Signal-to-noise ratio (imaging)

Traditionally, SNR is defined to be the ratio of the average signal value ${\displaystyle \mu _{\mathrm {sig} }}$ to the standard deviation of the signal ${\displaystyle \sigma _{\mathrm {sig} }}$:[2][3]

${\displaystyle \mathrm {SNR} ={\frac {\mu _{\mathrm {sig} }}{\sigma _{\mathrm {sig} }}}}$

when the signal is an optical intensity, or as the square of this value if the signal and noise are viewed as amplitudes (field quantities).

• Coefficient of variation
• Contrast-to-noise ratio
• Minimum resolvable contrast
• Minimum resolvable temperature difference
• Optical transfer function
• Signal-to-noise ratio
• Signal transfer function

• ISO 15739:2003, Photography – Electronic still-picture imaging – Noise measurements: specifies methods for measuring and reporting the noise versus signal level and dynamic range of electronic still-picture cameras. It applies to both monochrome and colour electronic still-picture cameras.
• ISO 12232:2006, Photography – Digital still cameras – Determination of exposure index, ISO speed ratings, standard output sensitivity, and recommended exposure index: specifies the method for assigning and reporting ISO speed ratings, ISO speed latitude ratings, standard output sensitivity values, and recommended exposure index values for digital still cameras. ISO 12232:2006 is applicable to both monochrome and colour digital still cameras. It revises ISO 12232:1998.