Quite a few eclectic sports photographers profile the noise profiles of their cameras all of the time with several applications such as NoiseNinja, Noiseware, or pre-programmed profiles built into various RAW converters such as C1-Pro, Pixmantic RawShooter, or Adobe Camera Raw / DNG Converter. It is well known that a given camera model has a paticular 'look' to its noise characteristics. Their goal is to remove / hide / blur the noise their camera naturally produces so they can have a nice smooth image of an athlete catching a football, etc. (they say it prints better...I run grainy B&W images in dungeons known as gyms in the newspaper just fine though). Personally I think a few people take it too far producing images that definately look unrealistic and blotchy...but that's another story...

As far as taking an arbitrary image from the internet and figuring out whose camera took it...you're generally working with a 640x480 pixel image that was produced by resizing a 2560x1920 pixel image. It is 4x smaller in each dimension than the original image, so you're working with 1/16th the original surface area of the image, or about 6.25% of the original image. The rest of the data was dropped, and whatever emerges is just an estimation from combining neighboring pixels. In short, noise is hidden, and you'll be hard-pressed to get very far in figuring out whose camera took the picture...



Basically there are many ways to 'hide' a paticular camera's signature. This software doesn't take an arbitrary image on the Internet and determine whose camera it was taken with (there's too many cameras out there, too few pixels in an image posted online). What it does is let you take your digital image and your camera to court, and show (hopefully beyond a resonable doubt) that your image's content was not edited in photoshop after taking the picture, ie., that the image was taken with that camera.

And on the scenario proposed by the article (which is a shocking scenario, though I don't see anything authoritive saying it was actually used in such a case)...by the time law-enforcement confiscates stuff, I have no idea how much impact saying "it was taken with this camera" has when there is probably already a mountain of evidence showing that the crime(s) took place. I'd imagine that other evidence for the most part would say the same thing. But it is nice to think that this kind of analysis will one day be used to further prove beyond a shadow of a doubt that the guilty are infact guilty of their crime(s).