{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,27]],"date-time":"2026-05-27T17:43:46Z","timestamp":1779903826392,"version":"3.53.1"},"reference-count":50,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2015,1,12]],"date-time":"2015-01-12T00:00:00Z","timestamp":1421020800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>In this study we present a hyperspectral flying goniometer system, based on a rotary-wing unmanned aerial vehicle (UAV) equipped with a spectrometer mounted on an active gimbal. We show that this approach may be used to collect multiangular hyperspectral data over vegetated environments. The pointing and positioning accuracy are assessed using structure from motion and vary from \u03c3 = 1\u00b0 to 8\u00b0 in pointing and \u03c3 = 0.7 to 0.8 m in positioning. We use a wheat dataset to investigate the influence of angular effects on the NDVI, TCARI and REIP vegetation indices. Angular effects caused significant variations on the indices: NDVI = 0.83\u20130.95; TCARI = 0.04\u20130.116; REIP = 729\u2013735 nm. Our analysis highlights the necessity to consider angular effects in optical sensors when observing vegetation. We compare the measurements of the UAV goniometer to the angular modules of the SCOPE radiative transfer model. Model and measurements are in high accordance  (r2 = 0.88) in the infrared region at angles close to nadir; in contrast the comparison show discrepancies at low tilt angles (r2 = 0.25). This study demonstrates that the UAV goniometer is a promising approach for the fast and flexible assessment of angular effects.<\/jats:p>","DOI":"10.3390\/rs70100725","type":"journal-article","created":{"date-parts":[[2015,1,12]],"date-time":"2015-01-12T13:30:46Z","timestamp":1421069446000},"page":"725-746","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":121,"title":["Angular Dependency of Hyperspectral Measurements over Wheat Characterized by a Novel UAV Based Goniometer"],"prefix":"10.3390","volume":"7","author":[{"given":"Andreas","family":"Burkart","sequence":"first","affiliation":[{"name":"Research Center J\u00fclich, Institute of Bio- and Geosciences, IBG-2: Plant Sciences,  52428 J\u00fclich, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Helge","family":"Aasen","sequence":"additional","affiliation":[{"name":"Department of Geoscience, Working Group GIS and Remote Sensing, University of Cologne, 50923 Cologne, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Luis","family":"Alonso","sequence":"additional","affiliation":[{"name":"Laboratory of image processing, University of Valencia, 46980 Paterna, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gunter","family":"Menz","sequence":"additional","affiliation":[{"name":"Department of Geography, Remote Sensing Research Group, University of Bonn,  53001 Bonn, Germany"},{"name":"Center for Remote Sensing for Land Surfaces, University of Bonn, 53113 Bonn, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Georg","family":"Bareth","sequence":"additional","affiliation":[{"name":"Department of Geoscience, Working Group GIS and Remote Sensing, University of Cologne, 50923 Cologne, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9993-4588","authenticated-orcid":false,"given":"Uwe","family":"Rascher","sequence":"additional","affiliation":[{"name":"Research Center J\u00fclich, Institute of Bio- and Geosciences, IBG-2: Plant Sciences,  52428 J\u00fclich, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2015,1,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1807","DOI":"10.1080\/01431168708954818","article-title":"Review article principles of field spectroscopy","volume":"8","author":"Milton","year":"1987","journal-title":"Remote Sens."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Tian, Y., Dickinson, R.E., Zhou, L., Zeng, X., Dai, Y., Myneni, R.B., Knyazikhin, Y., Zhang, X., Friedl, M., and Yu, H. 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