{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,22]],"date-time":"2025-10-22T18:12:33Z","timestamp":1761156753521,"version":"build-2065373602"},"reference-count":55,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2019,10,8]],"date-time":"2019-10-08T00:00:00Z","timestamp":1570492800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100010661","name":"Horizon 2020 Framework Programme","doi-asserted-by":"publisher","award":["722134"],"award-info":[{"award-number":["722134"]}],"id":[{"id":"10.13039\/100010661","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The use of different spectral bands in the inspection of artworks is highly recommended to identify the maximum number of defects\/anomalies (i.e., the targets), whose presence ought to be known before any possible restoration action. Although an artwork cannot be considered as a composite material in which the zero-defect theory is usually followed by scientists, it is possible to state that the preservation of a multi-layered structure fabricated by the artist\u2019s hands is based on a methodological analysis, where the use of non-destructive testing methods is highly desirable. In this paper, the infrared thermography and hyperspectral imaging methods were applied to identify both fabricated and non-fabricated targets in a canvas painting mocking up the famous character \u201cVenus\u201d by Botticelli. The pulse-compression thermography technique was used to retrieve info about the inner structure of the sample and low power light-emitting diode (LED) chips, whose emission was modulated via a pseudo-noise sequence, were exploited as the heat source for minimizing the heat radiated on the sample surface. Hyper-spectral imaging was employed to detect surface and subsurface features such as pentimenti and facial contours. The results demonstrate how the application of statistical algorithms (i.e., principal component and independent component analyses) maximized the number of targets retrieved during the post-acquisition steps for both the employed techniques. Finally, the best results obtained by both techniques and post-processing methods were fused together, resulting in a clear targets map, in which both the surface, subsurface and deeper information are all shown at a glance.<\/jats:p>","DOI":"10.3390\/s19194335","type":"journal-article","created":{"date-parts":[[2019,10,8]],"date-time":"2019-10-08T09:00:38Z","timestamp":1570525238000},"page":"4335","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":16,"title":["Looking Through Paintings by Combining Hyper-Spectral Imaging and Pulse-Compression Thermography"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7283-2004","authenticated-orcid":false,"given":"Stefano","family":"Laureti","sequence":"first","affiliation":[{"name":"Department of Informatics, Modeling, Electronics and Systems Engineering, University of Calabria, Via P.Bucci, Arcavacata, 87036 Rende (CS), Italy"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8042-2339","authenticated-orcid":false,"given":"Hamed","family":"Malekmohammadi","sequence":"additional","affiliation":[{"name":"Department of Engineering, Polo Scientifico Didattico di Terni, University of Perugia, 05100 Terni (TR), Italy"}]},{"given":"Muhammad Khalid","family":"Rizwan","sequence":"additional","affiliation":[{"name":"Department of Engineering, Polo Scientifico Didattico di Terni, University of Perugia, 05100 Terni (TR), Italy"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4094-7621","authenticated-orcid":false,"given":"Pietro","family":"Burrascano","sequence":"additional","affiliation":[{"name":"Department of Engineering, Polo Scientifico Didattico di Terni, University of Perugia, 05100 Terni (TR), Italy"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9354-4650","authenticated-orcid":false,"given":"Stefano","family":"Sfarra","sequence":"additional","affiliation":[{"name":"Department of Industrial and Information Engineering and Economics, University of L\u2019Aquila, 67100 L\u2019Aquila (AQ), Italy"}]},{"given":"Miranda","family":"Mostacci","sequence":"additional","affiliation":[{"name":"Restorer, Via Muranuove 64, 67043 Celano (AQ), Italy"}]},{"given":"Marco","family":"Ricci","sequence":"additional","affiliation":[{"name":"Department of Informatics, Modeling, Electronics and Systems Engineering, University of Calabria, Via P.Bucci, Arcavacata, 87036 Rende (CS), Italy"}]}],"member":"1968","published-online":{"date-parts":[[2019,10,8]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"234","DOI":"10.1134\/S1061830913040062","article-title":"Thermographic, ultrasonic and optical methods: A new dimension in veneered wood diagnostics","volume":"49","author":"Sfarra","year":"2013","journal-title":"Russ. J. Nondestr. Test."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"21","DOI":"10.1784\/insi.2012.54.1.21","article-title":"Evaluation of defects in panel paintings using infrared, optical and ultrasonic techniques","volume":"54","author":"Sfarra","year":"2012","journal-title":"Insight"},{"key":"ref_3","first-page":"1366","article-title":"Non-destructive testing for the analysis of moisture in the masonry arch bridge of Lubians (Spain)","volume":"20","author":"Solla","year":"2013","journal-title":"Struct. Control Health Monit."