An example of the head point computation of the Electrode Axis Estimation step.
(a) in a region R the algorithm looks for a point, C
0, with an intensity value greater than the threshold. If such point does not exist the region size is increased, R
′, until the point is found. In (b) the algorithm compute the center of mass of a region R centered in C
0. This step is iterated, C
, until the point C
is equivalent to C
k−1. In (c) the point C
will be used as head point point (H) in later analysis steps.