Digital Photos Give Away a Camera's Make and Model

holy_calamity writes "Engineers at Polytechnic University Brooklyn have discovered that digital snaps shorn of any metadata still reveal the make and model of camera used to take them. It is possible to work backwards from the relationships of neighboring pixel values in a shot to identify the model-specific demosaicing algorithm that combines red, green, and blue pixels on the sensor into color image pixels. Forensics teams are already licking their chops."

Comments

stretch?

[Speare]

As even the cellphones are producing 3 megapixel images now, very few people need to be passing full-resolution originals around. If you scale the image down to a screen-usable 1 megapixel image, there's not going to be a lot of bayer mosaicking information still available.

Re:stretch?

[narcberry]

Maybe so, but you still have the full size images on the camera. If someone were to get a hold of that they would be able to tell what camera took the images after a few weeks of intensive forensic study.

Re:stretch?

[shird]

Maybe so, but you still have the full size images on the camera. If someone were to get a hold of that they would be able to tell what camera took the images after a few weeks of intensive forensic study.

Troll? If they get a hold of the camera with the photos on it, they would already know what camera took the photos. Plus they would have all the meta data in the photos themselves. This technique is only useful when said exif meta-data is removed. Usually some post-processing is also performed at the same time if someone goes to the effort to remove this data.

Re:stretch?

[Anonymous Coward]

Joke------>
          You

Re:stretch?

[trum4n]

Feed your RAW images to photoshop, then hit NTSC color mode, then compress to jpeg. All their secret information is gone forever. Only idiots would let this work. and oh yea, those idiots didn't delete the Meta-Data anyway, cause they dont even know what it is.

Re:stretch?

[Anonymous Coward]

Yikes.

Re:stretch?

[AngryLlama]

Congratulations on reemphasizing the obviousness of that joke.

Re:stretch?

[Anonymous Coward]

I got trolled :( Nonetheless, you could argue that the originals would still be stored somewhere prior to post-processing. And if they got a hold of that as opposed to the camera itself this technique may still be useful. But in such a case, the meta-data would typically still be in-tact as well. And the place in which it is stored would be a fair indicator of the camera used.

Re:stretch?

[arashi no garou]

Congratulations on re-reemphasizing the obviousness of my redundancy. Or something.

I'm going back to bed. Carry on.

Re:stretch?

[arashi no garou]

It's called "mock surprise" mixed with a bit of sarcasm. Sorry it went over your head.

In your defense, it was a half-assed attempt on my part.

Re:stretch?

[Anonymous Coward]

That whooshing sound you hear is the joke flying over your head.

Re:stretch?

[lysergic.acid]

or you could just use a camera with a Foveon X3 sensor. there's no demosaicing involved since it employs 3 vertically stacked photodiodes (red, green, blue) at each pixel sensor to capture color information.

here is a diagram showing how a multijunction photosensor works. unlike bayer filter sensors, Foveon X3 sensors produce no color artifacts.

Re:stretch?

[hvm2hvm]

I think he/she continued the joke but honestly, on Slashdot you can never tell for sure. Maybe I'm joking.

Re:stretch?

[Tinik]

But then wouldn't the lack of demosaicing itself be the tell-tale sign that it was taken with a Foveon X3 sensor?

Re:stretch?

[cunniff]

Eric: Horatio, there does not look like there is any mosaicing information in this image.
Horatio: Eric, that means the image was taken with a camera with a Foveon X3 sensor.
Cally: Zeroing in on professional camera stores... I have an address
Horatio (menacingly): Eric, get on it.

Where's my CSI: Miami royalty check?

Re:stretch?

[MrNaz]

Half assed? You continued a joke without adding anything to it, and followed it up with a kinda sarcastic reply which reduces the chances that a reader would even recognize your joke.

That's not even a quarter-assed attempt. I'd put it somewhere in the neighborhood of 12.5% of an assed attempt.

Re:stretch?

[wvmarle]

Sure... but how many people are really doing that?

I get more and more complaints that e-mails bounce: my mail server has a 10 MB per-email limit, and that should be enough. But many people copy the image from the camera, and then directly attach it to the e-mail. So I get many 3-4 MB sized attachments!

It really seems most people just don't care or don't know about this.

Re:stretch?

[the_womble]

It does, but rather than narrowing it down to a particular model, it narrows it down to any digital SLR (and maybe other types) camera made by Sigma.

Add to that the fact that reducing the image size will probably get rid of the evidence, using a raw image and demosaicing on a PC will tell you what software was used instead of what camera was used, there are a lot of limitations.

On the other hand, most people do not know all this - then again, most people are unlikely to think of deleting the meta-data either.

Re:stretch?

[Chrisq]

I might fool them by taking a picture of my Olympus and loading onto my Sanyo though. Seriously if you carried a suspect image around on a different camera you could now call an expert witness to show that it was not taken on this camera - and since the only other people who had access to the camera were the police it must be a frame.

Re:stretch?

[moonbender]

It does, but rather than narrowing it down to a particular model, it narrows it down to any digital SLR (and maybe other types) camera made by Sigma.

Given how few Sigma cameras are sold compared to any popular model by the big manufacturers, that isn't say much, right? At the moment, anyway.

Re:stretch?

[XSpud]

Seriously if you carried a suspect image around on a different camera you could now call an expert witness to show that it was not taken on this camera - and since the only other people who had access to the camera were the police it must be a frame.

Commonly called a "picture frame" I believe.

Re:stretch?

[alexandre_ganso]

very few people need to be passing full-resolution originals around.

I wonder why all this noise. Cameras can be identified by exif info. I found that even after being reduced from 6 megapixels to the 500x350 image on fotolog.com, the image still retained the camera model, chassis number and lens number of my ex-wife's one...

Re:stretch?

[c0p0n]

8mpx in the case of a new sony ericsson handset, can't remember the model. 5mpx cameras on phones are fairly common these days.

Not that mpx matter anyway on cameraphones, they still use shit optics and sensors.

Re:stretch?

[Chrisq]

Commonly called a "picture frame" I believe.

Groan....

Re:stretch?

[ti1ion]

If you have the computer the image was stored on, you already have more information than what this article deals with. There is no point finding out what camera made the image if you can check for finger prints/DNA on the computer itself. And that is not even getting into searching all the files on the PC and tracing all activity. Also, how did the person in question get to that computer? Is the owner of the PC related, etc.

Re:stretch?

[Lumpy]

Cellphones are producing 3 megapixel images. but their quality is still far less than my 8 year old Kodak DC120 that shoots less than 1 megapixel.

Cellphone cameras will continue to suck until they make one with a decent lens.

Re:stretch?

[Lumpy]

"Foveon X3 sensors produce no color artifacts."

Incorrect. they can show color fringing like you get with a 3CCD HD video camera when shooting a high contrast sharp edge.

Granted you need to be in the right conditions to make it happen, but it certainly can happen.

Re:stretch?

[Anonymous Coward]

Ah, Slashdot, where the severely autistic come to get mocked by the high-functioning autistic.

Re:stretch?

[jeffmeden]

You forgot the obligatory

Horatio: It looks like this photographer captured... himself
[Horatio puts sunglasses on over existing sunglasses]
[music: Yeeeeeaaaaaaaaaaaahhhhhhh]

Re:stretch?

[Sax Maniac]

I want to take back all the mod points I've ever received, and put them all on this post. Well done.

Re:stretch?

[hierophanta]

^HILARIOUS! (too bad i got no mod points left)

Re:stretch?

