{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,10]],"date-time":"2026-04-10T12:45:41Z","timestamp":1775825141068,"version":"3.50.1"},"reference-count":29,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2024,1,3]],"date-time":"2024-01-03T00:00:00Z","timestamp":1704240000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["62173031"],"award-info":[{"award-number":["62173031"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["2021KJ066"],"award-info":[{"award-number":["2021KJ066"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["FRF-IDRY-22-029"],"award-info":[{"award-number":["FRF-IDRY-22-029"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Tianjin Education Commission Scientific Research Program Project","award":["62173031"],"award-info":[{"award-number":["62173031"]}]},{"name":"Tianjin Education Commission Scientific Research Program Project","award":["2021KJ066"],"award-info":[{"award-number":["2021KJ066"]}]},{"name":"Tianjin Education Commission Scientific Research Program Project","award":["FRF-IDRY-22-029"],"award-info":[{"award-number":["FRF-IDRY-22-029"]}]},{"name":"Interdisciplinary Research Project for Young Teachers of USTB (Fundamental Research Funds for the Central Universities)","award":["62173031"],"award-info":[{"award-number":["62173031"]}]},{"name":"Interdisciplinary Research Project for Young Teachers of USTB (Fundamental Research Funds for the Central Universities)","award":["2021KJ066"],"award-info":[{"award-number":["2021KJ066"]}]},{"name":"Interdisciplinary Research Project for Young Teachers of USTB (Fundamental Research Funds for the Central Universities)","award":["FRF-IDRY-22-029"],"award-info":[{"award-number":["FRF-IDRY-22-029"]}]},{"name":"Beijing Top Discipline for Artificial Intelligent Science and Engineering, University of Science and Technology Beijing","award":["62173031"],"award-info":[{"award-number":["62173031"]}]},{"name":"Beijing Top Discipline for Artificial Intelligent Science and Engineering, University of Science and Technology Beijing","award":["2021KJ066"],"award-info":[{"award-number":["2021KJ066"]}]},{"name":"Beijing Top Discipline for Artificial Intelligent Science and Engineering, University of Science and Technology Beijing","award":["FRF-IDRY-22-029"],"award-info":[{"award-number":["FRF-IDRY-22-029"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Three-dimensional (3D) localization plays an important role in visual sensor networks. However, the frame rate and flexibility of the existing vision-based localization systems are limited by using synchronized multiple cameras. For such a purpose, this paper focuses on developing an indoor 3D localization system based on unsynchronized multiple cameras. First of all, we propose a calibration method for unsynchronized perspective\/fish-eye cameras based on timestamp matching and pixel fitting by using a wand under general motions. With the multi-camera calibration result, we then designed a localization method for the unsynchronized multi-camera system based on the extended Kalman filter (EKF). Finally, extensive experiments were conducted to demonstrate the effectiveness of the established 3D localization system. The obtained results provided valuable insights into the camera calibration and 3D localization of unsynchronized multiple cameras in visual sensor networks.<\/jats:p>","DOI":"10.3390\/s24010284","type":"journal-article","created":{"date-parts":[[2024,1,3]],"date-time":"2024-01-03T05:50:38Z","timestamp":1704261038000},"page":"284","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Wand-Based Calibration of Unsynchronized Multiple Cameras for 3D Localization"],"prefix":"10.3390","volume":"24","author":[{"given":"Sujie","family":"Zhang","sequence":"first","affiliation":[{"name":"Tianjin College, University of Science and Technology Beijing, Tianjin 301830, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Qiang","family":"Fu","sequence":"additional","affiliation":[{"name":"School of Intelligence Science and Technology, University of Science and Technology Beijing, Beijing 100083, China"},{"name":"Institute of Artificial Intelligence, University of Science and Technology Beijing, Beijing 100083, China"},{"name":"Key Laboratory of Intelligent Bionic Unmanned Systems, Ministry of Education, University of Science and Technology Beijing, Beijing 100083, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2024,1,3]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"3434","DOI":"10.1109\/LRA.2018.2852843","article-title":"Rt3d: Real-time 3-d vehicle detection in lidar point cloud for autonomous driving","volume":"3","author":"Zeng","year":"2018","journal-title":"IEEE Robot. Autom. Lett."