Monocular Vision-Based Multiparameter Dynamic Calibration Method Used for the Low-Frequency Linear and Angular Vibration Sensors

Abstract

The low-frequency linear and angular vibration sensors have been gradually used in many applications of vibration monitoring because they can measure dynamic displacement and angle. These sensors must be calibrated before they are used and after they have been used for a period to ensure their measurement accuracy. Currently, the laser interferometry (LI) and sensor-based comparison method are commonly used to calibrate their sensitivities. However, the former suffers inevitably drawbacks in low- frequency range, while the latter usually has only a limited range, these undoubtedly limit their wide application. In this study, a new monocular vision-based multi-parameter calibration method is investigated, which can determine the sensitivities of these sensors in a broad low-frequency range. The monocular vision method with improved line segment detector (LSD) is applied to measure the linear and angular vibration excitations by extracting the motion feature edges with sub-pixel accuracy. This investigated method strongly promotes the perfection and unification of linear and angular vibration calibration. Many comparison experiments with the LI, the Earth's graviation (EG) method, and the circular grating (CG)-based method confirm that the investigated method gets the satisfactory accuracies in the linear and angular vibration calibration with an efficient, flexible, and low-cost system in the low-frequency range.