[HannethCom]

Because of how the Foveon X3 sensor works, if you have the full sized unprocessed picture, you might not be able to tell the brand of the camera used, but each individual camera probably has a distinctive blur pattern in the red and blue ranges, so if the forensics had the camera they'd be able to identify that specific camera was the one that took the picture.

Re:stretch?

[Deefburger]

Having the images ON the camera is the proof! No Forensics nessesary.

Re:stretch?

[bytesmythe]

Reminds me of this comic...

CSI

What about multiple cameras using the same sensor?

[Chirs]

Quite often there are different manufacturers using the same sensor. Since this locks in the physical aspects of the sensor layout, I would expect the demosaicing algorithm to be basically identical across all these bodies.

Even after image manipulation?

[MR.Mic]

I wonder if this method still holds up after noise removal, or even something as simple as an image size reduction. Anyone more knowledgeable on the subject care to speak up?

Re:Even after image manipulation?

[morgan_greywolf]

I doubt it. I do a LOT of image processing, and I have to say that after color correction, noise removal, etc., I very much doubt that this technique would hold up.

Re:Even after image manipulation?

[JohnVanVliet]

just run the photo through" greycstoration "

greycstoration -restore ???.jpg -nu 3 -dt 30 -iter 3 -std 2 -o ??.png
convert ???.png ???.jpg

Re:Even after image manipulation?

[jools33]

There are photodesk editors with experience who claim to be able to identify the camera model, the lens used and the post processing software used to produce the jpeg / tif file. This is possible due to various characteristics that are introduced at each stage in the digital photographic process. Giveaways for the camera body used are the base resolution, any colour casts in the image, iso performance, dynamic range. For instance many Canon DSLRs are criticised for producing muddy greens in their images - especially at higher ISOs as the dynamic range is pushed to extremes. Then you can usually work out the lens - by the obvious field of view first, then the flaws in the shot - various lenses from various manufacturers have different flaws. For instance the 70-200 f/2.8 from Nikon has characteristic vignetting that can often be noticed even after post processing, then other cheaper lenses give various defects to the image such as chromatic aberation. The flaws in the image give away the body and lens. Also the sensor used gives certain image characteristics that are fairly easy to spot even to the keen amateur photogs eye - for instance telling the difference between a full frame sensor and a smaller APS sized sensor - the full frame image typically has a much smoother more film like attributes with less digital artifacts. Also the same can be said for post processing. This software usually leaves various characteristics - that remain with the image, and this varies for each different software vendor.

So this is all possible to a well trained human eye - don't see why it shouldn't be possible in software - but not sure of the real benefits of being able to identify this - as many photogs often leave the exif data - and that tells you everything.

Re:Even after image manipulation?

[BobearQSI]

I touch up and meticulously make print-ready most of my kidnap victim photos. The contrast has to be 'just right' to show their fear. There were a couple I didn't retouch, however, so I've let those kids go now.

Raw images?

[evanbd]

So, if I shoot in raw mode, and then postprocess in software to get a jpeg, the demosaicing signature should merely identify the software, right?

Of course, I wouldn't be surprised to learn that the distortion uniquely identifies the lens used...

Re:Raw images?

[complete loony]

And the jpeg encoder will be identifiable as well. (Can't think of the name of the software right now...)

Re:Raw images?

[Guspaz]

One could also potentially design an algorithm that subtly obfuscates the subpixel values in such a way that it defeats the technique while minimizing the apparent visual changes to the image.

In fact, since JPEG already downsamples the chroma channel, I'd imagine that merely applying JPEG compression would already defeat any attempts to do this...

Then again, this may all be moot; cameras produce images at increasingly insanely high megapixel counts. what people actually need is often far lower. So as others have pointed out, simply resizing the image (such as to prepare it for web display) may be sufficient.

Re:Raw images?

[Guspaz]

Problem is, you don't need to buy a JPEG codec, so there isn't necessarily anything to trace back to you.

I mean, what if the JPEG codec is determined to be the one included with MS Paint? How does it help to know that the person you're looking for used a copy of Windows XP or Vista?

Re:Raw images?

[Facegarden]

...Of course, I wouldn't be surprised to learn that the distortion uniquely identifies the lens used...

Nah, not likely. Unless you knew exactly what the scene was supposed to look like, from that exact angle and everything (and even then it would likely be impossible), you just can't know what is a distortion from the lens and what is part of the scene. Unless, like, the scene happened to be a highly accurate checkerboard pattern. Then you can look and see what lines aren't quite straight and get some distortion information, but that would be tough.

I know software can correct for lens distortion if it has a distortion profile for a certain lens (which is probably made by shooting a checkerboard type pattern...), but knowing to move every pixel to the left one is a lot easier than knowing if every pixel was moved to the left one by the lens, if that makes any sense.

Put another way, it's easy to put soda in your mouth and have yellow stuff come out of your underbits, but very difficult to do the reverse.
-Taylor

Re:Raw images?

[zippthorne]

I don't really see that as an issue. This seems like more of a "additional confirmation" tool that you'd use in the courtroom, rather than as a primary tool that you'd use to discover the identity of a person of interest.

Re:Raw images?

[Nikker]

As long as all the operations are carried out in scale you could likely determine the original 'finger print' since they would likely correspond. This could differ depending on the amount of alteration as well as distribution of the finger print across the pixels. Reducing the image to gray scale then using a separate function to interpret the color from there may be enough in some cases but YMMV.

Re:Raw images?

[Speare]

You really don't need anything so clean and nice as a full-scene checkerboard, to calculate a lot of lens details. Two or three moderate-length manmade straight lines that are at different angles should be enough. Like two edges of a table, a tall building, etc. That should be enough to give you the general curvature coefficients, which in turn would be pretty close to giving the right field of view. I don't think you'd be able to tell Sigma from Canon from Nikkor from Leica from Tokina from Zeiss glass.

Re:Raw images?

[Bob The Cowboy]

Put another way, it's easy to put soda in your mouth and have yellow stuff come out of your underbits, but very difficult to do the reverse.

I'm never drinking Mountain Dew again.

Re:Raw images?

[AliasMarlowe]

So, if I shoot in raw mode, and then postprocess in software to get a jpeg, the demosaicing signature should merely identify the software, right?

Yes, they're just fingering the in-camera raw conversion to jpeg. Using external conversion changes the game.

There are comparisons of demosaicing algorithms used on the same raw image at several places on the net, such as http://www.rawtherapee.com/RAW_Compare/. The software can make a huge difference, especially regarding moire and related artefacts. Most of the raw converters default to a much too aggressive approach for small scale features, in my opinion. As a result they often create chromatic moire in the JPEG, and accentuate the problem further by sharpening (to hide the softness of typical cheap lenses). This is clearly seen in the examples at the linked site.

Identical detectors on different cameras usually differ in the optical antialias filter used, which can affect their susceptibility to moire on sharpening. This may leave some residual information to allow the camera to be identified even with external conversion of the raw image. It would first be necessary to identify the demosaicing algorithm/software, so identifying the camera just from residual artefacts from the antialias filter would not be easy.

Of course, I wouldn't be surprised to learn that the distortion uniquely identifies the lens used...

Raw processing packages such as Bibble Pro also include a database of distortion characteristics for many lenses, including zoom lenses across their zoom range. Optionally, the image processing can compensate for the distortion for any recognized lens. Of course, the removal of distortion may leave a signature, which will perhaps allow both the lens and the software to be identified. This would not be a trivial task, of course, since "identical" lenses differ in their optical characteristics, and probably none exactly matches its nominal profile.

Re:Raw images?

