Radiometric resolution can be defined as the ability of an imaging system to record many levels of brightness. Radiometric resolution refers to the range in brightness levels that can be applied to an individual pixel within an image, determined on a grayscale. E.g., Sentinel-2 sensor MSI is a 12 bit sensor imaging with 4.096 levels.
Radiometric resolution is defined as the sensitivity of a remote sensing detector to differences in signal strength as it records the radiant flux reflected, emitted, or back-scattered from the terrain.