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nobody

03 Iul 2014 22:08



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Zgomotul absolut este irelevant. Tocmai SNR-ul (Signal-to-Noise Ratio) denota cat de zgomotoasa este imaginea fata de semnal.

Sum creste SNR-ul. Dar creste si deviatia standard. Ca urmare imaginea este mai zgomotoasa.
Abordarea autorului din primul link este cam naiva:

"Secondly, take a look at the Standard Deviation for the SUM method (left-most frame) - it is more than double that of the single exposure. This appears to show that the noise is accumulating along with the signal, that there is no noise reduction taking place. Is this surprising or is it intuitive? I have always seriously doubted that the mere accumulation of photons over an extended period can achieve the same S/N ratio as the averaging of multiple sets of random data."

Da, zgomotul a crescut de 2 ori, dar semnalul... de 19 ori :roll: ... iar bietul om confunda SNR-ul cu nivelul de zgomot.