{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,19]],"date-time":"2026-02-19T04:09:56Z","timestamp":1771474196869,"version":"3.50.1"},"reference-count":35,"publisher":"MDPI AG","issue":"22","license":[{"start":{"date-parts":[[2021,11,19]],"date-time":"2021-11-19T00:00:00Z","timestamp":1637280000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100000266","name":"Engineering and Physical Sciences Research Council","doi-asserted-by":"publisher","award":["S513908\/1"],"award-info":[{"award-number":["S513908\/1"]}],"id":[{"id":"10.13039\/501100000266","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Robotised Non-Destructive Testing (NDT) has revolutionised the field, increasing the speed of repetitive scanning procedures and ability to reach hazardous environments. Application of robot-assisted NDT within specific industries such as remanufacturing and Aersopace, in which parts are regularly moulded and susceptible to non-critical deformation has however presented drawbacks. In these cases, digital models for robotic path planning are not always available or accurate. Cutting edge methods to counter the limited flexibility of robots require an initial pre-scan using camera-based systems in order to build a CAD model for path planning. This paper has sought to create a novel algorithm that enables robot-assisted ultrasonic testing of unknown surfaces within a single pass. Key to the impact of this article is the enabled autonomous profiling with sensors whose aperture is several orders of magnitude smaller than the target surface, for surfaces of any scale. Potential applications of the algorithm presented include autonomous drone and crawler inspections of large, complex, unknown environments in addition to situations where traditional metrological profiling equipment is not practical, such as in confined spaces. In simulation, the proposed algorithm has completely mapped significantly curved and complex shapes by utilising only local information, outputting a traditional raster pattern when curvature is present only in a single direction. In practical demonstrations, both curved and non-simple surfaces were fully mapped with no required operator intervention. The core limitations of the algorithm in practical cases is the effective range of the applied sensor, and as a stand-alone method it lacks the required knowledge of the environment to prevent collisions. However, since the approach has met success in fully scanning non-obstructive but still significantly complex surfaces, the objectives of this paper have been met. Future work will focus on low-accuracy environmental sensing capabilities to tackle the challenges faced. The method has been designed to allow single-pass scans for Conformable Wedge Probe UT scanning, but may be applied to any surface scans in the case the sensor aperture is significantly smaller than the part.<\/jats:p>","DOI":"10.3390\/s21227692","type":"journal-article","created":{"date-parts":[[2021,11,19]],"date-time":"2021-11-19T08:29:17Z","timestamp":1637310557000},"page":"7692","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["A Novel Complete-Surface-Finding Algorithm for Online Surface Scanning with Limited View Sensors"],"prefix":"10.3390","volume":"21","author":[{"given":"Alastair","family":"Poole","sequence":"first","affiliation":[{"name":"Centre of Ultrasonic Engineering (CUE), University of Strathclyde, Glasgow G1 1XW, UK"},{"name":"The Welding Institute (TWI) Wales, Port Talbot SA13 1SB, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mark","family":"Sutcliffe","sequence":"additional","affiliation":[{"name":"The Welding Institute (TWI) Wales, Port Talbot SA13 1SB, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Gareth","family":"Pierce","sequence":"additional","affiliation":[{"name":"Centre of Ultrasonic Engineering (CUE), University of Strathclyde, Glasgow G1 1XW, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Anthony","family":"Gachagan","sequence":"additional","affiliation":[{"name":"Centre of Ultrasonic Engineering (CUE), University of Strathclyde, Glasgow G1 1XW, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,11,19]]},"reference":[{"key":"ref_1","unstructured":"Callieri, M., Fasano, A., Impoco, G., Cignoni, P., Scopigno, R., Parrini, G., and Biagini, G. (2004, January 6\u20139). RoboScan: An automatic system for accurate and unattended 3D scanning. Proceedings of the 2nd International Symposium on 3D Data Processing, Visualization and Transmission, Thessaloniki, Greece."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"611","DOI":"10.1007\/s11554-013-0386-6","article-title":"Efficient next-best-scan planning for autonomous 3D surface reconstruction of unknown objects","volume":"10","author":"Kriegel","year":"2013","journal-title":"J. Real-Time Image Process."