スキャニングソ-ナ-を用いた表中層魚群の三次元分布と形状解析
スキャニングソ-ナ-を用いた表中層魚群の三次元分布と形状解析
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使用扫描声纳对表层和中间鱼群进行三维分布和形状分析
DOI：
10.3135/jmasj.25.240
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
堀内 則孝
中科院分区：
文献类型：
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作者：
飯田 浩二;向井 徹;堀内 則孝
从声束扫描获得的声纳图像通常是二维截面图像。但是，由于可以通过观测船的前进容易地获得断面图像，因此可以通过分析二维断面图像的叠加来重建水下物体的三维图像。在Funka湾，在R/V Ushio Maru上进行了回波调查，该调查配备了180度扇形扫描声纳（型号KCH 1827，Kaijo Co. LTD）。声纳波束垂直于船的航向向下照射。当船只以10节的速度巡航时，垂直剖面声纳图像每1.5秒数字化一次。利用三维图像处理软件SLICER对层叠断面图像进行分析，确定鱼群的空间分布和形状，并通过水平投影和垂直投影的同时表达来显示鱼群的分布。这种表达方法使我们能够观察到鱼类回避船只，这是不能观察到的普通垂直回声测深仪，鱼群的体绘制重建的实体形状可以通过改变视点自由观察。这使得可以确定规模，功能和鱼群的游泳方向。扇形扫描声纳图像的三维显示不仅对于商业捕鱼，而且对于鱼类资源和水下漂流物的科学调查是有用的工具。
Sonar images obtained from a scanning acoustical beam are usually two-dimensional sectional images. However, since the sectional images can be easily obtained as an observation vessel moves forward, we can reconstruct three-dimensional images of underwater objects by analyzing stacked two-dimensional sectional images.The echo survey was conducted in Funka Bay aboard the R/V Ushio Maru, which is equipped with a 180-degrees sector scanning sonar (model KCH 1827, Kaijo Co. LTD). The sonar beam was directed downward perpendicularly to the ship's course. Vertical sectional sonar images were digitized every 1.5 seconds while the vessel was cruising at 10 knots. The stacked sectional images were analyzed to determine the spatial distribution and shape of fish schools using the three-dimensional image processing software SLICER.The distribution of fish schools was displayed by simultaneous expression of both horizontal and vertical projections. This expression method enabled us to observe fish avoidance from vessel, which can not be observed using ordinary vertical echo sounders.The reconstructed solid shape of fish schools by volume rendering could be observed by changing the visual point freely. This allowed to determine scale, features, and swimming direction of the fish schools. Three-dimensional display of sector scanning sonar images is a useful tool not only for a commercial fishing, but also for scientific surveys of fish resources and underwater drifters.