{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,23]],"date-time":"2026-09-23T05:05:32Z","timestamp":1790139932144,"version":"4.0.1"},"reference-count":31,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2026,9,19]],"date-time":"2026-09-19T00:00:00Z","timestamp":1789776000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100011033","name":"Agencia Estatal de Investigaci\u00f3n","doi-asserted-by":"publisher","award":["PID2024-161576OB-I00"],"award-info":[{"award-number":["PID2024-161576OB-I00"]}],"id":[{"id":"10.13039\/501100011033","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100011033","name":"Agencia Estatal de Investigaci\u00f3n","doi-asserted-by":"publisher","award":["PLEC2023-010343"],"award-info":[{"award-number":["PLEC2023-010343"]}],"id":[{"id":"10.13039\/501100011033","id-type":"DOI","asserted-by":"publisher"}]},{"award":["PID2024-161576OB-I00"],"award-info":[{"award-number":["PID2024-161576OB-I00"]}],"id":[{"id":"https:\/\/ror.org\/003x0zc53","id-type":"ROR","asserted-by":"publisher"}]},{"award":["PLEC2023-010343"],"award-info":[{"award-number":["PLEC2023-010343"]}],"id":[{"id":"https:\/\/ror.org\/003x0zc53","id-type":"ROR","asserted-by":"publisher"}]},{"name":"European Regional Development Fund"},{"id":[{"id":"https:\/\/ror.org\/01rkhv978","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Railway wagon inspection is a key enabler of digital railway operations and intelligent asset management that requires a complete view of each wagon side, which a fixed trackside area-scan camera cannot capture in a single frame as the train passes. We present a complete image stitching pipeline that reconstructs each wagon from its sequence of overlapping frames under uncontrolled outdoor conditions: day and night illumination, varied wagon surfaces, background clutter and camera vibration. The pipeline applies seven sequential keypoint filters to dense correspondences produced by a learned dense matcher, followed by robust median displacement estimation and a sequence-level outlier recovery mechanism. We also propose a three-tier evaluation framework that scores a stitching system from its reported geometry alone, without access to its internals, supported by a benchmark dataset of 30 railway wagons across six trains with 262 manually annotated frame pairs. End-to-end evaluation on the benchmark dataset shows that the pipeline recovers accurate displacements where the raw correspondences yield none; no single filter dominates on every measure, with the decisive filter depending on the surface; and the complete system outperforms both a classical sparse-feature baseline and a generic dense-matching baseline. The evaluation framework is publicly released, and the annotated dataset is available on request, to facilitate reproducibility.<\/jats:p>","DOI":"10.3390\/s26185917","type":"journal-article","created":{"date-parts":[[2026,9,22]],"date-time":"2026-09-22T09:04:17Z","timestamp":1790067857000},"page":"5917","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Robust Image Stitching for Railway Wagon Inspection in Uncontrolled Outdoor Environments"],"prefix":"10.3390","volume":"26","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7232-3197","authenticated-orcid":false,"given":"Alejandro","family":"Diaz-Diaz","sequence":"first","affiliation":[{"name":"Transportation Department, Indra Company, San Fernando de Henares, 28830 Madrid, Spain"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"software","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2538-9580","authenticated-orcid":false,"given":"Francisco","family":"Parrilla","sequence":"additional","affiliation":[{"name":"Transportation Department, Indra Company, San Fernando de Henares, 28830 Madrid, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0087-3077","authenticated-orcid":false,"given":"Luis M.","family":"Bergasa","sequence":"additional","affiliation":[{"name":"Departamento de Electr\u00f3nica, Universidad de Alcal\u00e1 (UAH), Alcal\u00e1 de Henares, 28801 Madrid, Spain"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"resources","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"},{"role":"project-administration","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,19]]},"reference":[{"key":"ref_1","unstructured":"Europe\u2019s Rail Joint Undertaking (2022). 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