[Facegarden]

Put another way, it's easy to put soda in your mouth and have yellow stuff come out of your underbits, but very difficult to do the reverse.

I'm never drinking Mountain Dew again.

And you're probably better off. I think Mountain Dew is the byproduct of people who never quite realized that you can't make soda from pee... Well, unless you're NASA I suppose...
-Taylor

Re:Raw images?

[director_mr]

Not necessarily. Each camera has specific ways to turn Raw images into processed jpegs. You will notice converters that turn RAW images into jpegs always have a list of cameras their converters work on. This is because RAW images are unique to each type of camera. So (although I'm not 100% sure about this) it may still be true even if you take RAW pictures. That being said, most people don't take RAW pictures in the first place, so this technique is probably still very useful. Even if it doesn't work with pictures processed from RAW images after being taken out of the camera.

Re:Raw images?

[leenks]

Your operations in photoshop are extremely unlikely to fully disturb the relationships between pixels and sensor noise, but maybe you are able to perfectly remove all noise and mosaicing artifacts.

Regardless, the paper is an interesting read, especially given that their team is primarily focussing on the creation of algorithms that are resistant to malicious tampering.

Re:Raw images?

[Mr Z]

I imagine every kidnapper demanding a ransom is going to fully and professionally post process the images they send in to the media. Somehow, I doubt it.

Of course, this whole technique feels like a solution looking for a problem anyway.

Re:Raw images?

[russotto]

The demosaicing software probably could identify the combination of software and sensor. The distortion might identify the lens, but if you use DxO Optics or some other distortion-correcting tool, you can camouflage that as well. Add some distortion back to really fool them.

However, if you really want to defeat techniques like this, take the picture with a Canon Digital Rebel and a kit lens, or a Nikon D40 and its kit lens. Sure, they'll be able to identify the camera and lens model, but there are so many of them that the information will have very limited use.

Re:Raw images?

[ChrisA90278]

"you just can't know what is a distortion from the lens and what is part of the scene. Unless, like, the scene happened to be a highly accurate checkerboard pattern."

It need not be a checker board. ANy straight lines will do. For example if the horizon is in the frame or (better) parts of buildings. Whaen I correct out geometric distortion I never use a lens profile. I only correct out what I see.

Re:Raw images?

[Facegarden]

"you just can't know what is a distortion from the lens and what is part of the scene. Unless, like, the scene happened to be a highly accurate checkerboard pattern."

It need not be a checker board. ANy straight lines will do. For example if the horizon is in the frame or (better) parts of buildings. Whaen I correct out geometric distortion I never use a lens profile. I only correct out what I see.

Hmm, interesting. I figured that something like a wood building wouldn't be straight enough, because after painting it is kind of lumpy, but i guess you're probably not looking for small distortions, but larger ones?
-Taylor

Re:Raw images?

[Blue Stone]

>How does it help to know that the person you're looking for used a copy of Windows XP or Vista?

If it's VISTA, it narrows the search?

Re:Raw images?

[not-my-real-name]

Put another way, it's easy to put soda in your mouth and have yellow stuff come out of your underbits, but very difficult to do the reverse.
-Taylor

Wait a minute. This sounds like the last story about new equipment for the space station.

Re:Raw images?

[Kanasta]

There's plenty software that corrects for lens distortion.
So I guess this may become illegal one day?

So What?

[Lord Apathy]

So what if they can identify the make and model of camera. I own a D70. There are 300 billion d70 out there. Good luck on tracking a picture to my camera.

Re:So What?

[canajin56]

They don't have to. All they have to do is say they used forensics just like on CSI, and it shows it was taken by the same kind of camera you own. Sure, you can say there are a lot of them out there so it proves nothing. But you know who else says that? The bad guys on CSI, and their smug, latte drinking lawyers. Always demanding warrants and to be released if they aren't being charged with anything! EVIL

Re:So What?

[Ethanol-fueled]

In other words, let 'em use what they want as long as the source is provided for the defense.

Re:So What?

[narcberry]

You say this like it's bad news for the bad guys. When really all this means is it's easier for them to pin your crimes on the closest scapegoat.

Re:So What?

[John Hasler]

> Good luck on tracking a picture to my camera.

That's not the purpose. Knowing the photo was taken with a D70 eliminates all the zillions of cameras out there that aren't D70s. It's like knowing that a bank robber is a 6' tall blue-eyed blond male.

Re:So What?

[xIcemanx]

So what if they can identify the make and model of camera. I own a D70. There are 300 billion d70 out there. Good luck on tracking a picture to my camera.

RTFA:

While many people own the same camera models, Pollitt believes that this technique can still be used forensically. He says that because digital cameras have a shelf life of only 18 months, this can help to narrow down when and where it was sold. Just because it won't immediately narrow it down to a single suspect with perfect accuracy doesn't mean it won't be helpful in investigations.

Re:So What?

[dattaway]

And you know that 1x1 pixel is all the evidence we need. You see, that pixel represents a single atom, which has bands of electrons, each with distinct spins, each of those with unique quantum signatures all the way up to other dimensions in other universes, all tied together with string theory back to the original untouched photograph.

You may sign the confession now or we will get a court order to further examine the evidence...

Re:So What?

[xIcemanx]

So what if they can identify the make and model of camera. I own a D70. There are 300 billion d70 out there. Good luck on tracking a picture to my camera.

RTFA:

While many people own the same camera models, Pollitt believes that this technique can still be used forensically. He says that because digital cameras have a shelf life of only 18 months, this can help to narrow down when and where it was sold.

Just because it won't immediately narrow it down to a single suspect with perfect accuracy doesn't mean it won't be helpful in investigations.

Re:So What?

[taustin]

Forensically, it's as useful as saying "this bullet came out of this model pistol." Not conclusive by itself, but one piece of a larger puzzle.

99% of criminal investigation is eliminating who didn't do it, and this can be useful for that.

Re:So What?

[cayenne8]

"It's like knowing that a bank robber is a 6' tall blue-eyed blond male."

A bank robber with THAT description really would stand out.

Hardly any of them look like that from what I see on TV.

Re:So What?

[fuzzyfuzzyfungus]

I hope the "there are 300 billion of them out there" defence works better for you than it did for certain owners of cheap, common watches.

Re:So What?

[Anonymous Coward]

The bad guys on CSI, and their smug, latte drinking lawyers. Always demanding warrants and to be released if they aren't being charged with anything! EVIL

The only EVIL on CSI shows is the way the motherfucking cops use extortion.

"You don't want to give up privileged information on this guy? Fine, we'll be back with a warrant. Of course, we may have to dismantle your office for a couple of weeks to do a thorough search. What does a couple of weeks mean to your business? You do understand, don't you, that when we seize (God, how those bastards love the word "seize") your computer, our clumsy techs might return it with some important files no longer readable? So sorry. ... Oh, yes, ma'am, that's the perp we were inquiring about. Thank you for your cooperation."

Re:So What?

[Fastolfe]

I suspect this would be more useful as a way to exclude cameras that wouldn't have likely taken the photograph. If you have 100 suspects, and can mostly exclude 95 of them on this basis, that's useful.

Re:So What?

[vux984]

So what if they can identify the make and model of camera. I own a D70. There are 300 billion d70 out there. Good luck on tracking a picture to my camera.

Its useful the same way knowing the car that raced away from the scene of the crime used a particular tire, with a particular wheelbase. Or that a bullet was fired from a particular make of gun.

