{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,3]],"date-time":"2026-06-03T12:30:15Z","timestamp":1780489815714,"version":"3.54.1"},"reference-count":29,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2022,12,30]],"date-time":"2022-12-30T00:00:00Z","timestamp":1672358400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Natural Science Foundation of China","award":["61364008"],"award-info":[{"award-number":["61364008"]}]},{"name":"National Natural Science Foundation of China","award":["202101AS070016"],"award-info":[{"award-number":["202101AS070016"]}]},{"name":"\u201cYunnan Talents Support Plan\u201d project of Yunnan","award":["61364008"],"award-info":[{"award-number":["61364008"]}]},{"name":"\u201cYunnan Talents Support Plan\u201d project of Yunnan","award":["202101AS070016"],"award-info":[{"award-number":["202101AS070016"]}]},{"name":"Key Projects of Yunnan Basic Research Plan","award":["61364008"],"award-info":[{"award-number":["61364008"]}]},{"name":"Key Projects of Yunnan Basic Research Plan","award":["202101AS070016"],"award-info":[{"award-number":["202101AS070016"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The variational optical flow model is used in this work to investigate a subgrid-scale optimization approach for modeling complex fluid flows in image sequences and estimating their two-dimensional velocity fields. To solve the problem of lack of sub-grid small-scale structure information in variational optical flow estimation, we combine the motion laws of incompressible fluids. Introducing the idea of large eddy simulation, the instantaneous motion can be decomposed into large-scale motion and a small-scale turbulence in the data term. The Smagorinsky model is used to model and solve the small-scale turbulence. The improved subgrid scale Horn\u2013Schunck (SGS-HS) optical flow algorithm provides better results in velocity field estimation of turbulent image sequences than the traditional Farneback dense optical flow algorithm. To make the SGS-HS algorithm equally competent for the open channel flow measurement task, a velocity gradient constraint is chosen for the canonical term of the model, which is used to improve the accuracy of the SGS-HS algorithm in velocimetric experiments in the case of the relatively uniform flow direction of the open channel flow field. The experimental results show that our algorithm has better performance in open channel velocimetry compared with the conventional algorithm.<\/jats:p>","DOI":"10.3390\/s23010437","type":"journal-article","created":{"date-parts":[[2023,1,2]],"date-time":"2023-01-02T03:08:59Z","timestamp":1672628939000},"page":"437","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":12,"title":["Subgrid Variational Optimized Optical Flow Estimation Algorithm for Image Velocimetry"],"prefix":"10.3390","volume":"23","author":[{"given":"Haoxuan","family":"Xu","sequence":"first","affiliation":[{"name":"Faculty of Information Engineering and Automation, Kunming University of Science and Technology, Kunming 650000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9659-0452","authenticated-orcid":false,"given":"Jianping","family":"Wang","sequence":"additional","affiliation":[{"name":"Faculty of Information Engineering and Automation, Kunming University of Science and Technology, Kunming 650000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ya","family":"Zhang","sequence":"additional","affiliation":[{"name":"Nanjing Institute of Water Resources and Hydrology Automation, Ministry of Water Resources, Nanjing 210000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Guo","family":"Zhang","sequence":"additional","affiliation":[{"name":"Faculty of Information Engineering and Automation, Kunming University of Science and Technology, Kunming 650000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhaolong","family":"Xiong","sequence":"additional","affiliation":[{"name":"Faculty of Information Engineering and Automation, Kunming University of Science and Technology, Kunming 650000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,12,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"261","DOI":"10.1146\/annurev.fl.23.010191.001401","article-title":"Particle-imaging techniques for experimental fluid mechanics","volume":"23","author":"Adrian","year":"1991","journal-title":"Annu. 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