6. Radiometric resolution and correction
Radiometric resolution
The radiometric resolution refers to how much information is contained within the image – effectively what the bit-depth is.
An image may be 8 bit, 16 bit or 32 bit.
Radiometric correction
The radiometric correction is the process of correcting the colour and brightness of the image to take out spectral distortion.
When light passes through the atmosphere some wavelengths are absorbed or reflected more than others.
There are two main types of correction for this:
Top Of Atmosphere (TOA) correction; based on the known position and angle of the satellite and the sensor
Full Atmospheric Correction (FAC); based on knowing the composition of the atmosphere at the time of the image.
Getting a true FAC is usually difficult in Antarctica, as we rarely know the composition of the atmosphere. But luckily, the levels of aerosols and other pollutants are small, so usually a TOC correction will suffice.
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