- 學位論文
數位攝影與微波雷達在橋梁振動測量的應用
Traffic Loading Tests of a Concrete Bridge Using Digital Image Processing and Microwave Inteferometry
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摘要
本研究的目的在於利用個人電腦和數位攝影器材，將所記錄的大量影像資訊，以數位影像相關係數法進行批次的後處理，從而得到暫態位移紀錄。使用數位攝影與非接觸式微波雷達同時測量混凝土橋梁，在重車經過時二者測得的最大垂直位移，差異在4%~11%之間，也驗證數位錄影機架設位置因環境振動所產生的差異，進一步對數位影像分析所得之位移紀錄做傅立葉轉換，在1~3.3 Hz之間出現數個尖峰頻率，其中受測橋梁的自然頻率約為3.2 Hz，與微波雷達位移紀錄的頻率域分解法(Frequency Domain Decomposition)分析之結果相近。
關鍵字
數位攝影並列摘要
The objective of the current study is to obtain the transient displacement records and thus resonant frequencies for bridges using digital image processing. Traffic loading tests of an 80-meter-long concrete bridge were carried out. The vertical displacements of the bridge caused by a fully-loaded garbage truck were monitored by mid-range digital video recorders and a microwave interferometer simultaneously. The recorded video was later processed and stored as an image sequence. The transient displacement records were then obtained by applying digital image correlation to the image sequence. There exists a 4% to 11% difference in the maximum displacements between measurements resulted from digital image processing and those obtained by microwave interferometry. Such disagreements could be due to unexpected vibration during video recording as further analyses indicated small movements of the digital video recorder. The natural frequency of the bridge, on the other hand, is estimated to be 3.2Hz and agrees with that obtained by microwave interferometry.
並列關鍵字
Digital Image參考文獻
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