Neither will positively identify anyone, but if you were already a 'person of interest' in a long list of people peripherally related to a case that detail might put you on a MUCH shorter list if it comes up that you have that model. Plus its useful when they are asking a judge for a warrant. Judges really like specificity with warrants... A "We want to search his home and car for a Canon Powershot X"; he blogged here about buying a Canon Powershot X, he was caught on this surveillance tape leaving the scene carrying an indistinct object, the dimensions and shape of which are consistent with a Powershot X, and we know the photos in question were taken with a Canon Powershot X"... that's got a lot more weight than... "We want to search this guy for a digital camera, because a witness said he owns a camera, and he was caught on tape holding an indistinct smallish object which could be a camera, oh... and the photos we're interested were taken with a camera."

A reasonable person would view the second as a complete fishing expedition, based on no evidence, practically everyone has a camera and he could have been holding anything on that tape. The first request is specific - the photos of interest were taken with that model, and there is reason to beleive the person HAS that particular model, and that he had it with him on the that tape. Sure it could be a coincidence, but a warrant for that particular camera if he has one to check it out, might not be unreasonable.

Its also not unlikely that they can pair photos to a particular camera if they have both on hand due to micro-scrathes and other unique lens defects... the same way they can pair laser pritners to printed output.

Re:So What?

[Anonymous Coward]

99% of criminal investigation is eliminating who didn't do it

Unfortunately 99% of prosecution is sweeping those bits under the rug so the prosecutor can pretend to be tough on crime and leech ever more from society at higher and higher positions.

Re:So What?

[Anonymous Coward]

And you know that 1x1 pixel is all the evidence we need.

"Chief! We only got a 1x1 pixel area of the jpeg of the criminal!" "Okay take it downstairs to Abby and McGeek to check it out".

[Wiggly Lines]

"Yeah Chiefy it was pretty easy. We zoomed in on the 1x1 pixel image and we got this picture of the criminal which was inside there. And we got the model of camera he used too, an Motorola RAZR Smartphone." "Yeah Chief, there's only been ninety jillion RAZR phones made, so we hashed the 1x1 pixel image and got the phone's SIM number out of it. It's him all right. Science never fails. We get the criminal every time, just like in real life." "Good work Abbs, have a cookie. And McGeek, get a haircut, you look like a hippy." "Thanks Chief". [Exeunt all, Abby munching cookie]

Re:So What?

[theheadlessrabbit]

i have a d70 too!

and i bought mine used, so even if they are able to trace it back to my exact camera, that doesn't prove that I was the one who shot the image.

how would this technology deal with used goods and re-sellers?

Re:So What?

[Anonymous Coward]

Looks like somebody tried contesting a speeding ticket and failed. ;)

Re:So What?

[rubah]

so that's where all the names on the No Fly List came from . . .

Re:So What?

[mysidia]

Yes... CSI is very realistic in that regard.

Standard police tactic in real life, i'm sure.

Use fear/insinuation to get whatever info needed.

Except IRL it's not merely extortion, insinuated threats like that are all real.

Re:So What?

[prockcore]

I'm just trying to imagine a crime where a photo was taken by the perp and then sent to the cops.. and the make of the camera matters more than the delivery system used for the photo itself.

Re:So What?

[ancient_kings]

"It's like knowing that a bank robber is a 6' tall blue-eyed blond male." Err...not in Finland...

Re:So What?

[Anonymous Coward]

The stuff you see on CSI and other similar crime shows is grossly unrealistic. It's actually so unrealistic that judges typically give a bit to jurors when they're in the panel that they should not put cops onto a standard compared against these shows (no one would ever get convicted). One of my judges used to put it something like this: "You need to understand the difference between reality and television. On these shows, the investigators find a footprint with blood, match it up to a boot tread, then find a butterfly wing elsewhere in the room, stick it into a computer, and 30 seconds later, they have conclusive proof beyond all doubt that the suspect did it. But in real life that will basically never happen. It is very likely that you may hear only testimonial evidence, and not see any photographs or any other physical evidence." And I cannot agree with him any more. I've NEVER even heard of an investigator going this deep to catch someone. Here's the problem -- your local police department probably has so many unsolved crimes, grossly insufficient funds, an extreme lack of sophistication, or a combination of the three. There's no way they can devote resources to do a forensic analysis to see what camera model took those digital pictures. In that same amount of time/resources, they can take 3 burglars and 10 crackheads off the streets. Meanwhile, if the government did try to present that evidence, the defense will bury the state in various motions (delaying the case), which is USUALLY a huge benefit to criminal defendants. Because the state usually has few resources to gather this CSI standard of evidence evidence, their cases are generally dependent on the testimony of victims/witnesses/cops, who often die/recant/move/retire/etc. Why would a state attorney want to risk losing testimony to gather forensic evidence that the jury won't understand and will probably be virtually irrelevant? I'm not saying that it's completely useless... but it'll probably happen MABYE once in the next 100 years.

- criminal defense attorney (not yours)

Re:So What?

[tftp]

To exclude someone you'd need to prove that the person never had access to a certain camera. This is tough, considering that cameras are bought and sold for cash, with no ID required.

Re:So What?

[penguinchris]

Just FYI, when they look at bullets in an investigation, they match it to the actual original gun, not to a specific model (other than bullet caliber.) They take the bullet from the victim's brains, fire a bullet from a gun of the same caliber seized from a suspect, and can see if they match.

Sorry if you already knew that, but from the wording of your post I wasn't sure. I think it's pretty cool so in case you didn't know, there you go. The things you learn from Dragnet.

Re:So What?

[penguinchris]

It's clearly a technique for child porn investigations. If you have a suspect who owns the same kind of camera you determined was used to take the photo in question, which the investigators most certainly didn't get from the photographer them self, you can know whether to search for more evidence or to eliminate them from your suspect list.

Most people who do this kind of thing are not necessarily going to realize this is possible, so aren't going to think of the obvious solution, which is to borrow someone else's camera or to own two cameras (one bought with cash) and hide the one used for dirty deeds really, really well (in a train station locker, say.)

So basically this is pretty weak evidence, and not that great of an investigative tool, in my opinion. Of course, zealous investigators are going to push stuff like this as fool-proof evidence, despite the multiple problems with this such as I just described in the previous paragraph.

Re:So What?

[KDR_11k]

With child porn investigations this probably counts as sufficient evidence to convict someone seeing how quickly people go rabid when the subject comes up.

Re:So What?

[KDR_11k]

That's only once they have found the gun. They can't take the bullet and instantly say "oh this is registration number XYZ-12345".

Re:So What?

[Eivind]

It's still useful in a negative sense.

Knowing the picture came from a certain model camera isn't very useful as proof that a certain person took it, afterall there are many cameras that are produced by the million.

But it is -quite- useful for narrowing the field. Someone who doesn't posess such a camera very likely did NOT take the picture, that's useful information.

It's like, knowing that a criminal was about 30 and male isn't useful as proof that a certain person did it. But it is -very- useful for eliminating from the list of suspects people who are 15, or 50 or female. It's easier to thoroughly investigate a short list than a long list.

Re:So What?

[clickety6]

'person of interest'

Wow, you guys are really PC on here!

Over here, we normally just call them suspects...

Re:So What?

[maxume]

To positively exclude someone, yes. To better focus your investigative resources, no.

Re:So What?

[Schroedi]

On a similar note, it should be possible to match a (DSLR) photo to a camera by looking at the dust distribution (for those who don't have a fancy ultrasonic cleaning system)

Re:So What?

[vux984]

Over here, we normally just call them suspects...

Its not PC; its a different list. 'Suspects' is a shorter list than 'person of interest'.

