Geometric Variables III: Object Detection, Proximity, Presence, Nonpresence

As pointed out in an earlier article on “Position, Motion, Speed, Velocity,” position is central among the geometric variables. Generally1, in position control and motion systems, control action is taken to establish a position or series of positions that lie along a trajectory or path. In these cases the exact coordinates of position are usually paramount. In object detection, exactness of position is not usually the case (but there are exceptions)—the primary purpose being that of detecting the presence or absence of an object.