Identifying Manipulated Images 162
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.
No ads, all on one page (Score:5, Informative)
http://www.technologyreview.com/printer_friendly_article.aspx?id=20423 [technologyreview.com]
Limited utillity (Score:3, Informative)
Re:Colombo did this on his 1970's TV show (Score:-1, Informative)
Re:Expert User Required (Score:5, Informative)
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.
Re:No ads, all on one page (Score:4, Informative)
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:
Re:That should help (Score:3, Informative)
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]
Found the episode (Score:4, Informative)
Re:That should help (Score:5, Informative)
As one of my instructors used to say, "I don't know what I like but I know what art is."
-mcgrew
Faked non-uniformly lit (Score:1, Informative)
Re:Steganography (Score:3, Informative)
Most image steganography isn't that great, though, and steganography by a well-known means of cleartext data is fairly pointless.
Another good tool for detecting photoshopping (Score:3, Informative)
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]
Voodoo software (Score:1, Informative)
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.