Signal-to-Noise Ratio (SNR)
The Signal-to-Noise Ratio is calculated from the ratio of the mean signal and the standard deviation of the noise within a region of interest. The higher a signal is above the noise, the higher the SNR value. A high SNR value makes the evaluation of a digital radiographic image easier.
Normalized Signal-to-Noise Ratio (SNRN):
SNR normalized to a Basic Spatial Resolution (SRb). With magnification SNR is normalized to SRbimage, with no magnification it is normalized to SRbdetector.