A machine-vision system to measure the parameters describing the performance of a Foucault pendulum

Abstract

We describe a machine-vision system that makes real-time measurements of the kinematics of a Foucault pendulum. Images are taken from a downward-facing camera placed close to the pendulum suspension point. The bob is detected via background subtraction and located by fitting circles to the resulting contour segments. The bob trajectory is then modelled by fitting ellipses to recent positions. Parameters are improved through Kalman filtering. Experimental results are shown. Our implementation is a robust and accurate tool for visualization of the pendulum kinematics as well as troubleshooting and maintenance of the mechanical elements.