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Identifying Manipulated Images
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.
Does it also apply to steganography? Would sort of suck if it did.
People who manipulate images will use these tools for quality control: When the fabrication passes all tests, it is ready to be released.
Duh!
this post is now diamonds!
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 from Slashdot in August 2007.
I can tell just by looking at the pixels and cause ive seen a lot of 'shops.
The printer-friendly version:
http://www.technologyreview.com/printer_friendly_article.aspx?id=20423
with all those UFO hoax photos then... /I want to disbelieve
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
Never trust a man wearing a coat and tie!
This bodes ill for all those geeks out there with "out-of-state" girlfriends!!
How amazed would you be to suddenly find that you just forgot what I wrote and you needed to reread my post.... again.
Now we can analyze those fake moon landing pictures.
...and then the photoshoppers will write evolutionary algorithms to modify their photographs until they pass evaluation by this tool.
this method is way better
Forensic Analysis Reveals Al-Qaeda's Image Doctoring
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.
TCAP-Abort
I can tell, look at the pixels, they look a bit off plus I've seen many shops in my time.
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.
I can tell from some of the pixels and from seeing quite a few shops in my time.
Circumcision is child abuse.
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.
Better known as 318230.
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 software.
You could even use the same codebase. If a particular method is using light-sources/shadow/etc to determine the authenticity of an image, then you could plot those same light-sources and have a plugin modify the image to be what the authentication plugin would expect.
Does the "image" contain Lindsey Lohan, Paris Hilton, Hillary Clinton or Sarah Michelle Gellar? It's photochopped.
``Tension, apprehension & dissension have begun!'' - Duffy Wyg&, in Alfred Bester's _The Demolished Man_
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!).
I record my sleeptalking
Adblock - everyone should have this installed.
I can tell from some of the pixels and from seeing quite a few shops in my day
Columbo and the Murder of a Rock Star, 1991 and yes Dabney Coleman was the bad guy.
Never trust a man wearing a coat and tie!
http://www.technologyreview.com/printer_friendly_article.aspx?id=20423 Enjoy :)
bash: rtfm: command not found
nt
Freedom isn't free; its price is the well-being of others.
I have written code that does the opposite.
I have shape generating program (wire frame sphere distortions) I developed. I wanted to add shading to the shapes. So I pick a point for the light source at random and color the pixels closer to the light a little brighter than those pixels farther away from the light. Really works well.
Once I got that working, I wanted to add self-cast shadows. You know, when the generated shape twists back on itself and should cast a shadow onto itself. Never got there, still sits in my code archives as just a "cool dealie".
Shouldn't be too hard to work my code backward and calculate (or guess) where lighting is coming from. I mean heck, I am one guy and this isn't so hard.
- I live the greatest adventure anyone could possibly desire. - Tosk the Hunted
Sorry for the subject line, but...
if you have enough information to test it, then you have enough information to fake it (at least well enough to pass the test).
It's better to be the foot on the boot than the face on the pavement. ~~ tkx Kadin2048
If you analyzed the noise pattern of the image, any edits would be obvious - the noise pattern wouldn't exist over edited components.
--Thomas J. Owens
The tool doesn't tell you if a photo is faked, it just analyzes whether there are light sources in the image that are not affecting different objects in the image the same way. From what I can tell it tries to tell if the way the light hits different objects in the picture "agree" with one another based on the position of the object, color, and probably other attributes not detailed in the article. If the photographer is controlling the light at all, using off-camera flash, focusing their light on some parts and blocking it from others, etc, then there would be components of the image that deliberately don't match when it comes to the lighting. People do that all the time, both deliberately and accidentally, when lighting a photo. Because the photographer has deliberately put a light on the subject that isn't hitting other elements, background, objects, the same way as it's hitting the subject. So it seems like the analysis would work great for cases where the light is ambient, and should affect all objects in the frame relatively the same. Otherwise it'd have a bad day.
Title on previous post should have read "Faked vs. non-uniformly lit"
You all suck at Photoshop.
No, really, you do.
Sig this!
Time to run the test on the Apollo shots, for all the tinfoil hats.
Or, with most dumb$*@&s who like to play off photoshopped images as real,
$ strings pic.jpg | grep -i photoshop
It is pitch black. You are likely to be eaten by a grue.
Anyione else notice the tyipo?
Who would win this election: Andrew Weiner vs Andrew Weiner's weiner.
did anyone else catch the blog in the new york times about the fenton photographs?
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, 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
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
I'm assuming he was trying to say silver bullet. Do we blame the professor, or the journalist?
You are awash in a sea of fiercely stated opinions. Obvious exits are: 'File->Quit', 'Reply', and 'Page Down'.
How are we to define "manipulation?"
