How Photoshopped Is That Picture? 226
Freddybear writes "Digital forensics experts at Dartmouth have developed software that can analyze digital photos to rate how drastically they have been altered by digital editing techniques. 'The Dartmouth research, said Seth Matlins, a former talent agent and marketing executive, could be "hugely important" as a tool for objectively measuring the degree to which photos have been altered.'"
Re:Too bad this requires a "before" picture (Score:3, Informative)
It's a hard problem, just because a photo looks photoshopped doesn't necessarily mean that it was. These days one can shoot in RAW or TIF which makes the compression artifacts that used to be helpful non-existent. And ultimately somebody that's willing to put the time and effort into the work is probably going to be able to make it so that it fools the software most of the time.
Re:Too bad this requires a "before" picture (Score:2, Informative)
Re:Too bad this requires a "before" picture (Score:4, Informative)
TFA's link appears to be slashdotted, so I can't tell if they're using a similar technique or not.
Re:Too bad this requires a "before" picture (Score:4, Informative)
Re:It Can Tell by the Pixels (Score:5, Informative)
The whole term is dumb. You don't photoshop something in GIMP, for instance... just like you don't xerox on a Cannon.
http://dictionary.reference.com/browse/xerox [reference.com]
noun 2. ( sometimes lowercase ) a copy made on a xerographic copying machine.
verb (used with object), verb (used without object) 3. ( sometimes lowercase ) to print or reproduce by xerography.
See also: http://dictionary.reference.com/browse/photoshop [reference.com] — vb , -shops , -shopping , -shopped ( tr ) to alter (a digital photograph or other image), using an image editing application, especially Adobe Photoshop
Notice it says especially, not exclusively.
My point is that you most certainly do photoshop something in G.I.M.P..
Re:/. being sued in 3, 2, 1... (Score:3, Informative)
The best part of that is their suggested replacement for "Photoshopped", which is "enhanced with Adobe® Photoshop® Elements software." This has several problems:
As always, caveat emptor. IANALBIPOOSD.
Re:Having a little experience here (Score:5, Informative)
Most DSLRs have "HDR" capabilities. I know that on Nikon it is called bracketing and you can take three or four images with up to a 2 EV increase or decrease on on either side. That still only gives the image out of your camera 10 - 12 EV of range, which bumps right up against what most monitors are capable of displaying.
Re:Celebrity culture... (Score:5, Informative)
Indeed. Dove Evolution video clip [youtube.com]
Re:Revert? (Score:5, Informative)
Creating a Photoshop job that will fool even a sophisticated human eye is easy. Creating one that will fool an algorithm is very, very hard. The modification detection algorithms I remember hearing about start by taking a series of test images with the specific camera that was used to take the picture. In order to beat them, among other things, you'd need to:
...mathematically compute the probability of noise for each subpixel and adjust your noise so that the distance of each pixel from the mean of nearby pixels in areas of low contrast is close enough to what would be expected for that particular spot on that particular CCD at a particular physical temperature, and so that the noise level is consistent with the expected noise for a single physical temperature value across the entire image.
Alternatively, if a particular camera gets hot spots on parts of the chip when shooting lots of pictures in a row, the noise level might need to be a very complex gradient with the hot spots in particular places on the chip.
And so on. It's not a case of artistic training. It's a case of spending months modeling a single camera in MatLab. Not a single model. A single camera.
Re:tiff != lossless (Score:4, Informative)
TIFF = Thousands of Incompatible File Formats.