Development and characterization of a portable CT system for wooden sculptures analysis

Abstract

In this work, a portable computed tomography (CT) system was developed and applied for the analysis of wooden sculptures. The CT system is composed by a portable 120 kV X-ray tube and a 410 × 410 mm a-Si flat panel detector with a pixel size of 200 μm. An arduino controlled rotary table was used for the angular movement of the part under analysis. A wooden piece was used for the characterization of the system and the CT images were compared with the ones acquired with a microCT equipment. This piece is a 300 × 160 × 90 mm (H x W x D) wooden block with several details that can be found in wooden sculptures, as thickness reductions, cracks, metallic inclusions, assembling of different wooden parts etc. After the characterization, the system was used for the analysis of a 380 mm high wooden sculpture and the images were also compared with the microCT ones. After these steps, the system was applied for the on-site analysis of the head of a 1100 mm high sculpture. The images acquired with the portable CT system showed to be similar when compared with the microCT equipment. Also, other characteristics of the piece were perfectly visualized, like growth rings, damages caused by xylophagous insects and assembling of different woods. The statue analysis revealed their structural conditions and their manufacturing process, as the types of glass eyes and the different wood densities used. The results showed that the portable CT system can be used for on-site investigation of wooden statues that can't be moved for in-lab evaluations, with qualitative and quantitative results equivalent to the microCT.