Qualitative Assessments via Infrared Vision of Sub-surface Defects Present Beneath Decorative Surface Coatings

  • Stefano Sfarra
  • Henrique C. Fernandes
  • Fernando López
  • Clemente Ibarra-Castanedo
  • Hai Zhang
  • Xavier Maldague


In this work, the potentialities of the infrared vision to explore sub-superficial defects in polychromatic statues were investigated. In particular, it was possible to understand how the reflector effect of the exterior golden layers could be minimized, applying advanced statistical algorithms to thermal images. Since this noble metal is present as external coating in both artworks, an in-depth discussion concerning its physicochemical properties is also added. In this context, the principal component thermography technique and, the more recent, partial least squares thermography technique were used on three different datasets recorded, providing long thermal stimuli. The main images were compared both to phasegrams and to the thermographic signal reconstruction results in order to have a clear outline of the situation to be debated. The effects of view factors on the radiation transfer linked to the specular reflections from the surface did not falsely highlight certain features inadvertently. Indeed, the raw thermograms were analyzed one by one. Reflectograms were used to pinpoint emissivity variations due to, e.g., possible repainting. The paper concludes that, as it is possible to understand from a physical point of view, the near-infrared reflectography technique is able to examine the state of conservation of the upper layers in cultural heritage objects, while the infrared thermography technique explores them more in-depth. The thesis statement is based on the thermal and nonthermal parts of the infrared region, therefore, indicating what can be detected by heating the surface and what can be visualized by illuminating the surface, bearing in mind the nature of the external coating.


Defect Gilded coatings Infrared thermography (IRT) Near-infrared reflectography (NIRR) Polychromatic statues Statistical algorithms 



The authors would like to thank Ms. Annette Schwerdtfeger from the Department of Electrical and Computer Engineering at Laval University (Canada) for her constructive revision of the English language. The authors wish also to thank Dr. Geltrude Di Matteo (director) and Mr. Alessandro Verrocchia (chief restorer), of the Musé “Il Museo delle Paludi di Celano,” Italy, for their kind cooperation in this work. The authors are also in debt with Mr. Giovanni Pasqualoni of the Las.E.R. Laboratory (L’Aquila, Italy), for the technical support during the thermographic acquisitions. This study was supported by Russian Foundation Grant #17-19-01047 and in part by Tomsk Polytechnic University Competitiveness Enhancement Program grant.


