Find a threshold for surface display of a volume

• Use TH M to create a mask from the reference

  TH M
  reference_volume   ; input file
  ref_mask           ; output file
  b                  ; BLANK OUT  (A)BOVE OR (B)ELOW THRESHOLD? (A/B)
  25                 ; the known threshold for this reference volume
  

• Use FS to get the average value of the mask, which is used to compute the number of voxels.

  FS [max],[min],[avg]    ; find the average value of the mask
  ref_mask
  
  FI [volsize]        ; get the volume size
  ref_mask
  (1)
  
  [nvoxels] = [avg] * [volsize] * [volsize] * [volsize]
  

• Use FV to compute the threshold for the new volume

  FV [thresh]
  new_volume  ; volume for which you want the threshold
  [nvoxels]
  

• Use the value [thresh] in Web to display a surface view of new_volume