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1083","DOI":"10.1007\/s10973-019-08005-1","article-title":"Precious walls built in indoor environments inspected numerically and experimentally within long-wave infrared (LWIR) and radio regions","volume":"137","author":"Sfarra","year":"2019","journal-title":"J. Therm. Anal. Calorim."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Puente, I., Solla, M., Lag\u00fcela, S., and Sanjurjo-Pinto, J. (2018). Reconstructing the Roman Site \u201cAquis Querquennis\u201d(Bande, Spain) from GPR, T-LiDAR and IRT Data Fusion. Remote Sens., 10.","DOI":"10.3390\/rs10030379"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"115601","DOI":"10.1088\/0957-0233\/23\/11\/115601","article-title":"From the experimental simulation to integrated non-destructive analysis by means of optical and infrared techniques: Results compared","volume":"23","author":"Sfarra","year":"2012","journal-title":"Meas. Sci. Technol."},{"key":"ref_7","unstructured":"Maldague, X.P.V. (2001). Theory and Practice of Infrared Technology for Non-Destructive Testing, Wiley."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"34","DOI":"10.1007\/s10921-017-0414-8","article-title":"Non-destructive investigation of paintings on canvas by continuous wave terahertz imaging and flash thermography","volume":"36","author":"Zhang","year":"2017","journal-title":"J. Nondestruct. Eval."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"131","DOI":"10.3166\/qirt.5.131-149","article-title":"Subsurface defect characterization in artworks by quantitative pulsed phase thermography and holographic interferometry","volume":"5","author":"Sfarra","year":"2008","journal-title":"QIRT J."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"85","DOI":"10.3166\/qirt.7.85-114","article-title":"Diagnostics of panel paintings using holographic interferometry and pulsed thermography","volume":"7","author":"Sfarra","year":"2010","journal-title":"QIRT J."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"2070","DOI":"10.1021\/acs.accounts.6b00048","article-title":"Reflectance hyperspectral imaging for investigation of works of art: Old master paintings and illuminated manuscripts","volume":"49","author":"Cucci","year":"2016","journal-title":"Acc. Chem. Res."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"309","DOI":"10.1007\/s00339-011-6689-1","article-title":"Advances in multispectral and hyperspectral imaging for archaeology and art conservation","volume":"106","author":"Liang","year":"2012","journal-title":"Appl. Phys. A"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"147","DOI":"10.1016\/j.ndteint.2018.05.003","article-title":"The use of pulse-compression thermography for detecting defects in paintings","volume":"98","author":"Laureti","year":"2018","journal-title":"NDT&E Int."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Laureti, S., Colantonio, C., Burrascano, P., Melis, M., Calabr\u00f2, G., Malekmohammadi, H., Sfarra, S., Ricci, M., Ricci, M., and Pelosi, C. (2019). Development of integrated innovative techniques for paintings examination: The case studies of The Resurrection of Christ attributed to Andrea Mantegna and the Crucifixion of Viterbo attributed to Michelangelo\u2019s workshop. J. Cult. Herit., in press.","DOI":"10.1016\/j.culher.2019.05.005"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"521","DOI":"10.1016\/S0263-8223(02)00161-7","article-title":"Principal component thermography for flaw contrast enhancement and flaw depth characterization in composite structures","volume":"58","author":"Rajic","year":"2002","journal-title":"Compos. Struct."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1016\/j.ndteint.2018.07.004","article-title":"Image Processing based Quantitative Damage Evaluation in Composites with Long Pulse Thermography","volume":"99","author":"Wang","year":"2018","journal-title":"NDT E Int."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"102155","DOI":"10.1016\/j.ndteint.2019.102155","article-title":"Comparative analysis of eddy current pulsed thermography and long pulse thermography for damage detection in metals and composites","volume":"107","author":"Wang","year":"2019","journal-title":"NDT E Int."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Winfree, W.P., Cramer, K.E., Zalameda, J.N., Howell, P.A., and Burke, E.R. (,  2015). Principal component analysis of thermographic data. Proceedings of the Thermosense: Thermal Infrared Applications XXXVII; International Society for Optics and Photonics, Washington, DC, USA.","DOI":"10.1117\/12.2176285"},{"key":"ref_19","first-page":"215","article-title":"Processing of thermographic sequence using Principal Component Analysis","volume":"61","year":"2015","journal-title":"Meas. Autom. Monit."