Monocular vision-based radial vibration measurement system for rotating shafts using angular mirror imaging

Radial vibration signals of rotating machinery shafts are crucial dynamic indicators for assessing structural health condition. Visual measurement has emerged as a widely adopted technique for capturing vibration information, however, existing methods typically rely on artificial markers, limiting their scalability and robustness. To address this limitation, this paper presents a markerless monocular visual measurement system based on angular mirror imaging. A high-speed camera captures the mirror-generated virtual image of the rotating shaft, and an energy centrobaric-based edge detection method is employed to precisely locate the shaft position in each frame. Subsequently, a dedicated angular mirror imaging algorithm is used to extract radial vibration displacement with high accuracy and efficiency. The feasibility of the proposed approach is validated through simulation experiments, and the key parameters affecting measurement performance are systematically analysed. Comparative experiments with eddy current sensors demonstrate that the proposed method achieves two-dimensional vibration monitoring using a single angular mirror, while offering a simplified structure, high precision, and enhanced robustness. The system holds significant potential for applications in dynamic behaviours analysis, condition monitoring, and fault diagnosis of rotating machinery.