SECTION./AVER
AVERAGE/AVERAGE [in_specs] [out_specs] [out_opt] [draw_flag]
	compute average over subimage
SECTION./COLU
AVERAGE/COLUMN  out = in [start,end] [SUM]
	average image columns
SECTION./IMAG
AVERAGE/IMAGES out = in_specs [merge] [null] [av_option] [dat_intval]
	average images
SECTION./KAPP
AVERAGE/KAPPA [in_specs] [out_specs] [out_opt] [draw_flag] [no_iter]
	compute average (kappa-sigma clipping) over subimage
SECTION./MEDI
AVERAGE/MEDIAN [in_specs] [out_specs] [out_opt] [draw_flag]
	compute average (median value) over subimage
SECTION./ROW
AVERAGE/ROW out = in [start,end] [SUM]
	average image rows

SECTION./WEIG
AVERAGE/WEIGHTS out = in_specs [merge] [null] 
	average weighted images
SECTION./WIND
AVERAGE/WINDOW out = in_specs [meth] [bgerr,snoise]
	compute average of (consistent) pixel values
