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In this section, we will talk about two different processing levels, L1B Top of Atmosphere Radiance, and L2A Bottom

Hyperspectral imaging uses a narrow range of wavelengths across the electromagnetic spectrum, to produce images of the Earth's surface. These images contain information about the reflectance of each pixel across the electromagnetic spectrum. How each pixel reflects light can tell us a lot about the materials that are present within a pixel.

An Earth observation sensor reads the intensity of the electromagnetic spectrum collected within each pixel as a digital number (DN). These DNs represent the surface reflectance from the Earth plus contributions from atmospheric gas absorption, atmospheric scattering, variations in illumination from topographical features, instrument response curves and other artifacts. This is to say, DNs are not surface reflectance! DNs are data that require radiometric processing in order to obtain images with physically meaningful quantities like radiance or reflectance.