Digital Noise Links Image to Camera

Discussion in 'Digital Photography' started by fishfry, May 7, 2006.

  1. fishfry

    fishfry Guest

    fishfry, May 7, 2006
    #1
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  2. fishfry

    Rich Guest

    hey thats good. Now when some pornographer
    uses a Rebel XT to take pictures, they'll have only
    about 5 million suspects instead of 7 million!!!!
    Rich, May 7, 2006
    #2
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  3. fishfry

    RW+/- Guest

    On 6 May 2006 19:47:12 -0700, Rich wrote:

    > hey thats good. Now when some pornographer
    > uses a Rebel XT to take pictures, they'll have only
    > about 5 million suspects instead of 7 million!!!!


    LOL, good one Rich.
    RW+/-, May 7, 2006
    #3
  4. fishfry

    Mxsmanic Guest

    fishfry writes:

    > Interesting! They can use the noise in an image to id the exact camera
    > the image came from.
    >
    > http://dsc.discovery.com/news/briefs/20060501/digitalnoise_tec.html


    No surprise here. It's roughly the same as identifying a gun by the
    marks it makes on a bullet, and of comparable utility and reliability.

    --
    Transpose mxsmanic and gmail to reach me by e-mail.
    Mxsmanic, May 7, 2006
    #4
  5. fishfry

    Bryan Olson Guest

    fishfry wrote:
    > Interesting! They can use the noise in an image to id the
    > exact camera the image came from.
    >
    > http://dsc.discovery.com/news/briefs/20060501/digitalnoise_tec.html


    I've heard of similar research, and I always think about
    working the other side to beat these techniques. If they
    can profile my camera, so can I. If there's a consistent
    patter, I ought to be able to correct for it. Then if I
    have access to a bunch of photos from some other camera,
    I ought to be able to develop a profile and add that
    camera's noise pattern in.

    How odd: the review sample lent to bobs-digital-cameras.com
    also photographed all this porn.


    --
    --Bryan
    Bryan Olson, May 7, 2006
    #5
  6. fishfry

    Marvin Guest

    fishfry wrote:
    > Interesting! They can use the noise in an image to id the exact camera
    > the image came from.
    >
    >
    > http://dsc.discovery.com/news/briefs/20060501/digitalnoise_tec.html


    My remarks apply only to the news item. I haven't read the
    eoriginal publication.

    By technical definition, noise is random. Therefore, noise
    in a camera does not repeat from photo to photo. There are
    irregularities in the sensor response that, in a good
    camera, are mapped and corrected by software. Some
    irregularities may not be corrected so well that they don't
    affect the image. I'd be surprised if, except in exceptional
    cases, the residual irregularites can be separated from the
    image and the true noise.
    Marvin, May 7, 2006
    #6
  7. fishfry

    Mxsmanic Guest

    Marvin writes:

    > By technical definition, noise is random. Therefore, noise
    > in a camera does not repeat from photo to photo.


    Noise can be consistent from one photo to the next when it is due to
    random, permanent defects in the sensor or in other parts of the
    camera (usually the sensor, though).

    > There are irregularities in the sensor response that, in a good
    > camera, are mapped and corrected by software.


    They cannot be corrected, they can only be masked. Masking them won't
    prevent them from being used for identification.

    > Some irregularities may not be corrected so well that they don't
    > affect the image.


    That isn't possible. Defects always degrade the image.

    > I'd be surprised if, except in exceptional
    > cases, the residual irregularites can be separated from the
    > image and the true noise.


    I'd be surprised if they couldn't. It's not rocket science.

    --
    Transpose mxsmanic and gmail to reach me by e-mail.
    Mxsmanic, May 7, 2006
    #7
  8. Marvin <> wrote:
    >fishfry wrote:
    >> Interesting! They can use the noise in an image to id the
    >> exact camera the image came
    >> from. http://dsc.discovery.com/news/briefs/20060501/digitalnoise_tec.html

    >
    >My remarks apply only to the news item. I haven't read the
    >eoriginal publication.
    >
    >By technical definition, noise is random.


    A false premise that invalidates your entire statement.

    >Therefore, noise in a
    >camera does not repeat from photo to photo. There are
    >irregularities in the sensor response that, in a good camera,
    >are mapped and corrected by software. Some irregularities may
    >not be corrected so well that they don't affect the image. I'd
    >be surprised if, except in exceptional cases, the residual
    >irregularites can be separated from the image and the true noise.


    --
    Floyd L. Davidson <http://www.apaflo.com/floyd_davidson>
    Ukpeagvik (Barrow, Alaska)
    Floyd L. Davidson, May 7, 2006
    #8
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