  1. 1.
    I. Crina Anca Sandu, M.H. de Sá, M.C. Pereira, Surf. Interface Anal. 43, 1134 (2011)CrossRefGoogle Scholar
  2. 2.
    E. Hecht, A. Zając, Optics, 4th edn. (Pearson Education Limited, Hoboken, 2001)Google Scholar
  3. 3.
    R.L. Feller, Artists Pigments: A Handbook of Their History and Characteristics, vol. 1 (Cambridge University Press, London, 1987)Google Scholar
  4. 4.
    H.A. Gardner, G.G. Sward, Paint Testing Manual, 13th edn. (ASTM International, Philadelphia, 1972)Google Scholar
  5. 5.
    R.J. Gettens, G.L. Stout, Painting Materials: A Short Encyclopedia (Dover Publications, London, 2011)Google Scholar
  6. 6.
    A.P. Laurie, The Painters Methods and Materials (Dover Publications, New York, 1988)Google Scholar
  7. 7.
    S.A. Humphrey, P.J. Laden, Gold Bronze Pigment in Pigments Handbook. Properties and Economics, vol. 1 (Wiley, New York, 1988), pp. 803–810Google Scholar
  8. 8.
    J.V. Koleske, Paint and Coating Testing Manual (Fourteenth Edition of the Gardner-Sward Handbook), ASTM Manual Series: MLN 17, Philadelphia (PA) (1995)Google Scholar
  9. 9.
    H.S. Carslaw, J.C. Jaeger, Conduction of Heat in Solids, 2nd edn. (Clarendon Press, Oxford, 1959)MATHGoogle Scholar
  10. 10.
    Y.V. Petrov, N.A. Inogamov, K.P. Migdal, Two-temperature heat conductivity of gold, in Proceedings of Progress in Electromagnetics Research Symposium, Prague, Czech Republic (2015)Google Scholar
  11. 11.
    J.R.J. Van Asperen de Boer, Appl. Opt. 7, 1711 (1968)ADSCrossRefGoogle Scholar
  12. 12.
    X.P.V. Maldague, Theory and Practice of Infrared Technology for Nondestructive Testing (Wiley, New York, 2001)Google Scholar
  13. 13.
    A.M. Reggiani, Recuperata statua Terracotta attribuita a Saturnino Gatti, L’Editoriale online (2009). turismo=803. Accessed 21 Apr 2016
  14. 14.
    E. Santilli, Silvestro di Giacomo da Sulmona, detto Silvestro Aquilano (ca. 1450–1504). Scultore, pittore, figulo, architetto, Regione Abruzzo—Assessorato alla Cultura (2012). file:///C:/Users/Utente/Downloads/SILVESTRObiografia1.pdf. Accessed 21 Apr 2016Google Scholar
  15. 15.
    P. Conti, La Madonna scampata al sisma perde pezzi alla mostra ‘per’ il sisma, Corriere della (2009). Accessed 21 Apr 2016
  16. 16.
    M. Corridore, Statua della Madonna di Saturnino Gatti ritrovata a Londra, Il Centro (2016). Accessed 21 Apr 2016
  17. 17.
    F. Verlengia, Pompeo Cesura. Pittore aquilano del ‘500, Stabilimento Poligrafico Editoriale Amoroso, Pescara (1958)Google Scholar
  18. 18.
    F. Mercuri, N. Orazi, U. Zammit, S. Paoloni, M. Marinelli, P.P. Valentini, e-PS 9, 84 (2012)Google Scholar
  19. 19.
    S. Sfarra, C. Ibarra-Castanedo, S. Ridolfi, G. Cerichelli, D. Ambrosini, D. Paoletti, X. Maldague, Appl. Phys. A. Mater. 115, 1041 (2014)ADSCrossRefGoogle Scholar
  20. 20.
    B.-H. Mevik, R. Wehrens, J. Stat. Softw. 18, 1 (2007)CrossRefGoogle Scholar
  21. 21.
    N. Rajic, Compos. Struct. 58, 521 (2002)CrossRefGoogle Scholar
  22. 22.
    P. Bison, A. Bortolin, G. Cadelano, G. Ferrarini, F. López, X. Maldague, Evaluation of frescoes detachments by partial least squares thermography, in Proceedings of the International Conference on Quantitative Infrared Thermography (QIRT) (2014)Google Scholar
  23. 23.
    P. Bison, A. Bortolin, G. Cadelano, G. Ferrarini, F. López, X. Maldague, Comparison of image processing techniques for the on-site evaluation of damaged frescoes, in Proceedings of SPIE—The International Society for Optical Engineering, Thermosense XXXVI (2014)Google Scholar
  24. 24.
    F. López, C. Ibarra-Castanedo, V. de Paulo Nicolau, X. Maldague, NDT&E Int. 66, 128 (2014)CrossRefGoogle Scholar
  25. 25.
    X. Maldague, S. Marinetti, J. Appl. Phys. 79, 2694 (1996)ADSCrossRefGoogle Scholar
  26. 26.
    S.M. Shepard, J.R. Lhota, B.A. Rubadeux, D. Wang, T. Ahmed, Opt. Eng. 42, 1337 (2003)ADSCrossRefGoogle Scholar
  27. 27.
    S.M. Shepard, Mater. Eval. 65, 690 (2007)Google Scholar
  28. 28.
    D.L. Balageas, J.M. Roche, F.-H. Leroy, W.-M. Liu, A.M. Gorbach, Biocybern. Biomed. Eng. 35, 1–9 (2015)CrossRefGoogle Scholar
  29. 29.
    M.T. Klein, C. Ibarra-Castanedo, X. Maldague, A. Bendada, A straightforward graphical user interface for basic and advanced signal processing of thermographic infrared sequences, in Proceedings of SPIE—The International Society for Optical Engineering, Thermosense XXX (2008)Google Scholar
  30. 30.
    S. Sfarra, C. Ibarra-Castanedo, D. Paoletti, X. Maldague, Mater. Eval. 71, 561 (2013)Google Scholar
  31. 31.
    A. Bayler, A. Schier, G.A. Bowmaker, H. Schmidbaur, J. Am. Chem. Soc. 188, 7006 (1996)CrossRefGoogle Scholar
  32. 32.
    P.K. Mehrotra, R. Hoffmann, Inorganic Chem. 17, 2187 (1978)CrossRefGoogle Scholar
