Biomedical Engineering Reference
In-Depth Information
Fig. 1 Bone tissue within one MRI slice is highly inhomogeneous
Fig. 2 Inhomogeneity of a particular bone tissue across MRI slices is significant
process being controlled in this work is the variational active contours segmenta-
tion; the segmentation is automatic once initialized by the user. A control loop
involves computing the error between the desired reference signal
c
ref
and the
current plant output
c
curr
and feeding it back to the controller, which computes a
control signal
u
designed to drive the plant output toward the reference signal.
Human supervisory control describes the interaction of an automatic process or
task with a user who periodically guides it toward a desired set-point by providing
additional input [
3
]. The automatic process is monitored by the user and corrected if
it deviates from the desired behavior. An example from medical imaging is [
4
]
where the authors created a graphical user interface (GUI) and used it to help
position a model of a knee implant. User input is used to perturb the automatic
registration algorithm when it is trapped in a shallow local minimum or picks a
minimum that is biomechanically incorrect.
