= {
" ",
"Usage: bgradient [options] input.img output.img",
"-----------------------------------------------",
"Calculates image gradients.",
" ",
"Actions:",
"-gaussian 2.4,5.1,20.4   Anisotropic gaussian filter (one value sets all).",
"-gradient 3x3            Gradient type: cd, 3x3, freq.",
"-magnitude               Convert gradient vectors to lengths.",
"-anisotropic 10,0.5      Anisotropic gradient smoothing: iterations and weight.",
" ",
"Parameters:",
"-verbose 1               Verbosity of output.",
"-datatype u              Force writing of a new data type.",
"-sampling 1.5,1.5,1.5    Sampling (A/pixel; a single value can be given).",
"-origin 110,50,44        Origin for the mask (default from input image).",
" ",
NULL
}