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Poisson Noise [message #75481] Fri, 11 March 2011 16:54 Go to previous message
M. Katz is currently offline  M. Katz
Messages: 69
Registered: May 2005
Member
I'm wondering if anyone has a ready-made Poisson-noise simulator for
images that works in the following way.

Start with a simulated ideal image as input, where each pixel contains
a number of photons as the intensity. It could be integer or floating-
point. Then use a function P(img) to return a Poisson-noise-added
version of the image. The key is that noise at each pixel scales with
the intensity appropriately, and not uniformly.

For large numbers of photons, where the Poisson noise has an RMS of
Sqrt(N) and behaves like a Gaussian distribution, I could just add
noise to img1 like this

img2 = 0L > ROUND( img1 + RANDOMN(seed, Nx, Ny)*SQRT(img1) )

But for low photon numbers, this approximation isn't valid.

Thanks,
M.
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