Avoiding Camera Noise Signatures

Step 3 Crop and resize the image

If you have dirt on year lens, dead pixels or "hot" pixels, then it is really easy to find images from the same camera since they will all have static pixels. This means, from image to image there will always be a handful of pixels that don't change.

The way to get around this is by cropping and resizing the image. This will shift the position static pixels and when images are compared together make them just seem like noise.

This alone will not always remove the noise signature itself, but it is one way to make it harder to identify it.

Comments

[u_eco]

I suggest either nearest neighbour or lanczos interpolation when scaling images. Lanczos is based on "ideal" sinc filter and can be configured as low-pass filter that removes noise (the statistical signature).

For example, using lanczos interpolation when scaling image in GIMP, it screws up higher frequencies (the visible noise) quite considerably (measured with power spectral density and correlated to original image).

See attached example measurement (shows PSD and correlation of frequencies spectrum after Fourier transform).

[u_eco]

Here is direct link to image showing PSD and correlation, since instructables downsized it.