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How Photoshopped Is That Picture?
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.'"
It also uses advanced neural-network powered learning algorithms to allow it to also leverage "having seen a a great many shops".
I wonder.... will it be fooled if images are converted to/from lossy formats a few times.....
.nosig
If it did the analysis using just the "after" image (maybe by looking statistically at ithe ndividual pixel level, I dunno I'm not an image expert) that software would be SO useful for Internet dating sites! ;)
Actually I'm wondering if images CAN be analyzed using statistical data from the individual pixel data to determine things like what camera was used to take the picture, maybe what software was used to edit/convert it (using gamma curves?). Then you could see (maybe) who was posting pictures of themselves from long ago (not like I've ever done that!).
My copy of The Commissar Vanishes. Of course, the author presents original photos of Stalin with Large group, smaller group, all by his lonesome at one point and you can examine the technique used for filling in background. Also, photos where someone was added (Comrade is now in favor, include with Stalin at glorious parade!)
As for Photoshop Disasters, there's a website and the checkout aisle for that sort of mental exercise.
A feeling of having made the same mistake before: Deja Foobar
... because THAT story title quite obviously is not in compliance with Adobe's Permissions and trademark guidelines!
Next time, better talk about images being "GIMPed". Just to be safe and all that ;)
:%s/Open Source/Free Software/g
YTARY!
Yeah, it shouldn't be that hard to uncrop a picture.
By no means would I consider myself a professional re-touch artist, but I am familiar with the techniques and have produced a few works that were high enough quality for advertising and magazines.
I gotta say, the amount of work that goes in to even the meanest image is staggering. An acquaintance of mine does interior photography for commercial real estate and multi-unit dwellings (apartments, condos, etc.) and while his photography is top notch to begin with, his re-touching is on another plane all together.
He was excited when Photoshop got an upgrade in CS5 to handle more layers because he was routinely bumping up against the limit in CS4. Usually, his work flow consisted of him selecting and making a separate layer for every surface that had a different texture or zone of light, then manually adjusting the levels to bring the brightness and contrast to where he wanted. While tedious and mind-numbing, the over all effect is beautiful true High Dynamic Range images.
Not likely. When you airbrush, you're destroying the original data. That's why you can detect the change; it no longer has the same fringing around areas of contrast, the noise levels don't quite match, the gradients don't look exactly the same, the reflections of lighting are subtly off, etc. There's nothing to restore because the original information is gone. The best you could do is highlight the areas that were altered. Maybe, if you were lucky, you might be able to approximately reverse a virtual tummy tuck by showing where the moved portions probably were originally, then leaving a gap where content was elided, but that's kind of the exception rather than the rule.
What would be more entertaining would be if someone took this algorithm, then rewrote it (or wrote a parallel successive approximation algorithm to feed into it) so that it generates photos that, although heavily doctored, pass this test. Put another way, this sort of methodology is only effective if the details are kept secret....
Check out my sci-fi/humor trilogy at PatriotsBooks.
You mean they're promoting a law that would make Victoria's Secret disclose the endless belly-fold-tucking and (B to D) breast enlargements they love so much? As a doc, looking at those anatomically-impossible bodies it makes me sad, because they change our perception of what should be seen as attractive to a standard that is literally impossible to meet. And at times even I have caught my own perceptions as being skewed, despite knowing full well how it happened.
I must admit I grew up in an environment where I was not that exposed to media, be it TV or magazines.
But once a magazine came my way, my thoughts wondered as to what the beauties in the magazines ate! They looked so beautiful...with no "flaws", (for lack of a better word).
In adulthood, I left my community for the big city, hoping to get a good job and to also see the "beauties" on the streets. I must say I was, and still continue to be disappointed. In the decades I have been in the big city, I have not met a single beauty once! Never!
The ones I see on TV and in the magazines are all "fake!" Needless to say, I returned to my old small town, found a real woman and have never regretted it. I have also asked her to show me one beauty if she comes across one if we're together. It's never happened.
Sadly, the practice of photoshopping is damaging our daughters' and sons' self esteem, with eating disorders that have only gotten worse. Sad, sad indeed.
It's certainly interesting, but also pointless. I mean, if you don't know that anything out of Hollywood is heavily retouched then you're embarrassingly naive. And even before photos are loaded up in Photoshop the celebrity has already been loaded up with a pound of makeup, sat under carefully positioned lights and been photographed by a professional. That's why those sexiest people lists are so stupid. Almost anyone subjected to that amount of effort will look great.
It's like those stupid articles where some celebrities fitness "secrets" are revealed. I'll tell you what their secrets entail: enjoy an immense amount of leisure time, make it your job to look good and pay a fitness trainer six figures to accomplish that.
American society is more influenced by the entertainment industry than any other culture on Earth.
I bet the people on CSI can uncrop a picture. ;)
If I were God, wouldn't I protect my churches from acts of me?
You actually can uncrop some images, as some image formats/applications save a thumbnail in the metadata and that thumbnail might not be updated properly if the image gets edited, leaving a low-res original in place. Other images formats like JPEG allow you to uncrop up to 7 pixel around the image, as the format only supports width/height that is a multiple of 8, thus the crop to the final image size happens at the decoding stage and data might be left over (depends however on the encoder).
While interesting, it will not be of much use with professional photographs.
I'm a pro photographer and used to program in Assembly, C and Forth. The way I hide the "life experience" of older women is to use specialized lighting. Small point lights create sharp shadows in skin folds, causing the subject to look extremely old. Very large lights might leave no shadows at all because the light wraps all sides of the skin fold. To achieve this, I use a 7 foot diameter Octobox - a light modifier that creates a huge soft light source. I also use a lens that focuses red light on a different plane than green and blue. The net effect is to soften skin, as blemishes will not be in sharp focus. The camera does not record JPEG, but saves raw sensor data that is later converted into a picture using Photoshop or Lightroom.
Thus as far as software can tell, the JPEG photo produced is the original. There are no re-compression artifacts. In fact, until the RAW sensor data was "de-mosaiced" in Photoshop, one could argue that the picture did not exist as such. And most of the smoothing of the image takes place in the analog world, before a digital file is produced.
Place nail here >+
I recently got a tiny point-and-shoot camera, a Canon ELPH 300 HS, and I've been participating in CHDK's effort to hack it. When we got RAW support working, I learned the camera's lens actually has severe barrel distortion that gets "corrected" in software before saving a JPEG.
Images are "shopped" before they even emerge from the camera these days.
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.
Check out my sci-fi/humor trilogy at PatriotsBooks.