You can be a person of interest to a case without being a suspect. A suspect is someone who you think might have committed a crime, a person of interest includes suspects, but could also include people you think or even absolutely know didn't but you believe has information relevant to it, they might know a suspect, or work within sight of the crime scene, or sold the weapon used in the murder from their store and thus might recall who bought it, etc, etc...

Re:So What?

[kent_eh]

While many people own the same camera models, Pollitt believes that this technique can still be used forensically. He says that because digital cameras have a shelf life of only 18 months, this can help to narrow down when and where it was sold.

1) RE: Originally sold. My 7 year old carries a 4 Mpixel camera that we bought at a yard sale, which that guy bought off E-bay. "They" might be able to tell that the picture of interest was taken by a camera originally sold at a WalMart in upstate New York, not that it was taken by a kid in Winnipeg.

2) RE: "shelf life". Of the 25+ cameras that my extended family own, none are newer than 18 months. Most are 2-3 years old.

Re:So What?

[lwsimon]

It is generally not possible to determine the model of firearm a bullet was fired from. Notable exceptions include the MP5 and Marlin firearms with polygonal rifling.

In many cases, even with an intact bullet, its not possible to determine the cartridge it was fired from. For instance, the same bullet is used by .30 carbine, .308 Winchester, 7.62 NATO, and many other rifle rounds.

Re:So What?

[rantingkitten]

And if they have five suspects, and two of them have D70s while the other three have something else, they've narrowed their investigation.

Of course, a bright chap would rent/borrow/steal a camera to do whatever criminal underworld photography he was doing, instead of using one the cops are likely to find in his home or car, but whatever.

Re:So What?

[Explo]

Then again, many of us with older DSLRs that lack the dust removal functionality just clean up the sensor manually (typically by using a squeezable air pump made for that purpose, or by swiping them with something like the Copperhill kits) when we get sufficiently annoyed with dust spots on the images.

I suppose some of the more persistent dust spots that are small enough to not be an annoyance might be useful for that kind of purposes though, although it might not be very reliable anymore.

Re:So What?

[A440Hz]

"Zoom in on that pixel. OK, now enhance it."

Re:So What?

[vux984]

As for laser printers, they can be identified uniquely because, on each page, they surreptitiously print a binary code (serial number, at least) in very small, light yellow dots. Yellow on white paper is nearly imperceptible. Wiki it for the whole story, including how to find and interpret the dots.

Yes, but even without that, you can match a printout to the drum, based solely on defects due to wear in the printer. The printer/paper equivalent of ballistics matching a bullet to the barrel it was fired through.

http://portal.acm.org/citation.cfm?id=1411332

Re:So What?

[stewbacca]

It's clearly a technique for child porn investigations.

Maybe I'm naive, but it took this long into the discussion thread for somebody to explain why this is even a story. I hadn't thought of that (because I'm a decent human) and I guess everyone else *thought* it, but were a bit uncomfortable stating what is otherwise totally obvious to most folks.

Re:So What?

[stewbacca]

It would be easy to investigate and discover I bought my Canon Rebel Xsi on Amazon.com...whether you can get a warrant for that sort of thing or not is another story. So, if (big if) I was suspected of a child porn ring and they say the pics were taken with a Canon Rebel Xsi, that's a start, but hardly worth anything on its own merit. I think they'd have a better case finding actual child porn pictures on my personal computers or interrogating people in my porn ring. If it got to that point, pinning a specific camera model to my ownership is sort of overkill. In short, if I were committing this sort of crime, disguising my photographic finger print would be the last worry on my mind because it is neither going to convict me nor implicate me (on its own merit).

Re:So What?

[pimpimpim]

I thought I had seen everything, but this really is damned crazy. Probably the best sold watch in the world. It's like using the fact that someone is wearing levi's as a warrant for arrest.

Killjoy

[ciaohound]

Well, that kind of takes the fun out of this kind of story in which images from a Canon point-n-shoot are indistinguishable from those taken by a $40,000 Hasselblad.

Re:Killjoy

[Azarael]

That isn't the conclusion that the author came to. If you compare http://www.luminous-landscape.com/images-85/h2.jpg and http://www.luminous-landscape.com/images-85/g10-comp.jpg there is definitely a different between the yellows and the depth of focus on the expensive camera is far better (compare the red leaves on the upper left).

Re:Killjoy

[Colonel Korn]

That isn't the conclusion that the author came to. If you compare http://www.luminous-landscape.com/images-85/h2.jpg and http://www.luminous-landscape.com/images-85/g10-comp.jpg there is definitely a different between the yellows and the depth of focus on the expensive camera is far better (compare the red leaves on the upper left).

Depth of field isn't a question of better or worse, you know, it's just different. If you want to poke at that story, you might just point out that a the limited image size makes the comparison pointless. These days, cheap digital cameras make incredibly expensive pro cameras more useful for either flexibility or niche markets (like >13" prints). That doesn't mean professional cameras aren't worth it, just that they're not worth it for everything.

Re:Killjoy

[Azarael]

I don't disagree, the point that I was trying to get at was that the OP's conclusion didn't jive with the site. I've never owned an SLR and I'm pretty sure the majority of the photo quality problems I've had are the fault of the person holding the camera.

Re:Killjoy

[S-100]

You missed the point. He said that every sensor is different, so each needs to be adjusted as desired. Claiming one is "better" because of the yellows is a) not what he said and b) irrelevant to the discussion.

As for the depth of field, again you get it wrong. Depth of field is adjustable - one camera or image isn't better or worse if shot with a particular depth of field. What he said was that the Blad pictures were shot with a narrower depth of field and that his experts were able to discern which were which by looking at the depth of field of the image.

Re:Killjoy

[johnlcallaway]

My wife and I have two point and shoot cameras, a Nikon and an Olympus. We also have a Pentax dSLR.

Looking at the images at 100% scale and you can see a tremendous difference in the amount of noise in the backgrounds. That is mostly caused by the smaller size of the CCDs and the quality of the sensor itself. Plus, the higher end cameras have far better noise reduction software built in.

Depth of field is EVERYTHING to taking pictures. By using a long lens and a large aperture, bars around zoo cages disappear, the annoying crowd behind the bride also disappears, or that person just standing behind your subject gets just the faintest blur so your eye is drawn to the subject. Or use a small aperture and everything is brought into crisp focus.

Then there is being able to use higher quality optics. I recently used the Pentax camera to take some campfire scenes using a 50mm(film) lens set at 1.4f. I was able to take clear, handheld images around the campfire. Try that with a point and shoot.

I'm not knock the PS cameras. I use them when I'm riding my motorcycle to get action shots of those I ride with. That would be impossible with a dSLR or SLR camera, they are just too big and bulky.

But if someone wants to take high quality snapshots to share, nothing beats a dSLR. Pricey, yes. But well worth it for the serious photographer, be they professional or hobbyist.

Re:Killjoy

[swillden]

Looking at the images at 100% scale and you can see a tremendous difference in the amount of noise in the backgrounds. That is mostly caused by the smaller size of the CCDs and the quality of the sensor itself. Plus, the higher end cameras have far better noise reduction software built in.

In addition to noise, the small digitals show lots of other image degradation as compared to a dSLR. They lack sharpness and have issues with distortion, color accuracy and chromatic aberration. The ultimate source of all of those issues is the glass. You simply can't get the same level of quality out of a half-inch lens as out of series of two-inch lenses (assuming similar technology applied to both).

