{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,21]],"date-time":"2026-02-21T12:13:00Z","timestamp":1771675980645,"version":"3.50.1"},"reference-count":42,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2022,5,7]],"date-time":"2022-05-07T00:00:00Z","timestamp":1651881600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Natural Science Foundation of China","award":["62101041"],"award-info":[{"award-number":["62101041"]}]},{"name":"National Natural Science Foundation of China","award":["T2012122"],"award-info":[{"award-number":["T2012122"]}]},{"name":"National Natural Science Foundation of China","award":["Z141101001514005"],"award-info":[{"award-number":["Z141101001514005"]}]},{"name":"Chang Jiang Scholars Program","award":["62101041"],"award-info":[{"award-number":["62101041"]}]},{"name":"Chang Jiang Scholars Program","award":["T2012122"],"award-info":[{"award-number":["T2012122"]}]},{"name":"Chang Jiang Scholars Program","award":["Z141101001514005"],"award-info":[{"award-number":["Z141101001514005"]}]},{"name":"Hundred Leading Talent Project of Beijing Science and Technology","award":["62101041"],"award-info":[{"award-number":["62101041"]}]},{"name":"Hundred Leading Talent Project of Beijing Science and Technology","award":["T2012122"],"award-info":[{"award-number":["T2012122"]}]},{"name":"Hundred Leading Talent Project of Beijing Science and Technology","award":["Z141101001514005"],"award-info":[{"award-number":["Z141101001514005"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Recently, ship detection in synthetic aperture radar (SAR) images has received extensive attention. Most of the current ship detectors preset dense anchor boxes to achieve spatial alignment with ground-truth (GT) objects. Then, the detector defines the positive and negative samples based on the intersection-over-unit (IoU) between the anchors and GT objects. However, this label assignment strategy confuses the learning process of the model to a certain extent and results in suboptimal classification and regression results. In this paper, an adaptive sample assignment (ASA) strategy is proposed to select high-quality positive samples according to the spatial alignment and the knowledge learned from the regression and classification branches. Using our model, the selection of positive and negative samples is more explicit, which achieves better detection performance. A regression guided loss is proposed to further lead the detector to select well-classified and well-regressed anchors as high-quality positive samples by introducing the regression performance as a soft label in the calculation of the classification loss. In order to alleviate false alarms, a feature aggregation enhancement pyramid network (FAEPN) is proposed to enhance multi-scale feature representations and suppress the interference of background noise. Extensive experiments using the SAR ship detection dataset (SSDD) and high-resolution SAR images dataset (HRSID) demonstrate the superiority of our proposed approach.<\/jats:p>","DOI":"10.3390\/rs14092238","type":"journal-article","created":{"date-parts":[[2022,5,8]],"date-time":"2022-05-08T23:27:25Z","timestamp":1652052445000},"page":"2238","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":31,"title":["An Adaptive Sample Assignment Strategy Based on Feature Enhancement for Ship Detection in SAR Images"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2013-6592","authenticated-orcid":false,"given":"Hao","family":"Shi","sequence":"first","affiliation":[{"name":"Radar Research Lab, School of Information and Electronics, Beijing Institute of Technology, Beijing 100081, China"},{"name":"Chongqing Innovation Center, Beijing Institute of Techonology, Chongqing 401120, China"}]},{"given":"Zhonghao","family":"Fang","sequence":"additional","affiliation":[{"name":"Radar Research Lab, School of Information and Electronics, Beijing Institute of Technology, Beijing 100081, China"}]},{"given":"Yupei","family":"Wang","sequence":"additional","affiliation":[{"name":"Radar Research Lab, School of Information and Electronics, Beijing Institute of Technology, Beijing 100081, China"},{"name":"Chongqing Innovation Center, Beijing Institute of Techonology, Chongqing 401120, China"}]},{"given":"Liang","family":"Chen","sequence":"additional","affiliation":[{"name":"Radar Research Lab, School of Information and Electronics, Beijing Institute of Technology, Beijing 100081, China"},{"name":"Chongqing Innovation Center, Beijing Institute of Techonology, Chongqing 401120, China"}]}],"member":"1968","published-online":{"date-parts":[[2022,5,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Habibollahi, R., Seydi, S.T., Hasanlou, M., and Mahdianpari, M. 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