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Giuliani, M., Assaf, T., and Giannaccini, M.E. (2018). SPGS: A New Method for Autonomous 3D Reconstruction of Unknown Objects by an Industrial Robot. Towards Autonomous Robotic Systems, Springer International Publishing.","DOI":"10.1007\/978-3-319-96728-8"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Almadhoun, R., Abduldayem, A., Taha, T., Seneviratne, L., and Zweiri, Y. (2019). Guided Next Best View for 3D Reconstruction of Large Complex Structures. Remote Sens., 11.","DOI":"10.3390\/rs11202440"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1007\/s13243-020-00091-x","article-title":"Vision guided robotic inspection for parts in manufacturing and remanufacturing industry","volume":"11","author":"Khan","year":"2021","journal-title":"J. Remanuf."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Kop\u00e1\u010dik, A., Erd\u00e9lyi, J., and Kyrinovi\u010d, P. (2020). Coordinate Measuring Systems and Machines. Engineering Surveys for Industry, Springer International Publishing.","DOI":"10.1007\/978-3-030-48309-8"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"216","DOI":"10.1016\/j.procir.2013.08.034","article-title":"An Adaptive Sampling Approach for Digitizing Unknown Free-form Surfaces based on Advanced Path Detecting","volume":"10","author":"Lu","year":"2013","journal-title":"Procedia CIRP"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"903624","DOI":"10.1155\/2015\/903624","article-title":"Reverse Engineering of Free-Form Surface Based on the Closed-Loop Theory","volume":"2015","author":"He","year":"2015","journal-title":"Sci. World J."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"108867","DOI":"10.1016\/j.measurement.2020.108867","article-title":"Profile tracking for multi-axis ultrasonic inspection of model-unknown free-form surfaces based on energy concentration","volume":"172","author":"Zhang","year":"2021","journal-title":"Measurement"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.cad.2016.03.003","article-title":"Sweep scan path planning for efficient freeform surface inspection on five-axis CMM","volume":"77","author":"Zhou","year":"2016","journal-title":"Comput.-Aided Des."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Guo, D., Jiang, G., Wu, Y., and Cheng, J. (2017). Automatic Ultrasonic Testing for Components with Complex Surfaces. DEStech Transactions on Engineering and Technology Research, DEStech Publishing Inc.","DOI":"10.12783\/dtetr\/mime2016\/10233"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"284","DOI":"10.1016\/j.measurement.2018.02.020","article-title":"Off-line scan path planning for robotic NDT","volume":"122","author":"Morozov","year":"2018","journal-title":"Measurement"},{"key":"ref_13","unstructured":"(2021, March 19). MS Windows Developer FloodFill Function. Available online: https:\/\/docs.microsoft.com\/en-us\/windows\/win32\/api\/wingdi\/nf-wingdi-floodfill."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Bhargava, N., Trivedi, P., Toshniwal, A., and Swarnkar, H. (2013, January 18\u201319). Iterative Region Merging and Object Retrieval Method Using Mean Shift Segmentation and Flood Fill Algorithm. Proceedings of the 2013 Third International Conference on Advances in Computing and Communications, Mumbai, India.","DOI":"10.1109\/ICACC.2013.100"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Chu, P., Cho, S., Park, Y., and Cho, K. (2017, January 16\u201318). Fast point cloud segmentation based on flood-fill algorithm. Proceedings of the 2017 IEEE International Conference on Multisensor Fusion and Integration for Intelligent Systems (MFI), Daegu, Korea.","DOI":"10.1109\/MFI.2017.8170397"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Lee, T., Lim, S., Lee, S., An, S., and Oh, S. (2012, January 7\u201312). Indoor mapping using planes extracted from noisy RGB-D sensors. Proceedings of the 2012 IEEE\/RSJ International Conference on Intelligent Robots and Systems, Vilamoura, Algarve, Portugal.","DOI":"10.1109\/IROS.2012.6385909"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"He, Y., Hu, T., and Zeng, D. (2019). Scan-flood Fill(SCAFF): An Efficient Automatic Precise Region Filling Algorithm for Complicated Regions. arXiv.","DOI":"10.1109\/CVPRW.2019.00104"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Chen, K., Xi, J., and Yu, Y. (2012, January 16\u201321). Fast quality-guided phase unwrapping algorithm for 3D profilometry based on object image edge detection. Proceedings of the 2012 IEEE Computer Society Conference on Computer Vision and Pattern Recognition Workshops, Providence, RI, USA.","DOI":"10.1109\/CVPRW.2012.6239239"},{"key":"ref_19","first-page":"450","article-title":"Comparison of phase unwrapping algorithms for topography reconstruction based on digital speckle pattern interferometry","volume":"Volume 10461","author":"Yu","year":"2017","journal-title":"AOPC 2017: Optical Spectroscopy and Imaging"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"012182","DOI":"10.1088\/1742-6596\/1069\/1\/012182","article-title":"A New Fast Quality-Guided Flood-Fill Phase Unwrapping Algorithm","volume":"1069","author":"Li","year":"2018","journal-title":"J. Phys. Conf. Ser."