日本地球惑星科学連合2018年大会

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[EE] Eveningポスター発表

セッション記号 M (領域外・複数領域) » M-TT 計測技術・研究手法

[M-TT35] 高精細地形・地球物理データ解析

2018年5月20日(日) 17:15 〜 18:30 ポスター会場 (幕張メッセ国際展示場 7ホール)

コンビーナ:早川 裕弌(東京大学空間情報科学研究センター)、Gomez Christopher(神戸大学 海事科学部 海域火山リスク科学研究室)、楠本 成寿(富山大学大学院理工学研究部(理学))

[MTT35-P05] マルチビーム測深とSfM写真測量を組み合わせた精密海底DEM構築:第二次世界大戦時の沈船を例として

*菅 浩伸1片桐 千亜紀2中西 裕見子3吉崎 伸4長尾 正之5小野 林太郎6 (1.九州大学大学院比較社会文化研究院、2.沖縄県立埋蔵文化財センター、3.大阪府教育庁、4.京都市埋蔵文化財研究所、5.産業技術総合研究所地質情報研究部門、6.東海大学海洋学部)

キーワード:多視点ステレオ写真測量、マルチビーム、海底地形、水中文化遺産

The high-resolution digital elevation model (DEM) generation using Structure-from-motion (SfM) photogrammetry is challenging for underwater objects and geomorphology because global positioning systems-based mapping techniques cannot be applied to the seafloor. We eliminate this problem by incorporating precise control points obtained from high-resolution multibeam echosounding bathymetry to generate 3D models using SfM photogrammetry.

A World War II wreck USS Emmons, a 106-m US Navy Benson-class destroyer minesweeper sank in ~40 m of water off Okinawa Island, Japan, is used as a case study for this project. The Sonic 2022 was used for multibeam bathymetry which has a variable ultrasonic frequency of 200 to 400 kHz, 256 ultrasonic beams and selectable swath coverage of 10 to 160 degrees. An ultrasonic frequency of 400 kHz is selected for this study. An ultra-high-resolution DEM with a grid size of ~5 cm was generated for a 120 m × 30 m area covering the entire wreck site using geographical coordination using 1,716 images of the wreck obtained during scuba expeditions.

The USS Emmons stalled from damages incurred during an attack by Japanese kamikaze planes on April 6, 1945. The ship was abandoned and intentionally sunk. The wreckage of the kamikaze planes is also scattered on the seafloor. More than 70 years after the end of the Second World War, documentation of the war through material evidence beyond first-person accounts is increasing in significance. The model provides a primary record of the current state of the wreck, and allows for the establishment of various measures for its conservation.