Movable rod position locating method e.g. for earth moving machine, involves calculating position of rod from sensed images and determining location of rod corresponding to markings on surface of rod

摘要

A pair of images corresponding to two different portions of the surface of a movable rod (10) are sensed. The position of the rod is calculated based on sensed images. A determination is made to judge whether the rod is at location corresponding to the markings (12) on the surface (11). An error associated with the position of rod is eliminated when rod is at position corresponding to one of the markings. Independent claims are also included for the following: (1) location monitoring system; and (2) mark forming apparatus.