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Chen, K., Xi, J., Yu, Y., and Chicharo, J. (2010). Fast quality-guided flood-fill phase unwrapping algorithm for three-dimensional fringe pattern profilometry. SPIE\/COS Photonics Asia, SPIE.","DOI":"10.1117\/12.870232"},{"key":"ref_22","unstructured":"Ropiak, K., Polkowski, L., and Artiemjew, P. (2019). Rough Mereology Based CFill Algorithm for Robotic Path Planning (short paper). Proceedings of the 28th International Workshop on Concurrency, Specification and Programming, Olsztyn, Poland, 24\u201326 September 2019, University of Warmia and Mazury. CEUR Workshop Proceedings; CEUR-WS.org."},{"key":"ref_23","first-page":"8","article-title":"Design and Implementation of a Robot for Maze-Solving using Flood-Fill Algorithm","volume":"56","author":"Elshamarka","year":"2012","journal-title":"Int. J. Comput. Appl."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Kibler, S., and Raskovic, D. (2012, January 11\u201313). Coordinated multi-robot exploration of a building for search and rescue situations. Proceedings of the 2012 44th Southeastern Symposium on System Theory (SSST), Jacksonville, FL, USA.","DOI":"10.1109\/SSST.2012.6195147"},{"key":"ref_25","first-page":"180","article-title":"Design and Implementation of a Path Finding Robot Using Flood Fill Algorithm","volume":"5","author":"Tjiharjadi","year":"2016","journal-title":"Int. J. Mech. Eng. Robot. Res."},{"key":"ref_26","first-page":"366","article-title":"Optimization Maze Robot Using A* and Flood Fill Algorithm","volume":"6","author":"Tjiharjadi","year":"2017","journal-title":"Int. J. Mech. Eng. Robot. Res."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Ranade, S., and Manivannan, P.V. (March, January 28). Quadcopter Obstacle Avoidance and Path Planning Using Flood Fill Method. Proceedings of the 2019 2nd International Conference on Intelligent Autonomous Systems (ICoIAS), Singapore, Singapore.","DOI":"10.1109\/ICoIAS.2019.00036"},{"key":"ref_28","unstructured":"Kalisiak, M., and van de Panne, M. (2006, January 15\u201319). RRT-blossom: RRT with a local flood-fill behavior. Proceedings of the ICRA 2006 IEEE International Conference on Robotics and Automation, Orlando, FL, USA."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1877","DOI":"10.4028\/www.scientific.net\/AMM.284-287.1877","article-title":"Motion Planning of Multiple Pattern Formation for Mobile Robots","volume":"284\u2013287","author":"Guo","year":"2013","journal-title":"Appl. Mech. Mater."},{"key":"ref_30","unstructured":"Cheney, W., and Kincaid, D. (2012). Linear Algebra: Theory and Applications, Jones & Bartlett Learning. G\u2014Reference, Information and Interdisciplinary Subjects Series."},{"key":"ref_31","unstructured":"Meagher, D. (1982). Octree Generation: Analysis and Manipulation, Defense Technical Information Center."},{"key":"ref_32","unstructured":"Chase, H. (2021, September 01). Fundamental Forms of Surfaces and the Gauss-Bonnet Theorem. Available online: https:\/\/math.uchicago.edu\/~may\/REU2012\/REUPapers\/Chase.pdf."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"24","DOI":"10.1016\/j.cagd.2017.09.002","article-title":"A discrete surface theory","volume":"58","author":"Kotani","year":"2017","journal-title":"Comput. Aided Geom. Des."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"301","DOI":"10.1109\/70.938387","article-title":"Singularity analysis of a class of composite serial in-parallel robots","volume":"17","author":"Simaan","year":"2001","journal-title":"IEEE Trans. Robot. Autom."},{"key":"ref_35","unstructured":"(2021, March 19). Simon Perreault\u2019s C++ Octree Implementation. Available online: https:\/\/nomis80.org\/code\/octree.html."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/21\/22\/7692\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T07:32:43Z","timestamp":1760167963000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/21\/22\/7692"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,11,19]]},"references-count":35,"journal-issue":{"issue":"22","published-online":{"date-parts":[[2021,11]]}},"alternative-id":["s21227692"],"URL":"https:\/\/doi.org\/10.3390\/s21227692","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,11,19]]}}}