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"3139","DOI":"10.1109\/TIM.2019.2928615","article-title":"Indoor multi-camera-based testbed for 3-D tracking and control of UAVs","volume":"69","author":"Deng","year":"2019","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"45","DOI":"10.1109\/MNET.2004.1316761","article-title":"Time synchronization in sensor networks: A survey","volume":"18","author":"Sivrikaya","year":"2004","journal-title":"IEEE Netw."},{"key":"ref_4","first-page":"1","article-title":"Adaptive recursive decentralized cooperative localization for multirobot systems with time-varying measurement accuracy","volume":"70","author":"Huang","year":"2021","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"101","DOI":"10.1007\/s11263-010-0411-1","article-title":"Calibration of central catadioptric cameras using a DLT-like approach","volume":"93","author":"Puig","year":"2011","journal-title":"Int. J. Comput. Vis."},{"key":"ref_6","unstructured":"Du, B., and Zhu, H. (2011, January 15\u201317). Estimating fisheye camera parameters using one single image of 3D pattern. Proceedings of the 2011 International Conference on Electric Information and Control Engineering, Wuhan, China."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Song, L., Wu, W., Guo, J., and Li, X. (2013, January 26\u201327). Survey on camera calibration technique. Proceedings of the 2013 5th International Conference on Intelligent Human-Machine Systems and Cybernetics, Hangzhou, China.","DOI":"10.1109\/IHMSC.2013.240"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Mei, C., and Rives, P. (2007, January 10\u201314). Single view point omnidirectional camera calibration from planar grids. Proceedings of the 2007 IEEE International Conference on Robotics and Automation, Rome, Italy.","DOI":"10.1109\/ROBOT.2007.364084"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"3257","DOI":"10.1109\/JSEN.2019.2958104","article-title":"Accurate and flexible calibration method for a class of visual sensor networks","volume":"20","author":"Deng","year":"2019","journal-title":"IEEE Sens. J."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Zhou, T., Cheng, X., Lin, P., Wu, Z., and Liu, E. (2020). A general point-based method for self-calibration of terrestrial laser scanners considering stochastic information. Remote Sens., 12.","DOI":"10.3390\/rs12182923"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Faugeras, O.D., Luong, Q.T., and Maybank, S.J. (1992, January 19\u201322). Camera self-calibration: Theory and experiments. Proceedings of the Second European Conference on Computer Vision, Santa Margherita Ligure, Italy.","DOI":"10.1007\/3-540-55426-2_37"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"123","DOI":"10.1007\/BF00127171","article-title":"A theory of self-calibration of a moving camera","volume":"8","author":"Maybank","year":"1992","journal-title":"Int. J. Comput. Vis."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"5","DOI":"10.1023\/A:1007957826135","article-title":"Self-calibration of stationary cameras","volume":"22","author":"Hartley","year":"1997","journal-title":"Int. J. Comput. Vis."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"114","DOI":"10.1109\/70.481755","article-title":"A self-calibration technique for active vision systems","volume":"12","author":"Sang","year":"1996","journal-title":"IEEE Trans. Robot. Autom."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Kwon, H., Park, J., and Kak, A.C. (2007, January 10\u201314). A new approach for active stereo camera calibration. Proceedings of the 2007 IEEE International Conference on Robotics and Automation, Rome, Italy.","DOI":"10.1109\/ROBOT.2007.363963"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Khan, A., Aragon-Camarasa, G., Sun, L., and Siebert, J.P. (2016, January 3\u20137). On the calibration of active binocular and RGBD vision systems for dual-arm robots. Proceedings of the 2016 IEEE International Conference on Robotics and Biomimetics (ROBIO), Qingdao, China.","DOI":"10.1109\/ROBIO.2016.7866616"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"892","DOI":"10.1109\/TPAMI.2004.21","article-title":"Camera calibration with one-dimensional objects","volume":"26","author":"Zhang","year":"2004","journal-title":"IEEE Trans. Pattern Anal. Mach. Intell."