{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,31]],"date-time":"2026-08-31T10:15:34Z","timestamp":1788171334848,"version":"build-2803163510"},"reference-count":20,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2026,8,31]],"date-time":"2026-08-31T00:00:00Z","timestamp":1788134400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>High-temperature oxidation affects the surface condition and quality of steel products, yet automated identification of the thermal stages governing oxide-scale formation remains limited. This study evaluated whether infrared thermography time series combined with dimensionality reduction and supervised learning could classify the heating, isothermal, and cooling phases of AISI 1045 steel oxidation. Five controlled Joule-heating experiments generated 3356 thermographic records. Each thermogram was flattened, and principal component analysis was applied independently to each experiment; the first two principal components were then used to train Random Forest, Multi-Layer Perceptron, Support Vector Machine, k-Nearest Neighbors, and XGBoost classifiers. Performance was assessed using leave-one-group-out cross-validation to preserve specimen-level independence. The Multi-Layer Perceptron achieved the best performance, with an accuracy of 0.8934, Macro-precision of 0.8740, Macro-recall of 0.8938, and Macro-F1-score of 0.8562. The highest class-specific area under the receiver operating characteristic curve was 0.95 for cooling. Most errors occurred between temporally adjacent phases, whereas confusion between heating and cooling was negligible, indicating physically consistent classification. These findings establish a proof of concept for automated thermal-phase recognition from raw thermographic sequences and support further validation under broader materials, processing conditions, and industrial environments.<\/jats:p>","DOI":"10.3390\/ma19173699","type":"journal-article","created":{"date-parts":[[2026,8,31]],"date-time":"2026-08-31T09:21:19Z","timestamp":1788168079000},"page":"3699","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Automatic Classification of Thermal Phases During Steel Oxidation via PCA and Infrared Thermography Time Series"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3669-2638","authenticated-orcid":false,"given":"Antony","family":"Morales-Cervantes","sequence":"first","affiliation":[{"name":"TecNM-Instituto Tecnol\u00f3gico de Morelia, Av. 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Metals, 9.","DOI":"10.3390\/met9020126"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"697","DOI":"10.2355\/isijinternational.55.697","article-title":"Effect of Surface Oxidization on the Normal Spectral Emissivity of Straight Carbon Steel at 800\u20131100 K in Air","volume":"55","author":"Shi","year":"2015","journal-title":"ISIJ Int."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Morales-Cervantes, A., Vergara-Hern\u00e1ndez, H.J., Guevara, E., T\u00e9llez-Mart\u00ednez, J.S., and Ch\u00e1vez-Campos, G.M. (2025). Real-Time Detection and Monitoring of Oxide Layer Formation in 1045 Steel Using Infrared Thermography and Advanced Image Processing Algorithms. Materials, 18.","DOI":"10.3390\/ma18050954"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"106806","DOI":"10.1016\/j.csite.2025.106806","article-title":"Infrared thermography for spatiotemporal analysis of high-temperature oxidation dynamics in AISI 1045 steel","volume":"74","year":"2025","journal-title":"Case Stud. Therm. Eng."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Peng, S., Addepalli, S., and Farsi, M. (2025). Machine Learning in Thermography Non-Destructive Testing: A Systematic Review. Appl. Sci., 15.","DOI":"10.3390\/app15179624"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"115292","DOI":"10.1016\/j.optlastec.2026.115292","article-title":"Machine learning-based detection technology for electron beam and laser processing","volume":"201","author":"Meng","year":"2026","journal-title":"Opt. Laser Technol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"114656","DOI":"10.1016\/j.commatsci.2026.114656","article-title":"Research on defect detection performance of silicon carbide wafer surface based on ESN-YOLOv8 algorithm","volume":"268","author":"Yang","year":"2026","journal-title":"Comput. Mater. Sci."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"20150202","DOI":"10.1098\/rsta.2015.0202","article-title":"Principal component analysis: A review and recent developments","volume":"374","author":"Jolliffe","year":"2016","journal-title":"Philos. Trans. R. Soc. A Math. Phys. Eng. Sci."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"102818","DOI":"10.1016\/j.ndteint.2023.102818","article-title":"Analyzing a series of thermal infrared images to identify defects using a hybrid approach that combines robust principal component analysis and image segmentation","volume":"137","author":"Huang","year":"2023","journal-title":"NDT E Int."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Prieto-S\u00e1nchez, O.D., Morales-Cervantes, A., T\u00e9llez-Mart\u00ednez, J.S., Ch\u00e1vez-Campos, G.M., Guevara, E., and Vergara-Hern\u00e1ndez, H.J. (2026). Kinetic oxidation analysis in AISI 1045 steel using infrared thermography and convolutional neural networks. Materials, 19.","DOI":"10.3390\/ma19050920"},{"key":"ref_14","unstructured":"Bauccio, M. (1993). ASM Metals Reference Book, ASM International. [3rd ed.]."},{"key":"ref_15","unstructured":"Optris (2026, August 26). Operating Instructions and Data Sheets for Optris PI IR Cameras. Available online: https:\/\/optris.com\/support-service\/downloads\/."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"e202200055","DOI":"10.1002\/jbio.202200055","article-title":"Feasibility of Raman spectroscopy as a potential in vivo tool to screen for pre-diabetes and diabetes","volume":"15","author":"Guevara","year":"2022","journal-title":"J. Biophotonics"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1967","DOI":"10.1007\/s40200-024-01452-0","article-title":"Digital infrared thermography and machine learning for diabetic foot assessment: Thermal patterns and classification","volume":"23","author":"Guevara","year":"2024","journal-title":"J. Diabetes Metab. Disord."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"156","DOI":"10.1007\/s43939-025-00323-6","article-title":"Hybrid machine learning and regression framework for automated phase classification and quantification in SEM images of commercial steels","volume":"5","author":"Hiremath","year":"2025","journal-title":"Discov. Mater."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"271","DOI":"10.1016\/j.cirp.2009.03.050","article-title":"Deformation of oxide scale on steel surface during hot rolling","volume":"58","author":"Utsunomiya","year":"2009","journal-title":"CIRP Ann."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"073102","DOI":"10.1063\/1.4939746","article-title":"The phase transition in VO2 probed using x-ray, visible and infrared radiations","volume":"108","author":"Kumar","year":"2016","journal-title":"Appl. Phys. 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