Avoiding Camera Noise Signatures

Step 4 About the noise signature

So far I've only told you how to make it hard to tell a picture has come from your camera, but not how to remove the noise signature. The marks made by dirt on the lens and dead pixels is actually different than the noise signature that they use to keep track of what pictures you are taking.

The noise signature itself is actually due to thermal noise (environmental heat) and imperfections on the CCD itself. Professional photographers and astrophysicists have tried to compensate for this by creating cameras that evenly lights a CCD a moment before the image is taken to create a noise reference against the image being taken or by super-cooling the camera itself so that heat can't distort the CCD.

In your store-bought camera, it won't have either of these functions and so you will end up getting a lot of pseudo-random noise mainly on the last 3 bits of every pixel. This noise isn't really noticeable to the naked eye, but with a large enough image sample, they can create a noise profile and match almost with certain accuracy pictures from the same camera. Since the noise is dispersed throughout the image itself and tends to remain constant through certain standard image manipulations, it is hard to remove without destroying the image.

Comments

[elderbear]

This isn't actually pseudo random noise. It is random noise that MAY be biased by process variation between elements of the CCD.