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"395","DOI":"10.1007\/s00138-008-0122-6","article-title":"Frame-level temporal calibration of video sequences from unsynchronized cameras","volume":"19","author":"Velipasalar","year":"2008","journal-title":"Mach. Vis. Appl."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Noguchi, M., and Kato, T. (2007, January 21\u201322). Geometric and timing calibration for unsynchronized cameras using trajectories of a moving marker. Proceedings of the 2007 IEEE Workshop on Applications of Computer Vision (WACV\u201907), Austin, TX, USA.","DOI":"10.1109\/WACV.2007.27"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Matsumoto, H., Sato, J., and Sakaue, F. (2010, January 13\u201318). Multiview constraints in frequency space and camera calibration from unsynchronized images. Proceedings of the 2010 IEEE Computer Society Conference on Computer Vision and Pattern Recognition, San Francisco, CA, USA.","DOI":"10.1109\/CVPR.2010.5539779"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"25292","DOI":"10.1364\/OE.20.025292","article-title":"Convenient calibration method for unsynchronized camera networks using an inaccurate small reference object","volume":"20","author":"Kim","year":"2012","journal-title":"Opt. Express"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"545","DOI":"10.1007\/s00138-016-0765-7","article-title":"Achieving invariance to the temporal offset of unsynchronized cameras through epipolar point-line triangulation","volume":"27","author":"Benrhaiem","year":"2016","journal-title":"Mach. Vis. Appl."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Piao, Y., and Sato, J. (2007, January 10\u201314). Computing epipolar geometry from unsynchronized cameras. Proceedings of the 14th International Conference on Image Analysis and Processing (ICIAP 2007), Modena, Italy.","DOI":"10.1109\/ICIAP.2007.4362823"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1335","DOI":"10.1109\/TPAMI.2006.153","article-title":"A generic camera model and calibration method for conventional, wide-angle, and fish-eye lenses","volume":"28","author":"Kannala","year":"2006","journal-title":"IEEE Trans. Pattern Anal. Mach. Intell."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"378","DOI":"10.1049\/iet-cvi.2014.0181","article-title":"Calibration of multiple fish-eye cameras using a wand","volume":"9","author":"Fu","year":"2015","journal-title":"IET Comput. Vis."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"756","DOI":"10.1109\/TPAMI.2004.17","article-title":"An efficient solution to the five-point relative pose problem","volume":"26","author":"Nister","year":"2004","journal-title":"IEEE Trans. Pattern Anal. Mach. Intell."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Hartley, R., and Zisserman, A. (2004). Multiple View Geometry in Computer Vision, Cambridge University Press.","DOI":"10.1017\/CBO9780511811685"},{"key":"ref_28","unstructured":"Lourakis, M.I.A. (2010, January 5\u201311). Computing epipolar geometry from unsynchronized cameras. Proceedings of the 11th European Conference on Computer Vision, Heraklion, Crete, Greece."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"41814","DOI":"10.1109\/ACCESS.2020.2976733","article-title":"A robust pose estimation method for multicopters using off-board multiple cameras","volume":"8","author":"Fu","year":"2020","journal-title":"IEEE Access"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/24\/1\/284\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T13:38:55Z","timestamp":1760103535000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/24\/1\/284"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,1,3]]},"references-count":29,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2024,1]]}},"alternative-id":["s24010284"],"URL":"https:\/\/doi.org\/10.3390\/s24010284","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,1,3]]}}}