Non-contact and Real-time Dynamic Displacement Monitoring using Smartphone Technologies

Many of the available approaches for Structural Health Monitoring (SHM) can benefit from the availability of dynamic displacement measurements. However, current SHM technologies rarely support dynamic displacement monitoring, primarily due to the difficulty in measuring absolute displacements. The newly developed smartphone application in this study allows measuring absolute dynamic displacements in real time using state-of-the-art smartphone technologies, such as high-performance graphics processing unit (GPU), in addition to already powerful CPU and memories, embedded high-speed/resolution camera, and open-source computer vision libraries. A carefully designed color-patterned target and user-adjustable crop filter enable accurate and fast image processing, allowing up to 120Hz frame rate for complete displacement calculation. The performances of the developed smartphone application are experimentally validated, showing comparable results with those of conventional laser displacement sensor.

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