The STL is a one-dimensional array containing the number of measurements rejected from the comb-addition steps, X substeps, Y steps, and repeats ('slices' or 'bins'). The rejection is controlled by a threshold value, which is indicated in the UDL header file as the keyword, 'YNOISELM'. Sceince Trailer Line files are identified by the extensions ``.D1H'' and ``.D1D''.
