Tracking the multi-component motion of a cable using a television camera

A realizable, accurate, real-time method for measuring and tracking the multi-component displacement and velocity of a cable under arbitrary dynamic environments is presented. Such measurements are essential for the control and monitoring of smart structures. The approach utilizes a TV camera, commercial x-y tracker and a conventional PC, with a limited number of channels, to give interpolated displacement estimates to within 0.25 cm anywhere on a 15 m cable. The method avoids use of complicated instrumentation cabling, but is limited to structures with frequencies of interest of less than 15 Hz. The measurement approach can perform well in most environmental settings, but may be limited by severe rain or sun interference.