2011 Fiscal Year Final Research Report
A Study of Acoustic Lens for Imaging Target Object Using Ocean Ambient Noise
| Project/Area Number |
21360440
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Naval and maritime engineering
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| Research Institution | 防衛大学校 |
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Principal Investigator |
MORI Kazuyoshi 防衛大学校, 応用科学群, 准教授 (70259894)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Toshiaki 防衛大学校, 応用科学群, 教授 (50089885)
OGASAWARA Hanako 防衛大学校, 応用科学群, 助教 (00531782)
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| Project Period (FY) |
2009 – 2011
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| Keywords | 海洋科学 / 海洋工学 / 海洋探査 / 音響レンズ / 海中周囲雑音 / 物体映像化 / 沿岸域生物雑音 |
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| Research Abstract |
Ambient noise imaging(ANI) is the novel idea to utilize natural ocean ambient noises positively. We designed and fabricated an aspherical lens with an aperture diameter of 1.0 m to develop a prototype system for ANI. It was also verified that this acoustic lens realizes a directional resolution, which is a beam width of 1 degree at the center frequency of 120 kHz over the field of view from-7 to+7 degrees. The sea trial of silent target detection using the prototype ANI system was conducted under only natural ocean ambient noise at Uchiura Bay, in November of 2010.We proposed a classification method to extract transients of only target scatterings from many transient noises. By analyzing transients extracted as target scatterings, it was verified that the power spectrum density levels of the on-target directions were greater than those of the off-target directions in the higher frequency band over 60 kHz. These results showed that the targets are successfully detected under natural ocean ambient noise, mainly generated by snapping shrimps.
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Research Products
(22 results)
