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A Study On Acoustical Classification Of Sediment

Posted on:2004-02-20Degree:MasterType:Thesis
Country:ChinaCandidate:D Z GaoFull Text:PDF
GTID:2120360092496676Subject:Acoustics
Abstract/Summary:PDF Full Text Request
Sea bottom classification has a great perspective on civil engineering and on military engineering. In civil engineering applications, for example harbor-constructing and bridge-building, need information of sea bottom. In military engineering applications, identification of sea bottom types are vary important for match field location, low-frequency sonar distance forecast, and choosing the location for submarine.In this thesis, a study on the sea bottom classification by using acoustical method is made. Two kinds of methods were used: acoustic impedance inversion (All) method and statistical characters extraction (SCE) of sound echo method. In All method, the precision and stability of inverse results have been improved through mending the impulse response technique. A Lab-experiment is made to verify the precision of the All. The relative error of inversed impedance for sound pulse tube data is 1.3% approximately. In SCE method, a sub-band frequency energy technique has been improved and a new technique which is based on phase plane technique has been proposed. Four characteristic quantities have been extracted and used in data-analysis.By using these two methods hereinbefore, we have dealt with sound pulse tube data and 200-set survey data of sea bottoms of five positions. We summarize the results as follows:1) The All of surface layer sediment can be used on the sea bottom classification. Although inversed results of the sea bottom data have a certain errors, it indeed shows that there is a remarkable diversity between the sea-beds: sand-type and silt-type.2) The SCE shows potential of the application for sea bottom classification. Both the improved sub-band frequency energy technique and the phase plane technique can distinguish completely the sea-beds: sand-type and silt-type.
Keywords/Search Tags:acoustical impedance inversion,sound pulse tube, statistical characters, sub-band frequency energy, phase plane
PDF Full Text Request
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