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"85","DOI":"10.1016\/j.infrared.2004.03.012","article-title":"Statistical analysis of IR thermographic sequences by PCA","volume":"46","author":"Marinetti","year":"2004","journal-title":"Infrared Phys. Technol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"358","DOI":"10.1016\/j.infrared.2010.06.004","article-title":"A combined approach of self-referencing and Principle Component Thermography for transient, steady, and selective heating scenarios","volume":"53","author":"Omar","year":"2010","journal-title":"Infrared Phys. Technol."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"411","DOI":"10.1016\/S0893-6080(00)00026-5","article-title":"Independent component analysis: Algorithms and applications","volume":"13","author":"Oja","year":"2000","journal-title":"Neural Netw."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/s10765-017-2333-4","article-title":"Qualitative assessments via infrared vision of sub-surface defects present beneath decorative surface coatings","volume":"39","author":"Sfarra","year":"2018","journal-title":"Int. J. Thermophys."},{"key":"ref_24","unstructured":"(2017, July 04). The Birth of Venus. Available online: http:\/\/www.art-renaissance.net\/Botticelli\/Birth-Venus-Botticelli-children.pdf."},{"key":"ref_25","unstructured":"Zucco, M., Pisani, M., and Cavaleri, T. (2019, October 06). Fourier Transform Hyperspectral Imaging for Cultural Heritage, Fourier Transforms\u2014High-Tech Application and Current Trends. Available online: https:\/\/www.intechopen.com\/books\/fourier-transforms-high-tech-application-and-current-trends\/fourier transform-hyperspectral-imaging-for-cultural-heritage."},{"key":"ref_26","first-page":"299","article-title":"A review on image stitching and its different methods","volume":"5","author":"Shikha","year":"2015","journal-title":"Int. J. Adv. Res. Comput. Sci. and Software Eng."},{"key":"ref_27","first-page":"2","article-title":"Introduction to infrared and thermal testing: Part 1 Nondestructive Testing","volume":"Volume 3","author":"Maldague","year":"2001","journal-title":"Nondestructive Handbook, Infrared and Thermal Testing"},{"key":"ref_28","first-page":"561","article-title":"Infrared vision inspection of cultural heritage objects from the city of L\u2019Aquila, Italy and its surroundings","volume":"71","author":"Sfarra","year":"2013","journal-title":"Mater. Eval."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Maldague, X. (1993). Nondestructive Evaluation of Materials by Infrared Thermography, Springer. [1st ed.].","DOI":"10.1007\/978-1-4471-1995-1"},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Seeboth, A., and L\u00f6tzsch, D. (2013). Thermochromic and Thermotropic Materials, Jenny Standford Publishing (Taylor & Francis Group). [1st ed.].","DOI":"10.1201\/b16299"},{"key":"ref_31","first-page":"1","article-title":"Relationship between Na2SO4 concentration and thermal response of reconstituted stone in the laboratory and on site","volume":"75","author":"Gommeaux","year":"2016","journal-title":"Environ. Earth Sci."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"3051","DOI":"10.1007\/s10765-015-1962-8","article-title":"How to retrieve information inherent to old restorations made on frescoes of particular artistic value using infrared vision?","volume":"36","author":"Sfarra","year":"2015","journal-title":"Int. J. Thermophys."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"88","DOI":"10.1179\/2047058413Y.0000000117","article-title":"Active infrared thermography applied to the study of a painting on paper representing the Chigi\u2019s family tree","volume":"60","author":"Pucci","year":"2015","journal-title":"Stud. Conserv."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"054902","DOI":"10.1063\/1.3594551","article-title":"Coded excitation for infrared non-destructive testing of carbon fiber reinforced plastics","volume":"82","author":"Mulaveesala","year":"2011","journal-title":"Rev. Sci. Instrum."},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Laureti, S., Khalid Rizwan, M., Malekmohammadi, H., Burrascano, P., Natali, M., Torre, L., and Ricci, M. (2019). Delamination Detection in Polymeric Ablative Materials Using Pulse-Compression Thermography and Air-Coupled Ultrasound. Sensors, 19.","DOI":"10.3390\/s19092198"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"2328","DOI":"10.1007\/s10765-015-1890-7","article-title":"Thermodynamic limits of spatial resolution in active thermography","volume":"36","author":"Bulgholzer","year":"2015","journal-title":"Int. J. Thermophys."},{"key":"ref_37","unstructured":"Carslaw, H.S., and Jaeger, J.C. (1959). Conduction of Heat in Solids, Oxford Claredon Press. [2nd ed.]."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1080\/17686733.2014.891324","article-title":"Common tools for quantitative time-resolved pulse and step-heating thermography\u2014Part I: Theoretical basis","volume":"11","author":"Balageas","year":"2014","journal-title":"QIRT J."