Radiometric resolution relates to how much information is perceived by a satellite’s sensor. While the human eye detects color, Landsat sensors measure energy reflecting or emitted from the earth and relay that information as an image to users in varying degrees of greyscale. The higher the radiometric resolution, the more shades of grey the user sees.
Landsat data are characterized by digital numbers. A 4-bit image indicates there are 16 digital values available ranging from 0 to 15. A 16-bit resolution image indicates there are 65,536 potential digital numbers between 0 to 65,535 for that sensor to record information. Since Landsat imagery is acquired in greyscale, the minimum (lowest) value is represented as black, and the maximum (highest) value is represented as white. Comparing a 4-bit image to a 16-bit image shows notable differences within the greyscale.