Just curious - how is this measured? Does a camera take a photo of a solid color and use that to determine the SNR?
Is this applicable/possible to measure on non-digial cameras (i.e. classic film cameras), or is there an analogous metric to measure their quality?
patrickrz
Is there significance to the SNR having a constant of 20?
Noppapon
I am wondering the same thing as @patrickz. After finding information about the conversion online, some websites say the constant is 20 whereas the others say 10.
sberkun
10 is common to the decibel scale; it's designed such that a x10 increase corresponds with +10 dB (hence the name decibel).
However, decibel is measured in terms of power, and the pixel values are a magnitude. Conventionally power is proportional to magnitude squared (doesn't make much sense in this context, but it did in EE120 when it was in terms of voltage), so the SNR is really
10log10((σμ)2)
which turns into the expression on the slide when you pull the 2 out.
Just curious - how is this measured? Does a camera take a photo of a solid color and use that to determine the SNR?
Is this applicable/possible to measure on non-digial cameras (i.e. classic film cameras), or is there an analogous metric to measure their quality?
Is there significance to the SNR having a constant of 20?
I am wondering the same thing as @patrickz. After finding information about the conversion online, some websites say the constant is 20 whereas the others say 10.
10 is common to the decibel scale; it's designed such that a x10 increase corresponds with +10 dB (hence the name decibel).
However, decibel is measured in terms of power, and the pixel values are a magnitude. Conventionally power is proportional to magnitude squared (doesn't make much sense in this context, but it did in EE120 when it was in terms of voltage), so the SNR is really
10log10((σμ)2)
which turns into the expression on the slide when you pull the 2 out.