Single State SAM Images

Dual State SAM Images

With the -D3 option, SAMsrc outputs a pseudo-F value for each voxel. This value is computed from the (estimated) ratio of power in the active window to the power in the control window:

Thus, equal power estimates in the active and control windows would result in . Because the ratio must be positive, power increases in the active window result in values in the range , while power decreases result in values in . To compensate for the difference in size of these ranges, SAMsrc uses a transformation to equalize them:

Equal power estimates in active and control windows result in , active greater than control has , and means that active power was less than control power (or equivalently, control power was greater than active power — SAM is entirely symmetric in this respect).