FAQ

How are Radiances calculated?

The values given for GAIN and BIAS in the header are not the GAIN and BIAS as expected. These values are L_min and L_max, given in units of mW/(cm*cm)/str/micron, where BIAS is L_min and GAIN is L_max.

           D
L_rad = -------  * ( L_max - L_min ) + L_min
         G_max

where:
    L_rad is the radiance,
    G_max : 255 for radiometrically corrected and higher level products
            63  for PAN in case of uncorrected raw products
            127 for LIS in case of uncorrected raw products
            127 for WiFS in case of uncorrected raw products
    L_max is the maximum saturation radiance
    L_min is the minimum saturation radiance
    D     is the DN from the image