Fully automated natural frequency identification based on deep-learning-enhanced computer vision and power spectral density transmissibility

As image acquisition devices have outstanding potential for gathering vibration information, computer vision has received a lot of interest in structural health monitoring (SHM). In this work, a fully automated peak picking methodology based on computer vision in tandem with deep learning is proposed to realize vibration measurements and identify natural frequencies from the plot of the power spectral density transmissibility (PSDT). A deep-learning-enhanced image processing technology was used to extract the vibration signals with automatic active pixel selection, while a convolutional neural network was used to further process the vibration measurements so that the frequencies could be identified from PSDT-based functions. The proposed method was verified by three case studies, including the dynamic testing of two laboratory models and the field testing of the stay cable. The findings showed that the proposed deep-learning-enhanced approach has a high potential for use in SHM by automatically performing vibration measurement and frequency extraction.