COMBINED 3D AND MULTISPECTRAL FRESCO DOCUMENTATION OF THE VILLA OPLONTIS, POMPEI High-Resolution and High-Performance Digitization of Cultural Heritage

摘要

Motivated by cultural heritage, industry, medicine we are developing 3D-scanners and post-processing systems for rapid and precise documentation of surfaces with curvature. By constantly increasing resolution and accuracy of our system we can enable the documentation of small deviations of even flat surfaces - like frescos. This enables documentation of important features for restoration like small fractures or topology of paintstrokes for scientific research. The 3D-documentation can be done in-situ, radiation-free and contact-free using a structured (coded) light-source and a digital camera. Using light for documentation of colourful painted surface lead to the integration of colour-filtering techniques to "see thru" the first layer(s) of paint. This approach, typically known from photography, is used to reveal under- drawings of paintings. While photographs suffer from lens distortion lacking a precise scale, we can provide the height of paint-layers in μm in a properly calibrated scale. This method has already been successful tested on synthetic data and medieval paintings and statues, which cover not all painting techniques known to art historians. Therefore we conducted experiments in Pompei to determine the capabilities of our system for fresco paintings. Results shown in this report cover traditional close-range 3D-acquisition for larger fields of view (m~2) and multi-spectral 3D-acquisition for paint layers having a field of view of ≈ 600cm~2. Regarding performance - having a tremendous amount of frescos - we could show that 3D-acquisition can be done in ≈ 15 minutes per m~2. Multi-spectral 3D-acquisition can be applied in a similar fast manner by using expert-knowledge to narrow down the areas of interest.