input,s,a,,,,         "input file(s)"
output,s,a,,,,        "output files"
x1,i,h,INDEF,1,,          "x1,x2,y1,y2 specify section of image to\n\
use to calculate the mean value"
x2,i,h,INDEF,1
y1,i,h,INDEF,1
y2,i,h,INDEF,1
upper,r,h,INDEF,,,        "upper value of pixels to use for mean (or INDEF)"
lower,r,h,INDEF,,,        "lower value of pixels to use for mean (or INDEF)"
mode,s,h,al