The Application Study of Side Scan Sonography on Steep Side-slopes.
Date Issued
2016
Date
2016
Author(s)
Deng, Fu-Xian
Abstract
Traditionally side scan sonar underwater topography exploration and achieved good acoustic image, identifying the target, seabed texture and ripples through the back scattering signal characteristics, and can be cross-referenced with the multibeam terrain data, but It is usually carried out in a relatively flat area. Many things are built man-made underwater terrain located along the coast, or also on the underwater slope, for example: embankments, embankment dam reservoirs, hydroelectric facilities and so on. On a slope in order to make the image clearer side-scan sonar, past research indicates that the main tone mapping according to the slopes and side-scan sonar beams pointing to adjust the angle of rotation and drag fish ranging study the angle of rotation of the imaging geometry, in accordance with tow fish on the imaging direction of rotation can be divided into reverse and forward slope side slope side, when the rotation angle, when appropriate, will be able to show a good side-scan sonar image, but when the rotation angle difference between the two but when too large, improper easily lead to uneven distribution of the strength of the image, on the slope of the landscape it is difficult to identify the problem, drag the rotation angle of larger fish, so the sound beam reverse side of the slope toward the water surface firing in imaging, reflecting forward image slope side is also more recognizable on the forward side of the slope difference. In addition, in order to make the slope image mapping, drag to rotate the direction of the fish to make video recording more clearly, but also likely to cause error image on positioning, not directly match the multibeam terrain, this study swash fight the imaging geometry, calculate tow fish is pointing downward position, adjust the actual position of the tow fish space through projection plane way to obtain sound reflection point and elevation values on a slope in the cross-sectional every ping sent sound waves, calculate the reflection point fish and drag the distance from the projected point and re-exported into a new coordinate system, so we can match the depth and data together with the side-scan sonar images, results not only in the image not only get to read on the slopes landform image data, terrain information can be read simultaneously. In this paper, this method is applied to hydroelectric facilities on the slope of the Sun Moon Lake, through this way to draw water inlet and outlet fence and embankment dam image, and analyze their results.
Subjects
Side scan sonar
Multi beam
Steep Side-Slope
Sonography
Acoustic application
Type
thesis
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