{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,18]],"date-time":"2026-03-18T19:19:57Z","timestamp":1773861597054,"version":"3.50.1"},"reference-count":37,"publisher":"MDPI AG","issue":"23","license":[{"start":{"date-parts":[[2019,11,24]],"date-time":"2019-11-24T00:00:00Z","timestamp":1574553600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Key research and development program of Ministry of science and technology","award":["2016YFB0500801"],"award-info":[{"award-number":["2016YFB0500801"]}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["91538106; 41501503;41601490; 41501383"],"award-info":[{"award-number":["91538106; 41501503;41601490; 41501383"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100002858","name":"China Postdoctoral Science Foundation","doi-asserted-by":"publisher","award":["2015M582276"],"award-info":[{"award-number":["2015M582276"]}],"id":[{"id":"10.13039\/501100002858","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Hubei Provincial Natural Science Foundation of China","award":["2015CFB330"],"award-info":[{"award-number":["2015CFB330"]}]},{"name":"Open Research Fund of State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing","award":["15E02"],"award-info":[{"award-number":["15E02"]}]},{"name":"Open Research Fund of State Key Laboratory of Geo-information Engineering","award":["SKLGIE2015-Z-3-1"],"award-info":[{"award-number":["SKLGIE2015-Z-3-1"]}]},{"name":"Fundamental Research Funds for the Central University","award":["2042016kf0163"],"award-info":[{"award-number":["2042016kf0163"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>To effectively balance speckle smoothing and preservation of edges and radiation, a novel anisotropic diffusion filter was developed that uses a directional coherent coefficient. The proposed filter effectively improves the edge detection operator of a traditional anisotropic diffusion filter. The new edge detection operator calculates 16 direction coherence coefficients to avoid the interference of the edge direction. For the diffusion function, the proposed method directly uses the detected directional coherent edge as the diffusion coefficient, which simplifies the calculation of the diffusion function and avoids the adverse effects of inaccurate estimation of the diffusion function threshold for a traditional anisotropic diffusion filter. The influence of the number of iterations and time steps on the proposed filter was analyzed. A series of experiments was conducted with a simulated image and three real synthetic-aperture radar images from different sensors. The results confirmed that the proposed method not only significantly reduces speckle but also effectively preserves the edge and radiation information of images.<\/jats:p>","DOI":"10.3390\/rs11232768","type":"journal-article","created":{"date-parts":[[2019,11,25]],"date-time":"2019-11-25T03:10:00Z","timestamp":1574651400000},"page":"2768","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Speckle Reduction by Directional Coherent Anisotropic Diffusion"],"prefix":"10.3390","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3987-5336","authenticated-orcid":false,"given":"Guo","family":"Zhang","sequence":"first","affiliation":[{"name":"State Key Laboratory of Information Engineering in Surveying Mapping and Remote Sensing, Wuhan University, Wuhan 430079, China"},{"name":"Collaborative Innovation Center of Geospatial Technology, Wuhan University, Wuhan 430079, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4547-5507","authenticated-orcid":false,"given":"Fengcheng","family":"Guo","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Information Engineering in Surveying Mapping and Remote Sensing, Wuhan University, Wuhan 430079, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5285-5738","authenticated-orcid":false,"given":"Qingjun","family":"Zhang","sequence":"additional","affiliation":[{"name":"Collaborative Innovation Center of Geospatial Technology, Wuhan University, Wuhan 430079, China"},{"name":"China Academy of Space Technology, Beijing 100094, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6310-2977","authenticated-orcid":false,"given":"Kai","family":"Xu","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Information Engineering in Surveying Mapping and Remote Sensing, Wuhan University, Wuhan 430079, China"}]},{"given":"Peng","family":"Jia","sequence":"additional","affiliation":[{"name":"China Satellite Navigation Office, Beijing 100034, China"}]},{"given":"Xiaoyun","family":"Hao","sequence":"additional","affiliation":[{"name":"Shandong Aerospace Electro-Technology Institute, Yantai 264000, China"}]}],"member":"1968","published-online":{"date-parts":[[2019,11,24]]},"reference":[{"key":"ref_1","unstructured":"Oliver, C., and Quegan, S. 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