Lawrence D'Oliveiro wrote: >> ... but PRNU isn't random noise. > > It is random noise, but only in the spatial domain; it is not > time-varying.
Thank you for that correction as all of this is brand new to me. Regarding my mis-statement of: "I never heard of BM3D denoising/renoising until you mentioned itt, so looking it up, BM3D denoising + re-noising is apparently wonderful for removing random noise, but PRNU isn't random noise." Taking Lawrence's kind-hearted and correct admonishment into account, what I perhaps should have said is that PRNU is indeed random noise in the spatial domain, but it's fixed-pattern noise and time-invariant noise. Therefore, the same pixel-level gain variations show up in every photo from that sensor in the spatial coordinates, which is how they correlate images. That's the distinction I was trying to get at when I implied that my research seems to indicate that BM3D is excellent at removing time-varying random noise, but PRNU behaves like a stable multiplicative gain map. I think BM3D can reduce some PRNU energy, but it might not reliably break the correlation the way geometric misalignment or resampling does. Thanks again to Lawrence and to Piergiorgio for offering useful advice. Your correction helps me phrase it more accurately as all this is new to me, so were learning how to protect our images on the Internet together. -- Privacy is a million technical things, of which most people know about 3. -- https://mail.python.org/mailman3//lists/python-list.python.org
