CHANGE ESR Athanasia Papanikolaou has successfully defended her thesis!
We are happy to announce that CHANGE ESR Athanasia Papanikolaou has defended her thesis titled «Portable multimodal system for measurement and monitoring of cultural heritage objects» at the Warsaw University of Technology 9th of February 2024. Congratulations, dr. Athanasia Papanikolaou!
Abstract of thesis
The main objective of this thesis is the development of methods and portable scientific instrumentation for measuring and monitoring of cultural heritage objects (CHOs) exposed to external loadings. CHOs, according to conservation recommendations, require noninvasive techniques. Initial implementations of the selected full-field optical measurement methods have indicated their high suitability for CHOs investigations. Within this framework, a combination of three incoherent imaging techniques have been proposed, namely Structured Light method (SL) for 3D shape determination, 3D Digital Image Correlation (3D DIC) for in plane, out of plane material investigations. As part of development and adaptation of these methods to CHOs requirements, the colour 3D DIC method (cDIC) was modified to enable the measurements based on a natural, colour CHOs texture. In particular a wide range of image demosaicking methods have been tested and evaluated with respect to the displacements accuracy. Also, a simplified MSI system has been developed by multiplexing the RGB camera channels sensitivities and the projector spectral power distribution. The spectral system consists of five discrete bands across the visible wavelength spectrum of 400-620nm. For cDIC and MS methods special measurement scenarios were developed and tested by examples of a historical parchment and paintings on canvas investigations. The structured light method with two cameras was also implemented for high accuracy registration of 3D CHOs shape (cloud of points (x,y,z)). At the next stage of work a portable opotmechatronics system has been designed and built. It is based on a digital light projector and two colour cameras, which enable capturing data for all three modalities. The integrated procedures for multimodal system calibration and data fusion in a common co-ordinate system were developed. Example measurement and data processing pipelines were presented for each modality and their arbitrary combinations. The full functionality of the system was presented by examples of measurements and monitoring of a historical parchment and painting mock-ups with defects exposed to humidity. The system enables a quick, non-invasive, non-destructive and low cost way to capture multimodal data for documentation, monitoring of 3D CHOs and planning conservation works.
Keywords: Cultural Heritage Objects; Full-field optical metrology; 2D and 3D data processing; Digital Image Correlation; Structured Light; 3D colour Digital Image Correlation; Multispectral Imaging; Multimodal Imaging
