Most data will extract well using a single profile determined using the average over all orders. If per-order profiles are required then set TUNE_USE_NXF=1.
Profiles are normally determined by calculating the average behaviour at each point in the spatial direction (subsampled, to change the subsampling set TUNE_PFLSSAMP to the number of subsamples in the entire spatial profile, i.e., within the dekker limits).
Profiles may optionally be determined by fitting polynomial/spline functions at each subsampled spatial position. To select this (CPU intensive) method use the parameter TUNE_OBJPOLY to specify the degree of the fitting function to be used).
A typical interactive plot appears below.
Martin Clayton