{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T23:42:12Z","timestamp":1760139732239,"version":"build-2065373602"},"reference-count":30,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2022,4,21]],"date-time":"2022-04-21T00:00:00Z","timestamp":1650499200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100002241","name":"Japan Science and Technology Agency","doi-asserted-by":"publisher","award":["JPMJCR1761"],"award-info":[{"award-number":["JPMJCR1761"]}],"id":[{"id":"10.13039\/501100002241","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Earthquake Research Institute, the University of Tokyo","award":["2021\u2010B\u201001"],"award-info":[{"award-number":["2021\u2010B\u201001"]}]},{"DOI":"10.13039\/501100001691","name":"Japan Society for the Promotion of Science","doi-asserted-by":"publisher","award":["JP21H04750"],"award-info":[{"award-number":["JP21H04750"]}],"id":[{"id":"10.13039\/501100001691","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The comprehensive production of detailed bathymetric maps is important for disaster prevention, resource exploration, safe navigation, marine salvage, and monitoring of marine organisms. However, owing to observation difficulties, the amount of data on the world\u2019s seabed topography is scarce. Therefore, it is essential to develop methods that effectively use the limited data. In this study, based on dictionary learning and sparse coding, we modified the super-resolution technique and applied it to seafloor topographical maps. Improving on the conventional method, before dictionary learning, we performed pre-processing to separate the teacher image into a low-frequency component that has a general structure and a high-frequency component that captures the detailed topographical features. We learn the topographical features by training the dictionary. As a result, the root-mean-square error (RMSE) was reduced by 30% compared with bicubic interpolation and accuracy was improved, especially in the rugged part of the terrain. The proposed method, which learns a dictionary to capture topographical features and reconstructs them using a dictionary, produces super-resolution with high interpretability.<\/jats:p>","DOI":"10.3390\/s22093198","type":"journal-article","created":{"date-parts":[[2022,4,24]],"date-time":"2022-04-24T00:45:21Z","timestamp":1650761121000},"page":"3198","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Super-Resolution and Feature Extraction for Ocean Bathymetric Maps Using Sparse Coding"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7073-788X","authenticated-orcid":false,"given":"Taku","family":"Yutani","sequence":"first","affiliation":[{"name":"Research Institute for Marine Geodynamics (IMG), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka 237-0061, Japan"},{"name":"Research Institute for Value-Added-Information Generation (VAiG), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 3173-25 Showa-machi, Isogo-ku, Yokohama 236-0001, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Oak","family":"Yono","sequence":"additional","affiliation":[{"name":"Ocean High Technology Institute, Inc., 2-29-12 Honcho, Nakano-ku, Tokyo 164-0012, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7161-9458","authenticated-orcid":false,"given":"Tatsu","family":"Kuwatani","sequence":"additional","affiliation":[{"name":"Research Institute for Marine Geodynamics (IMG), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka 237-0061, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3306-5997","authenticated-orcid":false,"given":"Daisuke","family":"Matsuoka","sequence":"additional","affiliation":[{"name":"Research Institute for Value-Added-Information Generation (VAiG), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 3173-25 Showa-machi, Isogo-ku, Yokohama 236-0001, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Junji","family":"Kaneko","sequence":"additional","affiliation":[{"name":"Research Institute for Marine Resources Utilization, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka 237-0061, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mitsuko","family":"Hidaka","sequence":"additional","affiliation":[{"name":"Research Institute for Value-Added-Information Generation (VAiG), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 3173-25 Showa-machi, Isogo-ku, Yokohama 236-0001, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Takafumi","family":"Kasaya","sequence":"additional","affiliation":[{"name":"Research Institute for Marine Resources Utilization, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka 237-0061, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5627-1067","authenticated-orcid":false,"given":"Yukari","family":"Kido","sequence":"additional","affiliation":[{"name":"Institute for Marine-Earth Exploration and Engineering (MarE3), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka 237-0061, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yoichi","family":"Ishikawa","sequence":"additional","affiliation":[{"name":"Research Institute for Value-Added-Information Generation (VAiG), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 3173-25 Showa-machi, Isogo-ku, Yokohama 236-0001, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Toshiaki","family":"Ueki","sequence":"additional","affiliation":[{"name":"Ocean High Technology Institute, Inc., 2-29-12 Honcho, Nakano-ku, Tokyo 164-0012, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Eiichi","family":"Kikawa","sequence":"additional","affiliation":[{"name":"Research Institute for Value-Added-Information Generation (VAiG), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 3173-25 Showa-machi, Isogo-ku, Yokohama 236-0001, Japan"},{"name":"IDEA Consultants, Inc., 2-2-2 Hayabuchi, Tsuzuki-ku, Yokohama 224-0025, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,4,21]]},"reference":[{"unstructured":"(2022, February 10). 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