Event-based micro vibration measurement using phase correlation template matching with event filter optimization

Abstract

Condition monitoring of mechanical systems based on vibration is one of the most effective and useful techniques for predictive maintenance. With advancements in image processing and artificial intelligence technologies, vision camera-based condition monitoring has come into the spotlight. An event camera, also called a dynamic vision sensor, operates on a principle different from that of traditional frame-based cameras. However, there is still no standardized method for event camera-based vibration measurement. This study proposes an event filter-based phase correlation template match (EF-PCTM) method, including its optimal design procedure, to measure micro-vibrations using an event camera. In this study, event filter is designed using an infinite impulse response filter and genetic algorithm, and a cost function is defined to improve the performance of EF-PCTM. The performance of the proposed method was verified by two experiments using a rotor system simulator: i) extraction of micro-vibration and ii) fault condition monitoring. The proposed image processing procedure using EF-PCTM makes it possible to measure micro-vibrations, which had been challenging to measure in the past, and calculate the operational deflection shape.