generate a white matter probability mask from the DW images.
| -grad encoding | specify the diffusion-weighted gradient scheme used in the acquisition. The program will normally attempt to use the encoding stored in image header. 
| encoding | the gradient encoding, supplied as a 4xN text file with each line is in the format [ X Y Z b ], where [ X Y Z ] describe the direction of the applied gradient, and b gives the b-value in units (1000 s/mm^2). |  | 
| -margin width | specify the width of the margin on either side of the image to be used to estimate the noise level (default = 10). | 
| -info | display information messages. | 
| -quiet | do not display information messages or progress status. | 
| -debug | display debugging messages. | 
| -help | display this information page and exit. | 
| -version | display version information and exit. |