The function converts the reflectance (ref) back to radiance (rad) given that linear conversion coefficients for both radiance and reflectance are available.
convRef2RadLinear(band, refm, refa, radm, rada, szen)
raster::RasterStack or raster::RasterLayer containing reflectance.
Multiplication coefficient for reflectance conversion.
Addtition coefficient for reflectance conversion.
Multiplication coefficient for radiance conversion.
Addition coefficient for radiance conversion.
Sun zenith angle.
raster::Raster*
object with converted values.
The conversion functions are taken from USGS' Landsat 8 Data Users Handbook which is available online at https://www.usgs.gov/land-resources/nli/landsat/landsat-8-data-users-handbook.