Three-Dimensional Structural Displacement Estimation Using a Low-Cost Sensing System Combining a Consumer-Grade Camera and an Accelerometer

The monitoring of structural displacements is crucial because displacements can reveal critical information about the health of civil structures. Despite this, accurate measurements of structural displacements remain a difficult task. The fusion of a vision camera and an accelerometer has previously been explored to estimate structural displacements, but only in-plane displacements can be estimated. This chapter describes a three-dimensional structural displacement estimation method that fuses measurements from a consumer-grade camera and a triaxial accelerometer mounted on a target structure. An accelerometer-aided computer vision algorithm and an adaptive multirate Kalman filter are integrated to efficiently estimate high-sampling three-dimensional displacements from low-sampling vision measurements and high-sampling acceleration measurements. All parameters associated with the computer vision algorithm are automatically calibrated without any prior knowledge or ad-hoc thresholding. Experimental validation of the proposed method is performed on a four-story building model under varying excitations. Displacements were accurately estimated with a root mean square error of less than 2 mm.