Digital Camera signature
oxy
I am wondering if a particular digital camera always "imprints its
own unique signature" on photographs its takes.
Since some of the pixels are dead/not performing properly in every
sensor (perhaps this is not correct!) the pictures taken with the
camera will always have the same bad pixels showing up, sort of like a
bullet out of a gun.
Any thoughts,
Thanks
steve
photograph using some kind of 'image fingerprinting' methodology,
although I have not heard of any cases of this as of yet -- however it
can only be a matter of time before someone tries to claim the ability
to do so.
(I could think of some situations -- i.e. kiddy porn -- where being able
to match up a particular camera with a particular photograph would be of
great interest to law enforcement personnel. Also, being able to
positively prove proof of ownership of a particular photograph might be
of great interest to legitimate professional photographers in the
digital age. It remains to be seen if any particular technique utilized
to 'fingerprint' a particular camera will stand up to independent review
and scrutiny.)
Of course, my 10D adds the camera body serial number in the exif
information for each shot taken, although exif information would appear
to be easily removed from image files.
Given the degree of image processing done 'in camera' before image files
are stored to media it might be possible that a unique identifier could
be added to the image file using some kind of stenography technique.
A well thought out technique might allow the unique identifier to be
easily read if one knew how to appropriately process the image, but
extremely difficult to find otherwise. Of course, once the 'cat was out
of the bag', I would expect to see software tools available to remove
any stenographic unique identifiers surreptitiously added to digital
photographs in-camera.
steve
Povl H. Pedersen
> (I could think of some situations -- i.e. kiddy porn -- where being able
> to match up a particular camera with a particular photograph would be of
> great interest to law enforcement personnel. Also, being able to
> positively prove proof of ownership of a particular photograph might be
> of great interest to legitimate professional photographers in the
> digital age. It remains to be seen if any particular technique utilized
> to 'fingerprint' a particular camera will stand up to independent review
> and scrutiny.)
Even after post-processing, the dead pixels will often have had
influence on the picture (local slight colorcast/off-color pixels/
local blurriness), so fingerprinting should be possible as no 2
sensors are the same.
Juan R. Pollo
news:%zqJb.641$lE.5...@news3.news.adelphia.net...
> (I could think of some situations -- i.e. kiddy porn -- where being able
> to match up a particular camera with a particular photograph would be of
> great interest to law enforcement personnel. Also, being able to
> positively prove proof of ownership of a particular photograph might be
> of great interest to legitimate professional photographers in the
> digital age. It remains to be seen if any particular technique utilized
> to 'fingerprint' a particular camera will stand up to independent review
> and scrutiny.)
>
Hmmm...sounds like the reasoning anti-gun people use. "It's the CAMERA, not
the photographer"
Don't forget that the camera, like a gun, is only a tool. Just because a
picture was taken with your camera does not mean you took it. And if you
took a picture with my camera, do I own the rights? If Martin Scorsese shot
a movie with my camera, do I own it?
Juan
steve
Please keep in mind that I am not in favor of adding a 'unique id' to
photos in-camera. I would believe that this is an invasion of privacy if
it is done 'on the sly' without the knowledge of the photographer.
In fact, I would probably refuse to purchase any camera that did this
and did not allow the photographer to turn off the 'feature'
My post was meant as a discussion of the possibilities and not a
statement of support for the idea, even if it might assist law
enforcement in some unique circumstances.
steve
Juan R. Pollo
"steve" <doesno...@bitbucket.invalid> wrote in message
> All valid points.
>
> Please keep in mind that I am not in favor of adding a 'unique id' to
> photos in-camera. I would believe that this is an invasion of privacy if
> it is done 'on the sly' without the knowledge of the photographer.
>
> In fact, I would probably refuse to purchase any camera that did this
> and did not allow the photographer to turn off the 'feature'
>
> My post was meant as a discussion of the possibilities and not a
> statement of support for the idea, even if it might assist law
> enforcement in some unique circumstances.
>
Actually, I don't have a problem with a "unique ID" to cameras or other
property. I think it would reduce thefts and increase recoveries of stolen
property.
My point addressed the mentality that just because something was done with
an object, the object's owner must be responsible for the action.
Juan