- 學位論文
超音波技術應用於迴響水槽中物體特性量測
Characterization of underwater organisms using ultrasonic inspection techniques in reverberant cavity
摘要
超音波水下生物特性量測是一門在發展的技術，它是一種對生物體幾乎無傷害的量測方法。傳統的超音波水下生物量測技術主要應用在一個廣闊的海洋。但是對於反射邊界條件下並不適用，依據學者的研究，在高度反射邊界的水槽中以超音波的方法量測魚群特性，實驗過程的優點在於不會去打擾或傷害到魚群活動。其主要原理是利用發射及接收超音波進入有魚群的水槽中，以接收到的時間域下連續訊號，計算出魚群的全散射斷面係數，進一步算出總目標強度，而建立總目標強度與魚群數量的關係式，量測魚群的總目標強度來估計生物體的數量。 不同的魚群種類有不同的總目標強度，要了解更多生物的特性就需要建立更多的資訊。本文由量測實體金屬球的總目標強度做正確性的確立，之後，我們利用這個基本理論以不同的物種(朱文錦魚、日光燈魚及黃金斑馬魚)作為生物實驗的量測，量測生物體的訊號特性，建立魚群與總目標強度的關係式，計算不同數量的魚群所對應的總目標強度，由量測總目標強度就可反推出該魚群的數量。最後建立這三種不同的魚群物種對應的總目標強度的物種資料庫。
並列摘要
Characterization of underwater organisms by ultrasonic techniques has been under development. It is a harmless technique to monitor underwater organisms. In a previous study, ultrasonic measurement was used to monitor non-invasively the number of fishes and even growth rates in the future that under highly reflecting boundaries. These measurements were performed remotely, without human interaction with the fish. Recently, it has been demonstrated that the acoustical total scattering cross section of fish swimming in a basin can be measured from multiple reverberation time series. These measurements have been used successfully to estimate the number of fish in a tank in laboratory conditions. In this thesis, a reference study of correctness and accuracy was made with the measurement of the total target strength of solid metal balls. After the confirmation of the accuracy of the study, the above basic theory mentioned was applied. Different kind of species (such as Shubunkin Goldfish, Neon Tetra fish and Golden Zebra fish) was used as the organism measured to identify the characteristic signals magnitude in the study. Further, the calculation of the different number of fish corresponded total target strength was made. Finally, the measurement of corresponded total target strength to the three species of fish was made. By these information, an effective species database was established.