{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,21]],"date-time":"2026-05-21T21:34:17Z","timestamp":1779399257230,"version":"3.53.1"},"reference-count":39,"publisher":"MDPI AG","issue":"21","license":[{"start":{"date-parts":[[2023,10,27]],"date-time":"2023-10-27T00:00:00Z","timestamp":1698364800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Natural Science Foundation of China","award":["41971427"],"award-info":[{"award-number":["41971427"]}]},{"name":"National Natural Science Foundation of China","award":["221100211000-5"],"award-info":[{"award-number":["221100211000-5"]}]},{"name":"National Natural Science Foundation of China","award":["222300420592"],"award-info":[{"award-number":["222300420592"]}]},{"name":"Program of Song Shan Laboratory","award":["41971427"],"award-info":[{"award-number":["41971427"]}]},{"name":"Program of Song Shan Laboratory","award":["221100211000-5"],"award-info":[{"award-number":["221100211000-5"]}]},{"name":"Program of Song Shan Laboratory","award":["222300420592"],"award-info":[{"award-number":["222300420592"]}]},{"name":"National Science Foundation of Henan Province","award":["41971427"],"award-info":[{"award-number":["41971427"]}]},{"name":"National Science Foundation of Henan Province","award":["221100211000-5"],"award-info":[{"award-number":["221100211000-5"]}]},{"name":"National Science Foundation of Henan Province","award":["222300420592"],"award-info":[{"award-number":["222300420592"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Laser altimetry data from the Ice, Cloud, and land Elevation Satellite-2 (ICESat-2) contain a lot of noise, which necessitates the requirement for a signal photon extraction method. In this study, we propose a density clustering method, which combines slope and elevation information from optical stereo images and adaptively adjusts the neighborhood search direction in the along-track direction. The local classification density threshold was calculated adaptively according to the uneven spatial distribution of noise and signal density, and reliable surface signal points were extracted. The performance of the algorithm was validated for strong and weak beam laser altimetry data using optical stereo images with different resolutions and positioning accuracies. The results were compared qualitatively and quantitatively with those obtained using the ATL08 algorithm. The signal extraction quality was better than that of the ATL08 algorithm for steep slope and low signal-to-noise ratio (SNR) regions. The proposed method can better balance the relationship between recall and precision, and its F1-score was higher than that of the ATL08 algorithm. The method can accurately extract continuous and reliable surface signals for both strong and weak beams among different terrains and land cover types.<\/jats:p>","DOI":"10.3390\/s23218752","type":"journal-article","created":{"date-parts":[[2023,10,27]],"date-time":"2023-10-27T11:50:18Z","timestamp":1698407418000},"page":"8752","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Signal Photon Extraction Method for ICESat-2 Data Using Slope and Elevation Information Provided by Stereo Images"],"prefix":"10.3390","volume":"23","author":[{"given":"Linyu","family":"Gu","sequence":"first","affiliation":[{"name":"Institute of Geospatial Information, PLA Strategic Support Force Information Engineering University, Zhengzhou 450001, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dazhao","family":"Fan","sequence":"additional","affiliation":[{"name":"Institute of Geospatial Information, PLA Strategic Support Force Information Engineering University, Zhengzhou 450001, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Song","family":"Ji","sequence":"additional","affiliation":[{"name":"Institute of Geospatial Information, PLA Strategic Support Force Information Engineering University, Zhengzhou 450001, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhihui","family":"Gong","sequence":"additional","affiliation":[{"name":"Institute of Geospatial Information, PLA Strategic Support Force Information Engineering University, Zhengzhou 450001, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dongzi","family":"Li","sequence":"additional","affiliation":[{"name":"Institute of Geospatial Information, PLA Strategic Support Force Information Engineering University, Zhengzhou 450001, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yang","family":"Dong","sequence":"additional","affiliation":[{"name":"Institute of Geospatial Information, PLA Strategic Support Force Information Engineering University, Zhengzhou 450001, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,10,27]]},"reference":[{"key":"ref_1","first-page":"1182","article-title":"The rigorous geometric model of satellite laser altimeter and preliminarily accuracy validation","volume":"45","author":"Tang","year":"2016","journal-title":"Acta Geod. 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