warning! This Is A Subliminal Tagline! Read it at your own risk!(Presented by TagLines R US))
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To: ShadowAce

Ping


3 posted on 03/17/2008 11:18:21 AM PDT by Stoat (Rice / Coulter 2012: Smart Ladies for a Strong America)
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To: Stoat

I hope they take a historical look at all of AP’s evil Israel/pro-Palestinian photos.


4 posted on 03/17/2008 11:19:02 AM PDT by SengirV
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To: Stoat
He was really there! I promise.


5 posted on 03/17/2008 11:21:04 AM PDT by dead (I've got my eye out for Mullah Omar.)
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To: Stoat
Johnson says that he sees a need for tools that a news agency, for example, could use to quickly perform a dozen basic checks on an image to look for fraud. While it might not catch all tampering, he says, such a tool would be an important step, and it could work "like an initial spam filter."

Should be standard issue for AP and Reuters as well as Google News.

6 posted on 03/17/2008 11:22:46 AM PDT by anymouse
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To: dead

7 posted on 03/17/2008 11:22:53 AM PDT by evets
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To: dead

ROTFLMAO!!!!!


8 posted on 03/17/2008 11:23:53 AM PDT by Stoat (Rice / Coulter 2012: Smart Ladies for a Strong America)
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To: Stoat; glock rocks

Ping...


9 posted on 03/17/2008 11:23:54 AM PDT by tubebender
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To: SengirV
I hope they take a historical look at all of AP’s evil Israel/pro-Palestinian photos.

Green helmet guy will be "famous" if they do.

10 posted on 03/17/2008 11:24:41 AM PDT by beltfed308 (Heller: The defining moment of our Republic)
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To: Stoat

But a tool could be created to analyze an image and correct anything that these tools look at to detect fake images...thus rendering the tools useless.


11 posted on 03/17/2008 11:25:15 AM PDT by Bobalu (I guess I see'd that varmint for the last time....)
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To: Stoat

In related news, NASA announced today that all images of moon landings have been archived and secured under the Homeland Security Act...


12 posted on 03/17/2008 11:26:23 AM PDT by Old Professer (The critic writes with rapier pen, dips it twice, and writes again.)
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To: Stoat; Registered

Good post Stoat


13 posted on 03/17/2008 11:27:04 AM PDT by stainlessbanner
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To: Stoat

14 posted on 03/17/2008 11:29:08 AM PDT by evets
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To: evets
 Photobucket


"snicker"

15 posted on 03/17/2008 11:36:08 AM PDT by Stoat (Rice / Coulter 2012: Smart Ladies for a Strong America)
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To: evets
No, Ms. Rice is not a Goa'uld.

Ms. Clinton ...

16 posted on 03/17/2008 11:38:07 AM PDT by ArrogantBustard (Western Civilization is Aborting, Buggering, and Contracepting itself out of existence.)
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To: Bobalu

Yes, but another tool could then be created to detect the corrections.....usw ( a little German abbreviation there)


17 posted on 03/17/2008 11:44:11 AM PDT by Postman
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To: dead

Awesome.

BTW, the AP is screwed.


18 posted on 03/17/2008 11:44:45 AM PDT by snowrip (Liberal? YOU ARE A SOCIALIST WITH NO RATIONAL ARGUMENT.)
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To: Bobalu
But a tool could be created to analyze an image and correct anything that these tools look at to detect fake images...thus rendering the tools useless.

I suppose we could be looking at a tech war of sorts with competing R&D efforts....one side continuously working on technologies to identify manipulated photos and others trying to circumvent those efforts.  Sounds much like internet / computer security R&D in general.  In that arena, we have an ongoing war with neither side giving up and both sides claiming victories at one point or another, and all the while the end-user public is hoping that they are being adequately protected   :-)

19 posted on 03/17/2008 11:45:30 AM PDT by Stoat (Rice / Coulter 2012: Smart Ladies for a Strong America)
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To: stainlessbanner
Good post Stoat

Thank you for your kind words  :-)

These technologies could conceivably put a real dent in the Left's favored spin methodologies....if they can't lie with images anymore, they haven't got much else  :-)

20 posted on 03/17/2008 11:51:09 AM PDT by Stoat (Rice / Coulter 2012: Smart Ladies for a Strong America)
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To: SengirV
I hope they take a historical look at all of AP’s evil Israel/pro-Palestinian photos.

Around the time they start doing something like that, the techs who run the photo analysis software will find their homes randomly blowing up......

21 posted on 03/17/2008 11:57:09 AM PDT by Stoat (Rice / Coulter 2012: Smart Ladies for a Strong America)
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To: Stoat

BUMP!


22 posted on 03/17/2008 12:03:32 PM PDT by Publius6961 (MSM: Israelis are killed by rockets; Lebanese are killed by Israelis.)
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To: Stoat

Good! Now we can find out if all those Loch Ness pictures are real or not.


23 posted on 03/17/2008 12:08:21 PM PDT by McKayopectate
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To: Stoat
Dan Rather is scared sh*tless because he's heard there's a version in beta that can do the same for news broadcasters...
24 posted on 03/17/2008 12:31:28 PM PDT by Dr.Zoidberg (Mohammedanism - Bringing you only the best of the 6th century for fourteen hundred years.)
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To: Stoat

Fakers will just use this software on their productions to see if it passes the test.
If it fails, they will work a little longer until it passes.
Also, this sort of logic can be incorporated into image-processing software so that it will flag anything that is inconsistent.
Big breakthrough? No.


