A New Optical Sensing Device for Real-Time Noncontact Vibration Measurement Considering Light Field Variation

Vibration measurement is essential for vibration monitoring and control. Noncontact vibration measurement is more applicable in practice than the contact measuring manner, but the noncontact methods usually pose a high requirement in the light field environment. To solve this issue, a new binocular vision method is proposed to enable noncontact vibration measurement with different light fields. In this new method, the multitarget objects in the same image are first recognized by a YOLOv5 model to generate the bounding boxes; meanwhile, a depth image is generated through binocular vision and kept synchronized with the target image. Then, based on each bounding box and its corresponding depth image, an optimal depth value decision algorithm is developed to determine the 3-D real-time coordinates of each object. As a result, the vibration of multitarget objects can be measured simultaneously. An experimental test system was built to evaluate the performance of the proposed method in indoor and outdoor light fields. The tests demonstrate accurate vibration measuring results, and the proposed noncontact method is able to detect very low-frequency vibrations.