Gamma adjustment and color correction. Dodging and burning. Red-eye and dust removal. Cropping. JPEG or other data compression. Dynamic range compression.
The only non-manipulated image is the raw data from the sensors. This is actually an improvement over film, where developing techniques can have quite an impact on the negatives - in film photography, there are no un-manipulated images.
Any serious news bureau should provide their raw images to interested parties. Only this way can their customers (us!) tell how much manipulation an image has undergone.
Taco, I will try not to make the obvious "anal" jokes, but FFS, is clicking spellcheck really so hard?
Now a method to refute all those "moon landing never happened" conspiracy theorists.
...is that Keith Richards actually looks like that? Without any enhancements at all?
WARNING: Smartphones have side effects--most of them undocumented.
So, are the Mars photographs from NASA doctored or what?!
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
Compresion analysis tool:
http://www.blackhat.com/presentations/bh-dc-08/Krawetz/Extra/jpegquality.c
If you can tell it was photoshopped, then someone isn't doing their job correctly.
I work for a photography lab, and we retouch problematic images. However, we call photoshop a dark art, and/or voodoo, because when it is done correctly, then no one knows that reality was any different. In other words, the person that had the portrait done thinks that it was a true representation of what they saw.
If someone even thinks to ask if we used photoshop during the processing of the image, then we failed.
Oh, and by the way, we refer to ANY image manipulation tool as photoshop. We use several other products. The owner of the company has looked at lunix every year as a possible way of cutting costs on workstations, and every year it is still the same. Linux is not compatible with color calibration hardware such as the spyder3 or eye one. A workstation that does not show accurate color on the monitor is of no use to us no matter what the software does.
When did "photoshop" become a verb?
This post has been gimped by the gimper
There is no reasonable defense against an idiot with an agenda
:wq
...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
~REZ~ #43301. Who'd fake being me anyway?
As an unrelated sidenote, Hacker Factor features a very interesting javascript that guesses the gender of the author of a block of text (>300 words). Thus far, I've found it to be eerily accurate.
Of course I didn't RTFA.
send your work to errol morris. he is sure to use the data and give you a shout out
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
GIMP
slashdot, now with 60% more troll!
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.
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 being trusted to sell my work. If I can't be trusted, I can't get jobs. So beyond my personal ethics paying respect for professional ethics, I have financial incentive not to make shit up.
But alas, as newsrooms shrink their staffs and call out for less freelance work, my as-true-as-I-can-humanly-make-them photographs will be left to go by the wayside in favor of hand-outs from people and organizations who have no incentive to follow the ethical rules AND an interest in making themselves look good.
I guess that's why I find myself photographing more weddings and corporate/advertising pieces. Oddly enough, they are clients who EXPECT to be lied to with heavily retouched photos.
And for the record, it is my professional opinion that this software won't make a bit of difference.
Any of you guys work for international media companies that are looking for America-based freelance contributors? I know a lot of the overseas media still looks for truth in reporting.
Message contains 1 attachment: spam.gif
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
And having seen quite a few 'shops in my time...
you had me at #!
The "tool" described in the article is a joke and reminds me of one (that also got posted on Slashdot, some time ago) whose author claimed to be able to tell if an image was a composite of several sources by "analyzing the compression patterns". Turned out all his tool did was check the quantization level of JPEG macroblocks... which is always defined by the last encoding. In other words, all it did was detect which parts the (last) encoder has decided to compress more, and which parts it had decided to compress less. Basically it worked like a (really bad) edge detection filter.
The description of the "tool" in this article is just as nonsensical. If a pixel is brighter than its neighbor, that tells you nothing about the position of the light source. If you want to determine that, you need to do some very complex spatial analysis, like the stuff done by Paul Debevec (and it's still only an approximation).
Human eyes and brains are much better at spotting lighting inconsistencies than any algorithm, because they can fill in 3D information from 2D images (which you simply cannot do without a powerful interpretative visual system). This tool (which, as the article states "has not been peer-reviewed" - what a surprise!) is just a hack put together to impress some wannabe "security consultants" and get a fat check for a quick patent buy-out.
There's another interesting method for detecting "photoshopped" images that were manipulated using the clone tool.
The procedure uses a Discrete Fourier Transform on a bunch of little sections of the image and tries to find groups of matching sections that are displaced in the same way. There're a few discussions and papers about the copy-forge detection procedure and there's also source for the proof-of-concept application.
I don't understand what use this program will have considering that the usage of fill lighting, either by flash or by reflectors, is a pretty standard practice before things even get to the photoshop stage.
At least it will hopefully put a stop to the horrendous movie posters I'm seeing like "The Accidental Husband" and "Over Her Dead Body". The photoshop job in these are SO BAD it makes me physically ill to look at them.
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").
There are three kinds of lies: lies, damned lies, and statistics.