Set to TRUE if the flat-field frame supplied has already been pre-processed to contain balance factors for the pixel-to-pixel variations.
If TRUE, flat-field modelling will not take place and the balance factors will simply be copied from the supplied frame. This should be used for cases where the polynomial model cannot generate appropriate values.
NOTE: The removal of the blaze function is a separate operation and will require the use of the original, raw flat-field frame (or equivalent).
Martin Clayton