A monocular vision-based decoupling measurement method for plane motion orbits

Abstract

The plane motion that composed of dynamic displacement and angle is the basis of six-degree-of-freedom motion, and its accurate measurement is especially important for the applications of inertial navigation, pose estimation, and bridge structural healthy analysis. Currently, the commonly used measurement strategies include the laser interferometry, grating ruler-based method, and sensor-based method. However, they are always difficult to accomplish the high-accuracy and efficiency measurement in a broad low-frequency range due to the limitation of their performances. In this study, a monocular vision-based method is investigated to measure the plane motion, which can get the displacement and angle as well as orbit simultaneously by using the Zernike moment method with sub-pixel accuracy and decoupling model. The measurement uncertainties of dynamic displacement and angle are 0.266% and 0.098°, and the resolutions can highly reach to 0.1 um and 0.0001°, respectively. Comparison experiments with the laser interferometry and circular grating method demonstrate the investigated method can accomplish high-accuracy displacement and angle measurements in the ranges of 0.05–20 Hz and 0.001–10 Hz. Meanwhile, the different plane motion orbits can also be measured by the investigated method.