Detecting displacement of point within given reference frame, especially for tracking potential displacement of points in soil by attaching illuminated object to point and observing from two video cameras

摘要

The point (1) considered likely to move along a path (3) has an illuminated object (10) attached to it by suitable means (11). Light from the object travels along an axis (30) to a focussing objective (12) and focal plane (14) which may be a CCD video camera. The camera output is processed in a microcomputer (18) and used to operate an alarm (19). A second camera (12',14') may also be used to detect movement along the first camera axis.