  33. 33.
    H.E. Merwin, Optical properties and theory of color of pigments and paints, in Proceedings of the American Society for Testing Materials XVII (1917)Google Scholar
  34. 34.
    A.D. Rakiḉ, A.B. Djurišic, J.M. Elazar, M.L. Majewski, Appl. Opt. 37, 5271 (1998)ADSCrossRefGoogle Scholar
  35. 35.
    C. Chiojdeanu, D. Cristea Stan, B. Constantinescu, Roman. Rep. Phys. 63, 685 (2011)Google Scholar
  36. 36.
    G. Hanlon, Why some paints are transparent and others opaque. Natural Pigments (2013). Accessed 21 April 2016
  37. 37.
    M. Gimeno Concepción, The chemistry of gold, in Modern Supramolecular Gold Chemistry: Gold-Metal Interactions and Applications, ed. by A. Laguna (Wiley-VCH, New York, 2008), pp. 1–64Google Scholar
  38. 38.
    F. López, X. Maldague, C. Ibarra-Castanedo, Opto-Electron. Rev. 22, 245 (2014)ADSCrossRefGoogle Scholar
  39. 39.
    S. Sfarra, C. Ibarra-Castanedo, D. Ambrosini, D. Paoletti, A. Bendada, X. Maldague, Arab. J. Sci. Eng. 39, 3461 (2014)CrossRefGoogle Scholar
  40. 40.
    P. Kubelka, F. Munk, Zeits. f. Techn. Physik 12, 593 (1931)Google Scholar
  41. 41.
    P. Miracola, Il restauro di due opera in terracotta dipinta: Il presepe di Santa Maria del Ponte e la Madonna di Collemaggio, Gangemi Ed., Italy (2015)Google Scholar
  42. 42.
    N. Penni, The Materials of Sculpture (Yale University Press, London, 1993)Google Scholar
  43. 43.
    R. Mayer, The Artist’s Handbook of Materials and Techniques, 5th edn. (Faber & Faber, London, 1991)Google Scholar
  44. 44.
    C. Ibarra-Castanedo, Ph.D. thesis, Laval University, Quebec City, QC, Canada (2005). Accessed 1 June 2017
  45. 45.
    S. Sfarra, P. Theodorakeas, C. Ibarra-Castanedo, N.P. Avdelidis, D. Ambrosini, E. Cheilakou, D. Paoletti, M. Koui, A. Bendada, X. Maldague, Int. J. Thermophys. 36, 3051 (2015)ADSCrossRefGoogle Scholar
  46. 46.
    C. Ibarra-Castanedo, S. Sfarra, D. Ambrosini, D. Paoletti, A. Bendada, X. Maldague, QIRT J. 5, 131 (2008)CrossRefGoogle Scholar
  47. 47.
    C. Ibarra-Castanedo, S. Sfarra, D. Ambrosini, D. Paoletti, A. Bendada, X. Maldague, QIRT J. 7, 85 (2010)CrossRefGoogle Scholar
  48. 48.
    C. Ibarra-Castanedo, S. Sfarra, D. Paoletti, A. Bendada, X. Maldague, Nondestructive testing of externally reinforced structures for seismic retrofitting using flax fiber reinforced polymer (FFRP) composites, in Proceedings of SPIE—The International Society for Optical Engineering, Thermosense XXXV (2013)Google Scholar
  49. 49.
    F. López, V.P. Nicolau, C. Ibarra-Castanedo, S. Sfarra, X. Maldague, Comparative study of thermographic signal reconstruction and partial least squares thermography for the detection and evaluation of subsurface defects, in Proceedings of the International Conference on Quantitative Infrared Thermography (QIRT) (2014)Google Scholar
  50. 50.
    S. Sfarra, C. Ibarra-Castanedo, D. Ambrosini, D. Paoletti, A. Bendada, X. Maldague, J. Nondestruct. Eval. 33, 358 (2014)CrossRefGoogle Scholar
  51. 51.
    M. Tortora, S. Sfarra, M. Chiarini, V. Daniele, G. Taglieri, G. Cerichelli, Appl. Surf. Sci. 387, 971 (2016)ADSCrossRefGoogle Scholar
  52. 52.
    Y. Duan, S. Huebner, U. Hassler, A. Osman, C. Ibarra-Castanedo, X.P.V. Maldague, Infr. Phys. Technol. 60, 275 (2013)ADSCrossRefGoogle Scholar
  53. 53.
    R. Yang, Y. He, B. Gao, G.Y. Tian, Appl. Phys. Lett. 105, 184103 (2014)ADSCrossRefGoogle Scholar
  54. 54.
    G. Taglieri, V. Daniele, G. Rosatelli, S. Sfarra, M.C. Mascolo, C. Mondelli, J. Cult. Herit. 25, 135 (2017)CrossRefGoogle Scholar
  55. 55.
    R. Cesareo, G. Buccolieri, A. Castellano, R.T. Lopes, J.T. De Assis, S. Ridolfi, A. Brunetti, A. Bustamante, X-Ray Spectrom. 44, 233 (2015)ADSCrossRefGoogle Scholar
  56. 56.
    H. Zhang, S. Sfarra, K. Saluja, J. Peeters, J. Fleuret, Y. Duan, H. Fernandes, N. Avdelidis, C. Ibarra-Castanedo, X. Maldague, J. Nondestruct. Eval. 36, 1 (2017)CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2017

Authors and Affiliations

  • Stefano Sfarra
    • 1
    • 2
    • 4
    • 5
  • Henrique C. Fernandes
    • 3
  • Fernando López
    • 4
  • Clemente Ibarra-Castanedo
    • 4
  • Hai Zhang
    • 4
  • Xavier Maldague
    • 4
  1. 1.Las.E.R. Laboratory, Department of Industrial and Information Engineering and EconomicsUniversity of L’AquilaMonteluco di RoioItaly
  2. 2.Tomsk Polytechnic UniversityTomskRussia
  3. 3.Department of Computer ScienceFederal University of UberlândiaUberlândiaBrazil
  4. 4.Computer Vision and Systems Laboratory, Department of Electrical and Computer EngineeringLaval UniversityQuebec CityCanada
  5. 5.INFN CHNetLaboratori Nazionali del Gran SassoAssergiItaly

Personalised recommendations