more pixels are better!

Started Dec 14, 2008 | Discussions thread
Les Olson Senior Member • Posts: 2,081
Re: Are those figures for "print" or "screen"? (nt)

ejmartin wrote:

How pedantic do you want me to be? I do not mean "has image data at
higher spatial frequencies if there are higher spatial frequencies in
the image"; there is always data up to the Nyquist frequency in an
image. The amplitude of the signal at high spatial frequency can be
small if there is no fine scale detail. Such is the case for a
region of uniform tonality.

Well, pedantic enough to remember that the whole and sole basis of saying that SD of pixel output is "noise" is that noise is the only cause of variation of pixel output.

You cannot call SD of pixel output "noise" when there is variation among pixels due to signal variation (ie, image modulation). You cannot calculate pixel SD from an image with both (photon + read + dark) noise and signal variation and label that "noise".

Of course there are high frequency components in noise: the distribution of the pixel outputs only approximates to Normal, however much the sample size increases. And as sample size gets smaller the distribution gets rougher, but it would be absurd to call that statistical noise sensor noise.
2 November 1975.

'... Ma come io possiedo la storia,
essa mi possiede; ne sono illuminato:
ma a che serve la luce?'

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