I just shake my head at the ever-increasing megapixel numbers on compact digital cameras. I know they're great for marketing, but for the camera owners they do nothing but produce bigger files, with no better image quality than if they'd had a smaller pixel count. Once you get beyond the resolution of the glass, there's just no point in adding more pixels.

I just read the Haselblad/Canon comparison, though, and I have to point out that the Canon G10 is not what most people think of when you say "cheap digital". It's not an SLR, but it's close, with larger, better glass than most P&S cameras and a larger sensor. 15MP is a bit much for those lenses and that sensor size, but it's not that crazy.

Re:Killjoy

[inviolet]

As for the depth of field, again you get it wrong. Depth of field is adjustable - one camera or image isn't better or worse if shot with a particular depth of field. What he said was that the Blad pictures were shot with a narrower depth of field and that his experts were able to discern which were which by looking at the depth of field of the image.

Smaller depth of field requires a larger aperture. The tiny aperture of a P&S camera cannot get large enough to yield a narrow depth of field. For those rare occasions when depth of field is important for picture composition, a P&S camera will not do no matter how many pixels it has.

(Yes I've owned SLRs, but now I own only P&S cameras.)

That said, I think the superior image quality from expensive cameras is mainly the product of cognitive dissonance. :)

Re:Killjoy

[stewbacca]

I'm a relative new-comer to digital photography (did lots of 35mm film in the 80s though) and I was able to spot the point-n-shoot image immediately (in the link you provided). I'm not saying it's $40,000 less nice of an image, but it definitely isn't "indistinguishable". Sounds like somebody just wants to gripe about a $40,000 camera costing $40,000.

Re:Killjoy

[stewbacca]

Depth of field isn't a question of better or worse, you know, it's just different.

It most certainly is! If you want a shallow depth-of-field, but your cheap lens isn't capable of producing it, then that is a case of DOF being better or worse.

Re:Killjoy

[stewbacca]

My father was a serious hobbyist photographer in the 70s and 80s (his father was a professional photographer) and even HE fell for the megapixels marketing mumbo-jumbo and bought a cruddy Sony dSLR based on the megapixel rating. It's an easy way to part otherwise well-meaning consumers from their cash.

Re:Killjoy

[ciaohound]

Sounds like somebody just wants to gripe about a $40,000 camera costing $40,000.

No, the writer still sees a place for large format and SLR cameras, especially for very big enlargements. But the point-and-shoots keep getting better and better, and while I'm no pro, I know of pros (David Hobby, Darwin Wiggett) who have reached the conclusion that they can do the job for many professional applications, and they're a lot easier to carry around. In a few years, today's digital SLR may look very clunky and dorky hanging around one's neck.

Re:What about multiple cameras using the same sens

[fugu]

After the sensor takes the RAW data, the camera processes the image (some noise reduction, curves, and compression) to get a jpg. Since this conversion would vary between manufacturers (or even RAW software) I'd imagine that the process would leave behind similar "fingerprints."

90% accuracy...and filters

[syousef]

You can do all sorts of stuff to an image that would shot holes in this technique. Resize (shrink, or grow and reinterpolate), apply a filter (curves, b&w or sepia would be easiest but there are others). Hell put it through an artistic filter. Still at 90% accuracy, in most cases, I wouldn't even bother!

Re:90% accuracy...and filters

[narcberry]

I add comments to all by pictures. This makes it more difficult as well. But I'll admit it's annoying to have "Happy Birthday!!!" on each and every photo.

Really...

[Mozk]

All the more reason to use film.

Re:Really...

[afidel]

Film can be identified down to the batch, MUCH more unique than a highly quality controlled part like a CMOS sensor.

Meta data?

[Ian Lamont]

Is the make and model data already included in jpeg's file header? See here

Re:Meta data?

[theNetImp]

I was going to say all my cameras have the make model and serial number built right into exif data of every photo I take.

Re:Meta data?

[afidel]

Yes, it's called EXIF and they are talking about a photo with the EXIF stripped.

Re:Meta data?

[Diddlbiker]

Of course someone who is stripping the exif data will never resize the image and run some sharpening over the image just to cover their traces, right? Which would be st00pid because now they know you are (and I quote): "He says that because digital cameras have a shelf life of only 18 months, this can help to narrow down when and where it was sold." "Yep, this one was taken by a Canon Powershot A510 of which only 5.7 million were sold. We also know that this particular model was either sold in North America, Japan, Europe, Africa, Australia, South East Asia and South America. That should narrow it down."

Re:Meta data?

[John Hasler]

> Of course someone who is stripping the exif data will never resize the image and run
> some sharpening over the image just to cover their traces, right?

Some will, some won't. Criminals are notoriously careless and stupid.

> Yep, this one was taken by a Canon Powershot A510 of which only 5.7 million were sold.
> We also know that this particular model was either sold in North America, Japan, Europe,
> Africa, Australia, South East Asia and South America. That should narrow it down.

Yes. Of the 18 initial suspects only two own that camera. Concentrate your investigation on them.

Re:Meta data?

[PietjeJantje]

Woohooo. Smart criminals must love digital evidence. What is a tool for investigators to catch stupid criminals, is also a tool for the smart ones to use the investigators to their advantage. So I kill my mother in law in one strike using my Model M. Then I take some pictures of the corpse using a Canon Powershot A510 which I'm not tied to (it's purely coincidence that my brother in law also owns one), post some pictures on smackmymil.com, and dispose of it. In fact, I own a Nikon D300 and have fanatically been taking pictures of my cat.

There is something inherently wrong with digital, producable evidence. In my example I was on the "right" side of the equation... could be worse.

Re:Meta data?

[suggsjc]

Yes, it's called EXIF and they are talking about a photo with the EXIF stripped.

Don't say things like that, else they'll consider any photo without EXIF to be taken by a terrorist.

Re:Meta data?

[zarkzervo]

> Of course someone who is stripping the exif data will never resize the image and run > some sharpening over the image just to cover their traces, right?

Some will, some won't. Criminals are notoriously careless and stupid.

If you are careless and stupid, how did you remove the EXIF-data? It's difficult enough to find a good EXIF-editor alerady. And if you actually go through all the labour of removing the EXIF-data, you probably would also go through the steps of altering the image. Unless, of course, you are a photo freak and really, really have to use the raw format to capture all the details of your crime.

> Yep, this one was taken by a Canon Powershot A510 of which only 5.7 million were sold. > We also know that this particular model was either sold in North America, Japan, Europe, > Africa, Australia, South East Asia and South America. That should narrow it down.

Yes. Of the 18 initial suspects only two own that camera. Concentrate your investigation on them.

Here, I must agree.

For what purpose?

[actionbastard]

"Forensics teams are already licking their chops."

I can only see this, in a positive light, as uncovering fraud or deception -possibly even supporting a claim as to the veracity of a witnesses' testimony to photographing a crime- instead of this being used in a nefarious way. Although, once the algorithm is well understood, certain 'non-well-intentioned' organizations or individuals will use this for evil instead of good. But in the meantime, how would this worry the average digital shutterbug?

Re:For what purpose?

[Free the Cowards]

Could perhaps be used for prosecuting people who take photographs in "forbidden" areas, such as evil people who dare to take pictures in the DC Amtrak station, on the Pentagon reservation, and other such areas. I can't quite figure out how this would play into it though.... And of course as far as I know nobody has (yet!) been prosecuted after the fact for such photographs.

Re:For what purpose?

[davolfman]

Sounds a lot like tracing typewriters to me.

Re:For what purpose?

