Radiometric resolution
Topic: Remote Sensing, GIS and GNSS · NCERT: Class 11, Ch 6 "Introduction to Remote Sensing"
Meaning
Radiometric resolution is how well a sensor can tell apart small differences in the energy coming from objects. It is counted as the number of grey levels the sensor can record, from darkest to brightest. More grey levels let the sensor separate surfaces that look almost the same, such as two crops or clear and slightly muddy water. Grey levels depend on the number of bits used to store the data. Modern sensors use 10 to 12 bits.
Example
India's IRS LISS sensors record 0 to 127 grey levels (7-bit data). Landsat TM and SPOT record 0 to 255 (8-bit data). This means TM can pick out finer differences in brightness than LISS.
Don't confuse with
- Spectral resolution: how many wavelength bands a sensor records and how narrow they are. Radiometric resolution is about how finely it measures brightness within a band.
- Spatial resolution: the ground size of one pixel.