Keywords

Vision, Vibration Measurement, Civil Structures, LabVIEW, Photogrammetry, Non-contact

Presentation Type

Event

Research Abstract

Photogrammetry is one of the most promising non-contact, vision-based measuring techniques. It became commercially available as a result of the development of digital cameras and computer processing technology. Vision-based technique has wide applications in civil engineering such as deflection measurement or condition inspection. However, these applications focus more on static measurements because of the limitations of the acquisition frame rate and the resolution of the image sensor. Developing measurement systems using newly developed equipments and software can enable this technique to be applied to more fields. In this project, a vision-based vibration measurement system for characterizing civil structures is developed under LabVIEW environment. The major apparatus include two recently released machine vision cameras (Basler acA2040-180kc) with high resolution (4M pixels) and frame rate (180Hz), and a Camera Link image acquisition board (NI PXIe-1435). First, the test structure is modeled in 3-D by a photogrammetric software called PhotoModeler. Second, the measurement locations are determined by the dynamic characteristic of the structure. Then consecutive pictures of the test structure are taken and sent to the LabVIEW program to obtain the vibration data. At last the measured parameters are compared to the measurements of contact sensors. The results show that the obtained parameters are comparable to the contact measurements. In conclusion, photogrammetry is a considerably accurate non-contact measuring method. This project mainly focuses on the measurement part and the analysis of the acquired data is left for future study.

Li Tong_SURF 2013_Symposium Presentation Slides.pdf (2206 kB)
Li Tong SURF 2013 Presentation Slides

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The Development of a Vision-Based Vibration Measurement System for Characterizing Civil Structures

Photogrammetry is one of the most promising non-contact, vision-based measuring techniques. It became commercially available as a result of the development of digital cameras and computer processing technology. Vision-based technique has wide applications in civil engineering such as deflection measurement or condition inspection. However, these applications focus more on static measurements because of the limitations of the acquisition frame rate and the resolution of the image sensor. Developing measurement systems using newly developed equipments and software can enable this technique to be applied to more fields. In this project, a vision-based vibration measurement system for characterizing civil structures is developed under LabVIEW environment. The major apparatus include two recently released machine vision cameras (Basler acA2040-180kc) with high resolution (4M pixels) and frame rate (180Hz), and a Camera Link image acquisition board (NI PXIe-1435). First, the test structure is modeled in 3-D by a photogrammetric software called PhotoModeler. Second, the measurement locations are determined by the dynamic characteristic of the structure. Then consecutive pictures of the test structure are taken and sent to the LabVIEW program to obtain the vibration data. At last the measured parameters are compared to the measurements of contact sensors. The results show that the obtained parameters are comparable to the contact measurements. In conclusion, photogrammetry is a considerably accurate non-contact measuring method. This project mainly focuses on the measurement part and the analysis of the acquired data is left for future study.