[carlzum]

Except with typewriters and gun barrels there are physical nuances that leave unique markings on bullets/letters. This just identifies the model, and even that's degraded as the image goes through various software manipulations, as other posters pointed out. It may help reduce the population of digital camera owners in question, but it doesn't seem like the kind of evidence forensics teams are "licking their chops" over.

They're after you

[tsa]

I have a friend who is so paranoia about leaving personal data on the Internet he doesn't even use his own name as login name on his iMac. Don't let him hear this or I will never get any pictures from him by mail anymore!

Re:They're after you

[nedlohs]

You'll have to tell us who he is so we can be sure not to let him hear.

Re:They're after you

[tsa]

I guess you're right :)

The funny thing is: he buys a lot of stuff at the Dutch version of eBay. I wonder how he does that.

Re:What about multiple cameras using the same sens

[qwertphobia]

You insensitive clod! I shoot my digitals in the raw!

Oh my!

[winkydink]

I better sell my Nikon D300. They'll be able to trace it back to me. Or one of the other gazillion people who also bought one. Hmm... on second thought...

Re:Oh my!

[daybot]

I better sell my Nikon D300.

Showoff!

Re:Oh my!

[winkydink]

No. Talking about my glass is showing off. :)

Re:Oh my!

[philspear]

I know what you mean! The thought of the government being able to tell what digital camera I used to take a picture of myself for my facebook profile is terrifying.

Re:Oh my!

[AgBullet]

I better sell my Nikon D300. They'll be able to trace it back to me. Or one of the other gazillion people who also bought one. Hmm... on second thought...

you're missing the point. there usually are other factors in play in any investigation. having only the camera make to go by is useless, but not so if you've managed to narrow - through other criteria - your suspect list down to 10.

Re:Oh my!

[networkBoy]

so,
note to self:
for ransom photos buy a low-end point and shoot, pay cash, toss it in the fire/ocean/whatever when done.
-nB

Re:Oh my!

[severoon]

Actually, it's quite likely that a good forensic team could trace an image back to your individual camera. Every sensor has faulty photosites, and the in-camera processing algorithm automatically detects these and averages the values for neighboring photosites over them so they don't show up as a black or hot pixel in your images. The result of this is that your sensor will leave a fingerprint, much like a gun barrel leaves its individual signature on a bullet.

Up until now there was no way to make use of this sensor fingerprint that worked regardless of the post-processing done on the image, though, because the differences between types of sensors and manufacturer algorithms obscured which pixels were compensated for in the image. Now that this is apparently a separable part of the problem, however, I have no doubt that forensics ought to be able to trace images to an individual camera. (Like a gun, they'd need access to reference images from the same camera, though. I expect these are much easier to come by than reference bullets from a gun, however...most people have at least a couple of images they've made posted online for anyone that cares to look.)

Re:Oh my!

[ceoyoyo]

Or you could shoot RAW and then the camera doesn't do any demosaicing at all.

No Shit..

[retech]

That data is obviously on any uploaded pic site. The only way around is a copy paste of that image into a new file.

I just do not understand why it took a crack team of scientists to overstate the obvious... again.

Re:No Shit..

[afidel]

Um, stripping and faking EXIF are trivial anyone with a hex editor and a little knowledge can do it. In fact when a new camera comes out it's fairly common to fake the EXIF of a previous model to use the RAW converters before a model specific one comes out. Oh and the scientists were talking about identifying a photo with the EXIF data stripped.

Re:No Shit..

[nmg196]

RTFA! (or even the summary)

This story is about pictures with the EXIF meta data REMOVED. If you read the article, you'll see that copying and pasting the image into a new file does NOT solve the problem.

Re:No Shit..

[maxume]

Hex editor? Really? Why use a hammer when you can use a buzz saw:

http://www.sno.phy.queensu.ca/~phil/exiftool/

Spoofing Software

[John Hasler]

So when is the first software designed to process photos taken with one model of camera so that they appear to have been taken by another going be available on the Net?

Re:Spoofing Software

[NovaHorizon]

no, the real question is this. How long until we have to find cracks to disable software 'features' that hijack your picture viewing program so that pictures taken by certain cameras look horrid?

Re:In other news...

[sjs132]

Closer examination of my car revealed the tires leave marks on the ground if it soft enough or if I come to a sudden stop or extreme speed. This could give away the type of car you own to anyone. News at 11.

Still to come tonight:

Other tell-tales signs still not exstinquished in commen life are:

Your gate may give away your gender.
your address may give away your residence.
Your phone may give away your location.
Your CD's may fingerprint your burner.
Your IP Address may give away your computer location.
Your fingerprint may give away your identity.
Your paper trail ballot may give away your vote.
your googles may give away your fetishes.
your government may give away your tax dollars.

All these breaking news items will be revealed... Sometime soon, I can't say when, as that would give away my work schedule.

From the News for Paranoids, Good Day.

al;ksdjfl;aksdj.... .... .... ....

Umm.. you mean he wasn't on the net, he phoned this in?
Your serious?
Good God, Man! How will we track him now?
A Trace... Hmmm... eficient, but time consuming. I don't have time to wait for a judge.
Lets just wait until he includes an expose of us with a picture.
Yes, then we can back track the res. and multiplex it by the doohicky and figure out what camera he used.
 
YES! THE CAMERA! Then we'll call up the manufactures, find out where they are sold, narrow down the distribution points to the timezone that he calls in. From there we can cross reference with the memory stick size and figuer out what walmart he bought the camera from. Then it is just a matter of going through a few receipts to find a non credit card transaction for the camera, because he doesn't want traced - so it should be obvious. Now we have it narrowed down to the store, and we can watch a few minutes of security foottage to find him and view him going to the vehicle. Unless he gets on a bike, you still need a license plate and THEN WE WILL HAVE HIM!!!!! .... ....
What.
Damn... Round up the boys, were looking for a scanner!
And I want the Tin-Foil Sales figure results for a TEN-Mile-RADIUS in Five!

---- Tune in next week when our mark decides to buy Tin-Foil, with exact change at the self-checkout! ----

Re:What about multiple cameras using the same sens

[sjs132]

Ahh... That must of been you I saw at the park!

Good Gawd man, the poor lady didn't know what to think, haveing a bald, fat, nude man run up and take her holiday snap like that!

You left so sudden, she didn't get your number. For the picture, I believe.

Cherios....

This just in...

[fireman sam]

Cops didn't realize that most pictures posted on the interweb thing are usually post processed.

Re:This just in...

[m50d]

They're not, really. Sure, anyone doing serious photography will, but Joe's holiday snaps will probably just have been dumped straight on the web from the camera. And who do you think is more common?

Re:This just in...

[1u3hr]

And Joe's holiday snaps will have his name, address, phone number attached. No chop-licking forensics team required to find out who took it.

Re:This just in...

[Inda]

I think Joe gives up when he can't upload his 8mb pictures, from his brand spanking new 12mp camera, instantly. I know my Joe did.

What about standard designs?

[EmbeddedJanitor]

People like Ericsson Mobile Platforms (http://en.wikipedia.org/wiki/Ericsson_Mobile_Platforms) provide the same design to multiple handset vendors. As the industry progresses we can expect to see growing commonality.

Re:In other news...

[qzulla]

Very good, Mr. Bond, very good.

But what about that island he purchased? What about that? Surely it should have been on the list.

qz

the downside

[NovaHorizon]

(blatant CSI plug)

"Sarah! we found out that our image was taken by a Kodak easyshare C913."
"Good job Nick, how many suspects does that give us?"
"In Las Vegas? 50,000"

Re:the downside

[NovaHorizon]

yes it was. Now tell me why the police know what model camera you own to begin with without a search warrant and we're all set.