25 posted on 03/17/2008 12:31:49 PM PDT by Leftism is Mentally Deranged
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To: Stoat
Sometimes, it takes an expert...


26 posted on 03/17/2008 12:35:41 PM PDT by reagan_fanatic (feh)
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To: reagan_fanatic

LMAO! Is that a half-eaten bagel flying out of his mouth?

Or a half-eaten bagel being thrown at him?

“snicker”


27 posted on 03/17/2008 1:12:14 PM PDT by Stoat (Rice / Coulter 2012: Smart Ladies for a Strong America)
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To: rdb3; Calvinist_Dark_Lord; GodGunsandGuts; CyberCowboy777; Salo; Bobsat; JosephW; ...

28 posted on 03/17/2008 5:33:18 PM PDT by ShadowAce (Linux -- The Ultimate Windows Service Pack)
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To: reagan_fanatic; Stoat; mikrofon; Charles Henrickson
Photobucket

Analyze *this*.

29 posted on 03/17/2008 5:37:55 PM PDT by martin_fierro (I'M NOT DEAD YET!)
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To: dead

Reuters, is that you?


30 posted on 03/17/2008 5:38:35 PM PDT by The Spirit Of Allegiance (Public Employees: Honor Your Oaths! Defend the Constitution from Enemies--Foreign and Domestic!)
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To: martin_fierro; dead; Tijeras_Slim; mikrofon; PJ-Comix

I dunno, something strikes me funny about this photo. . . .

31 posted on 03/17/2008 5:58:26 PM PDT by Charles Henrickson (Can't put my finger on it. . . .)
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To: martin_fierro; mikrofon

This one, too, like somehow it's been . . . oh, manipulated. . . .

32 posted on 03/17/2008 6:03:44 PM PDT by Charles Henrickson (Can't put my finger on it. . . .)
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To: Charles Henrickson; martin_fierro

"I have never .. tampered .. with any .. photos -- Mr Henrickson..."

33 posted on 03/17/2008 6:50:25 PM PDT by mikrofon (*CERTIFIED* Original)
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To: martin_fierro
Analyze *this*.

LMAO

It actually doesn't take a whole lot of stretching and manipulation to get ol' Waxman to change from his 'normal' ghoulish self into a full-fledged gargoyle, does it?

hehe

34 posted on 03/17/2008 6:58:10 PM PDT by Stoat (Rice / Coulter 2012: Smart Ladies for a Strong America)
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To: ShadowAce

Thank you very much for pinging your list :-)


35 posted on 03/17/2008 6:59:30 PM PDT by Stoat (Rice / Coulter 2012: Smart Ladies for a Strong America)
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To: Stoat
Darn, why did JimRob kick Registered out of Free Republic when we needed him the most?

Can you guess what he would do with this subject?

36 posted on 03/17/2008 7:01:48 PM PDT by Hunble
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To: martin_fierro

Now that’s no way to treat a perfectly good Bat Boy.


37 posted on 03/17/2008 7:04:19 PM PDT by JoJo Gunn (Help control the RINO population. Have them spayed or neutered. )
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To: Hunble
Darn, why did JimRob kick Registered out of Free Republic when we needed him the most?

Well, his last post sums it up and he asked for his account to be closed.

Posts by Registered

Can you guess what he would do with this subject?

Although it's always a shame when talented, artistic people leave for any reason, I think that we have a number of currently active and spectacularly talented Image Wizards who keep us laughing while we're being informed....several have honored us by posting to this thread


38 posted on 03/17/2008 7:15:27 PM PDT by Stoat (Rice / Coulter 2012: Smart Ladies for a Strong America)
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To: Stoat
Now lets be a little more honest here....

JimRob and Registered were fighting because he supported Rudy Giuliani. You know it, and I know it.

What a horrible waste of an outstanding talent!

As we look back, that argument sounds so silly now.

39 posted on 03/17/2008 7:28:01 PM PDT by Hunble
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To: Stoat
Now lets be a little more honest here....

JimRob and Registered were fighting because he supported Rudy Giuliani. You know it, and I know it.

What a horrible waste of an outstanding talent!

As we look back, that argument sounds so silly now.

40 posted on 03/17/2008 7:28:26 PM PDT by Hunble
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To: Hunble
Now lets be a little more honest here....

JimRob and Registered were fighting because he supported Rudy Giuliani. You know it, and I know it.

Was I being "dishonest" merely because I didn't recount something here that's easily read by clicking the link that I provided?  I merely didn't want to go so very far off-topic, and I didn't see the point..

As we look back, that argument sounds so silly now.

Most online political arguments ultimately become silly because all too often people become overheated and end up shouting so loudly that nobody is listening to anybody else, IMHO

41 posted on 03/17/2008 7:35:48 PM PDT by Stoat (Rice / Coulter 2012: Smart Ladies for a Strong America)
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To: Stoat
I merely didn't want to go so very far off-topic...

Agreed!

But dang, Registered would have had a so much fun with this topic!

42 posted on 03/17/2008 7:41:52 PM PDT by Hunble
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To: Stoat

You mean this pic of the Pittster at his watering hole might not be genuine?

43 posted on 03/18/2008 8:42:00 AM PDT by steve-b (Sin lies only in hurting others unnecessarily. All other "sins" are invented nonsense. --RAH)
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