can someone tell me how the parameters were determined based on a feat job for susan command line?

I see the command run from the log webpage. but i couldn't figure out how the two values were computed.

I have copy&pasted part of the log here. the two values were highlighted in red (the line calls up susan command)

Thanks

Tony

/usr/share/fsl/5.0/bin/fslstats prefiltered_func_data_bet -p 2 -p 98
0.000000 512.334900 

/usr/share/fsl/5.0/bin/fslmaths prefiltered_func_data_bet -thr 51.23349 -Tmin -bin mask -odt char

/usr/share/fsl/5.0/bin/fslstats prefiltered_func_data_st -k mask -p 50
419.969757 

/usr/share/fsl/5.0/bin/fslmaths mask -dilF mask

/usr/share/fsl/5.0/bin/fslmaths prefiltered_func_data_st -mas mask prefiltered_func_data_thresh

/usr/share/fsl/5.0/bin/fslmaths prefiltered_func_data_thresh -Tmean mean_func

/usr/share/fsl/5.0/bin/susan prefiltered_func_data_thresh 314.97731775 2.12314225053 3 1 1 mean_func 314.97731775 prefiltered_func_data_smooth

/usr/share/fsl/5.0/bin/fslmaths prefiltered_func_data_smooth -mas mask prefiltered_func_data_smooth

/usr/share/fsl/5.0/bin/fslmaths prefiltered_func_data_smooth -mul 23.8112383888 prefiltered_func_data_intnorm

/usr/share/fsl/5.0/bin/fslmaths prefiltered_func_data_intnorm -bptf 25.0 -1 prefiltered_func_data_tempfilt

/usr/share/fsl/5.0/bin/fslmaths prefiltered_func_data_tempfilt filtered_func_data

/usr/share/fsl/5.0/bin/fslmaths filtered_func_data -Tmean mean_func