Author Affiliations
Abstract
1 Foundation for Research and Technology Hellas, Institute of Electronic Structure and Laser, N. Plastira 100, Heraklion, Crete 70013, Greece
2 Department of Physics, University of Crete, Voutes University Campus, Crete 71003, Greece
In the context of this work, a prototype hybrid photoacoustic (PA) and optical system for the on-line monitoring of laser cleaning procedures is presented. The developed apparatus has enabled the detection of MHz frequency range acoustic waves generated during the laser ablation process. The intrinsically generated PA signals combined with high resolution optical images provide the opportunity to follow the cleaning process accurately and in real time. Technical mock-ups have been used to demonstrate the potential of this novel technique with emphasis given to applications that refer to the restoration of Cultural Heritage (CH) surfaces. Towards this purpose, the real time monitoring of the laser assisted removal of unwanted encrustation from stonework has been achieved using IR and UV wavelengths. This novel approach has allowed for the precise determination of the critical number of laser pulses required for the elimination of the encrustation layer, while highlighting the dominant ablation mechanisms according to the irradiation wavelength. The promising results obtained using the prototype hybrid PA and optical system can open up new perspectives in the monitoring of laser cleaning interventions, promoting an improved restoration outcome.
photoacoustic monitoring laser cleaning encrusted marble real time monitoring two-wavelengths cleaning Opto-Electronic Advances
2020, 3(2): 02190037
Author Affiliations
Abstract
1 Institute of Electronic Structure and Laser Foundation for Research and Technology, Hellas 71110 Heraklion, Crete, Greece
2 Institute of Molecular Biology and Biotechnology Foundation for Research and Technology, Hellas 71110 Heraklion, Crete, Greece
Even though multispectral imaging is considered very significant in biological imaging, it is only commonly used in microscopy in a 2D approach. Here, we present a Fluorescence Molecular Tomography system capable of recording simultaneously tomographic data at several spectral windows, enabling multispectral tomography. 3D reconstructed data from several spectral windows is used to construct a linear unmixing algorithm for multispectral deconvolution of overlapping fluorescence signals. The method is applied on tomographic 3D fluorescence concentration maps in tissue-mimicking phantoms, yielding absolute quantification of the concentration of each individual fluorophore. Results are compared to the case when unmixing is performed in the raw 2D data instead of the reconstructed 3D concentration map, showing greater accuracy when unmixing algorithms are applied in the reconstructed data. Both the reflection and transmission geometries are considered.
Optical tomography multispectral imaging in vivo imaging fluorescence quantification Journal of Innovative Optical Health Sciences
2009, 2(4): 353–364
