Introduce digital quantized value radiance values, an apparent reflectance, surface reflectance and atmospheric correction of the radiometric calibration and knowledge.
Digital quantized value DN: i.e., radiation received at the satellite to a quantized value, meaning there is no specific units.
Radiance Radiance: known emissivity, per unit area, radiant flux per unit wavelength, unit solid angle, can be converted by standard radiation into radiation of a given DN.
The apparent reflectance Reflectance: satellite reflectance, surface reflectance atmosphere, the atmosphere is not corrected, the received satellite reflectance.
Surface reflectance: Feature real reflectance, the reflectance of the apparent reflectance obtained by subtracting the atmospheric effects. Correction can be obtained from the atmosphere, the obtained value as flaash / 10000 to give the surface reflectance.
Moreover, the apparent reflectance spectra radiance is calculated by radiance, atmospheric correction is not performed. Formula = Pi * L * [rho] D * D / (ESUN * cos [theta])
[rho] is the apparent reflectance or reflectance planets, L is the radiance value, d is the distance day, ESUN atmosphere average of the incident solar radiation, θ is solar zenith angle.
Additional information:
1.flaash atmospheric correction inputs must be obtained radiometric calibration radiance
2.quac atmospheric correction input may be raw DN \ reflectance \ radiance ...
3.6s atmospheric correction models subsequent supplements.