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"100","DOI":"10.1016\/j.ndteint.2017.01.011","article-title":"Optimization of the pulse-compression technique applied to the infrared thermography nondestructive evaluation","volume":"87","author":"Silipigni","year":"2017","journal-title":"NDT E Int."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1063\/1.3095560","article-title":"Thermal-wave radar: A novel subsurface imaging modality with extended depth-resolution dynamic range","volume":"80","author":"Tabatabaei","year":"2009","journal-title":"Rev. Sci. Instrum."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"191913","DOI":"10.1063\/1.2382738","article-title":"Theory of frequency modulated thermal wave imaging for nondestructive subsurface defect detection","volume":"89","author":"Mulaveesala","year":"2006","journal-title":"Appl. Phys. Lett."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"655","DOI":"10.1016\/j.ndteint.2011.06.008","article-title":"A comparison of the pulsed, lock-in and frequency modulated thermography nondestructive evaluation techniques","volume":"44","author":"Chatterjee","year":"2011","journal-title":"NDT E Int."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"311","DOI":"10.1109\/TIT.1960.1057571","article-title":"An introduction to matched filters","volume":"6","author":"Turin","year":"1960","journal-title":"IRE Trans. Inf. Theory"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"208","DOI":"10.1109\/TUFFC.2005.1406547","article-title":"Use of modulated excitation signals in medical ultrasound. Part III: High frame rate imaging","volume":"52","author":"Misaridis","year":"2005","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"376","DOI":"10.1049\/el:20020220","article-title":"Pseudonoise codes constructed by Legendre sequence","volume":"38","author":"Zhang","year":"2002","journal-title":"Electron. Lett."},{"key":"ref_46","first-page":"273","article-title":"Group synchronizing of binary digital systems","volume":"38","author":"Barker","year":"1953","journal-title":"Commun. Theory."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"D32","DOI":"10.1364\/AO.57.000D32","article-title":"Comparative study between linear and non-linear frequency-modulated pulse-compression thermography","volume":"57","author":"Laureti","year":"2018","journal-title":"Appl. Opt."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"2905","DOI":"10.1109\/TIM.2012.2200409","article-title":"Exploiting pseudorandom sequences to enhance noise immunity for air-coupled ultrasonic nondestructive testing","volume":"61","author":"Ricci","year":"2012","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"1745","DOI":"10.1016\/j.ultras.2014.03.007","article-title":"Coded waveforms for optimised air-coupled ultrasonic nondestructive evaluation","volume":"54","author":"Hutchins","year":"2014","journal-title":"Ultrasonics."},{"key":"ref_50","doi-asserted-by":"crossref","unstructured":"Rangel, J., Soldan, S., and Kroll, A. (2014, January 7\u201311). 3D Thermal Imaging: Fusion of Thermography and Depth Cameras. Proceedings of the 12th International Conference on Quantitative Infrared Thermography, Bordeaux France.","DOI":"10.21611\/qirt.2014.035"},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"044006","DOI":"10.1088\/1361-6501\/ab02db","article-title":"Independent component thermography for non-destructive testing of defects in polymer composites","volume":"30","author":"Liu","year":"2019","journal-title":"Meas. Sci. Technol."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"143","DOI":"10.1016\/j.ijthermalsci.2017.12.036","article-title":"Active thermography testing and data analysis for the state of conservation of panel paintings","volume":"126","author":"Yao","year":"2018","journal-title":"Int. J. Therm. Sci."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"283","DOI":"10.1515\/secm-2013-0138","article-title":"Monitoring of jute\/hemp fiber hybrid laminates by nondestructive testing techniques","volume":"23","author":"Sfarra","year":"2016","journal-title":"Sci. Eng. Compos. Mater."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"45","DOI":"10.1016\/j.infrared.2019.02.006","article-title":"An independent component analysis based approach for frequency modulated thermal wave imaging for subsurface defect detection in steel sample","volume":"98","author":"Ahmad","year":"2019","journal-title":"Infrared Phy. Technol."},{"key":"ref_55","first-page":"544","article-title":"Application of image fusion for the IR images in frequency modulated thermal wave imaging for Non Destructive Testing (NDT)","volume":"5","author":"Reddy","year":"2019","journal-title":"Mater. Today Proc."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/19\/4335\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T13:28:12Z","timestamp":1760189292000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/19\/4335"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,10,8]]},"references-count":55,"journal-issue":{"issue":"19","published-online":{"date-parts":[[2019,10]]}},"alternative-id":["s19194335"],"URL":"https:\/\/doi.org\/10.3390\/s19194335","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2019,10,8]]}}}