Seismic structural displacement measurement using a high-speed line-scan camera: experimental validation

This paper examines high speed line-scan cameras as a robust and high speed displacement sensor for various seismic monitoring applications. They have the additional benefit of requiring no invasive mechanisms or added processing to provide a high resolution output measure, and do not interfere architecturally. Following the method proposed by Lim et al. for measuring foundation pile movements, multiple displacements and motions of any structure can be determined in real-time at rates over 1 kHz using only one high speed line scan camera and a special pattern. This resolution is more than sufficient for structural monitoring and control problems. Versatility of the proposed measurement technique is examined through both harmonic and random vibration experiments with a suite of different input motions applied to a computer controlled cart. Comparing the input and the measured motions confirms that vision- based structural displacement measurement utilizing a high speed line-scan camera offers a high resolution and low-cost means of measuring structural vibration-displacements.