Add noise...

[spurioustruth]

How about just adding a steg file to all images consisting of 'n' kilobytes of random data before you post stuff to the interwebs. That should mess up any such analysis, right?

This has abuse potential

[KudyardRipling]

This sounds like the equivalent of "registering" typewriters with the government in nations once behind the Iron Curtain. It is no different than obtaining ballistic signatures from firearms at the manufacturer level. Yet one more reason to distrust governments.

Re:This has abuse potential

[smoker2]

How is a ballistic signature taken by the manufacturer bad ? Were you hoping to get a 100% virgin gun for your next kill ? I can't see any issue with that at all. The only time the authorities would need to get a match on the ballistics is if they found a bullet in a person or nearby after a malicious shooting. They aren't going to be collecting ballistics from bullets found at the range just for something to do.
Cameras and typewriters are used for innocent activities most of the time. The only time they are investigated is in forensics where they have been used in a crime. A bullet is only usually tested for ballistics after someone has died from its impact. If you didn't shoot the gun, why are you worried ?
And that is not the "if you have nothing to hide" argument. A gun is used to kill. That is its designed purpose. If you don't shoot at a person, you have nothing to fear. I don't care if you have a "right" to bear arms. You don't have a right to be completely anonymous when you kill someone, especially in a country that has shooting as a large fraction of its violent death statistics.

Re:This has abuse potential

[KudyardRipling]

Cameras and typewriters are used for innocent activities most of the time. The only time they are investigated is in forensics where they have been used in a crime. A bullet is only usually tested for ballistics after someone has died from its impact. If you didn't shoot the gun, why are you worried ?

Distrust of government is what separates us and this is where we must agree to disagree. Good fences, in this case 5000km of saltwater, makes good neighbors.

(OT) Almost accurate.

[Kadin2048]

They always seem to forget that the "come back with a warrant and tear your house apart" SOP also includes shooting your dog as a matter of course.

This should really help

[hyades1]

Luckily for anarchists, alleged terrorists and people who take pictures of cops thugging out on citizens, today's basic digital camera costs nearly as much as dinner for two at the local fast food joint. "Disposability" is your friend.

Re:This should really help

[John Hasler]

It's also the cop's friend. They frequently find evidence that has been "disposed" of. Yes, I know that _you_ would do it right, but...

Re:This should really help

[hyades1]

I keep a plasma arc in the basement expressly for the purpose. And a Golden Lab. She'll eat anything.

Rethink

[techdojo]

At first blush this struck me as similar to the printers that revealed a specific device by a faint set of dots printed on each piece of paper. On further thought, it occurs to me that the difference would be that the dot-tracking was shady where-as this is a triumph of statistical observation. The former being slimy and the latter sheer brilliance.

_________________________
http://techdojo.org/

Extra points for creative use of 'shorn'

[terbo]

I had no idea of what that word meant.
On topic, I doubt any of this information
would be available after a few passes
through some image magick utilities.

How should this work with RAW-Images?

[Moldiver]

How should this work with RAW-Images? I mean all my Images taken are converted by the same sw: Adobe Lightroom - So how should demosaicing be different between the cams?

the other way around

[kwikrick]

Its only matter of time before someone thinks up a way to manipulate an image such that it appears to be made with some camera and lens, and then this technology may be used to frame (haha) innocent people.

As trum4n wrote, this will not survive

[Jane Q. Public]

even the most trivial manipulations with Photoshop, Aperture, Corel, Gimp, or a great many other photo-manipulation tools.

Hell, even Windows Paint can mess this up.

Just discovered?

[Jason1729]

I read about this in Scientific American several months ago.

Re:In other news...

[computational super]

Good God, man -- you mean you can get that detail just by knowing whether the fence at the end of my walkway has a wooden vs. a wrought iron gate? Perhaps you mean my sex? Gender is a grammatical attribute. Sex is a physical attribute.

Don't worry, your post has given away your sex.

Re:What about multiple cameras using the same sens

[M-RES]

I shoot mine out a canon into the heart of the sun!

I'm Amazed

[Nom du Keyboard]

I'm amazed that there are that many different ways to process CCD image data. Certainly given the large number of different sensors on the market one can immediately winnow down the possibilities to only a few models to consider (assuming full resolution shots and high quality settings) so the problem isn't that big.

And given the variation pattern of defective pixels (both dark and hot) one could certainly match an individual camera if they had it to inspect in the same way ballistics can match a bullet to a gun. So this would likely be telling you which gun manufacturer and model to be checking, which you might not have known before.

Or is this one of those things that only works under "ideal conditions"?

Usefull application

[hierophanta]

i think the article is missing the point - this technology opens the door to a great comparison of camera and sensor technology.

with this tech someone could do an extensive research project on camera qualities.

Think of the DOF!!!

[stewbacca]

I get enough grief with my (mostly) bad photography on Flickr--now the authorities are on to me as well. If they figure out I shot f4.0, 1/60, at 44mm instead of f5.6 I'm totally screwed! I mean, just think of the depth-of-field!

Re:stretch? Fish in a Barrel

[Nom du Keyboard]

or you could just use a camera with a Foveon X3 sensor [wikipedia.org]. there's no demosaicing involved since it employs 3 vertically stacked photodiodes (red, green, blue) at each pixel sensor to capture color information.

Since almost nobody uses this once promising sensor technology guessing which camera might have produced the image is selecting from a very small results set.

shoot raw

[glyph42]

Just shoot raw and process the photos in Photoshop. Then their demosaic algorithm detector will just read "Adobe did it".

HOLY SHIT!!!!

[fataugie]

They figured out how to read the EXIM data stream.

BRILLIANT!

Re:HOLY SHIT!!!!

[soliptic]

1. It's EXIF, not EXIM.

2. 11th-14th words of the summary, never mind the article, "shorn of any metadata".

Truly, your comment was BRILLIANT. Brilliantly retarded.

Re:HOLY SHIT!!!!

[fataugie]

1. I noticed that immediatly and reposted below since editing isn't allowed.

2. This is slashdot...come on now...RTFA?

And finally, a hearty fuck you to you.

the NSA elephant in the room

[gregconquest]

All this talk of just using Photoshop to alter the images is just wrong-headed.

Photoshop's code is closed. Adobe, as well as every other closed-source image editor, could have long ago been "contacted" by agents from the NSA et al. and been "persuaded" under terms of an NDA to include watermark analogs in all images passing through their apps.

This happened with printer manufacturers; why would anyone assume it hasn't happened with image editors (and video and music everything else)? http://w2.eff.org/Privacy/printers/docucolor/

The cameras themselves may even have such tagging info included. Just 1% of the pixels shifted in a predetermined matrix (and compensated for in neighboring pixels) could easily and practically invisibly contain make, model, serial number, and date of file creation.

If this info is in thew hardware, even using open-source editors wouldn't ensure ID-free files.

What is needed, for images, would be an open-source photo ID stripper. This would be an app that: 1) removes all EXIF data from jpegs. 2) reconstitutes the photo by rendering, then applying an algorithm that slightly changes nearly every pixel (including slightly altering progressively larger sections of the photo in case specific pixels don't hold the data but areas do), and then re-compressing the image.

It could even be trained on specific cameras to remove hot and cold pixels.

This would be true anonymity.

More information

[Jedii]

Actually, this group has done more work in digital forensics including image manipulation detection, camera-model identification and unique SLR camera identification. Anyone who is interested to learn more about their wrk can visit http://isis.poly.edu/projects/forensics and find all the articles published under this subject!