Acoustic methods have long been used to rapidly and synoptically survey marine organisms of ecological and economic importance. Direct sampling furnishes biological data such as abundance, biomass, direct measurements of organism size and species identification, but encounters problems such as net avoidance, small sampling volumes, and catch destruction of delicate specimens. Understanding the scattering mechanisms of fish is challenge due to the fact that fish anatomy is complex and the acoustic scattering characteristics are correspondingly
complex. For example, (Nash,1987) qualitatively illustrated the
influence of the various anatomical components of fish on scattering by performing length-wise acoustic scans of whole fish, dissected swimbladders. The swimbladder is the main control factor of fish¡¦s floating and diving. This research will carry on the measure the target with acoustic characteristic of imitative air swimbladder of Tsuchida Seisakusho. We use the imitative air swimbladder and collocate the Reversed Engineering to measure the Backscattering intensity of the swimbldder which is different medium. We set up experiment in an acoustic water tank of dimension (4mo3.5mo2m) located in National Sun Yat-sen University. The projector and receiver both are transducer of fish finder with directivity and frequency response at 200k Hz. The signal receptor used Data Acquisition System of NI 6129 with sample rate at 800kHz. The target set up of this research is referring to (Timothy K. Stanton,2004), and we use servo motor to control the incidence angle of the target. Preliminary research is pointed out, the target strength will change by the incidence geometry of the target, and the target diameter is the factor of the target strength.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-1224108-141654 |
| Date | 24 December 2008 |
| Creators | hsien-Chou, Hsin |
| Contributors | Chen-fen Huang, Jin-Yuan Liu, Shiau-shen Liu |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-1224108-141654 |
| Rights | unrestricted, Copyright information available at source archive |
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