A fifteen-tile tomographic micro-CT dataset of a panel painting "Cadmus sowing dragon's teeth" 1/3

Summary
This submission contains a fifteen-tile tomographic dataset of a panel painting and 15 postprocessed images used for dendrochronological measurements (see related datasets).The data is made available as part of [Domínguez-Delmás et al., 2021].

Apparatus
The dataset is acquired using the custom-built and highly flexible CT scanner, FleX-ray Laboratory, developed by TESCAN-XRE, located at CWI in Amsterdam. This apparatus consists of a cone-beam microfocus X-ray point source that projects polychromatic X-rays onto a 1944-by-1536 pixels, 14-bit, flat detector panel. Full details can be found in [Coban 2020].
 
Sample Information
The sample is panel painting Cadmus Sowing dragon's teeth. H 26.2cm x w 42.3cm [Rijksmuseum inventory number SK-A-4051,  https://www.rijksmuseum.nl/en/collection/SK-A-4051]. It was mounted on a foam base on the rotation stage, see [Domínguez-Delmás et al., 2021] for images.

Experimental Plan
The data in this submission was collected to facilitate measurements of the tree rings (dendrochronological research) in a cross-section. The panel was mounted in such a way that the desired cross section would be obtained in the vertical direction. A section of a few cm wide along the entire height was imaged slightly off centre of the painting, to avoid metal nails that had showed up in several projections. In total 15 tiled CT scans were collected, moving source and detector vertically by the same distance. Each tile consisted of 1600 projections, each an average of 2 projections with 300ms acquisition time.  We used tube settings 70 kV, 70 mA and a 0.1 cm thickness copper filter. Dark-field (closed-shutter), and 2 flat-field (open-shutter) images were taken for each tile after the acquisition with 100 averaged images of 300 ms acquisition time. Reconstructed image resolution was 37 µm.
All raw data (i.e. no corrections) is made available in .tif format. Postprocessing steps are described in the supplementary material of [Domínguez-Delmás et al., 2021].
 
List of Contents
The content of the submission is divided in three datasets, with in total 16 subfolders: Images, containing the 15 postprocessed images used for dendrochronological measurements and Tile1-Tile15, each containing the data from one of the tiled scans.
Each data folder contains:

• dark-field (or closed-shutter) image, di000000.tif,
• flat-field (or open-shutter) image after acquisition, io000000.tif,
• raw (unprocessed or uncorrected) projections, scan_*.tif,
• data settings XRE.txt, a text file with scanner metadata,
• metadata.toml, a text file with a summary of the scanner metadata

Additional Links
These datasets are produced by the Computational Imaging group at Centrum Wiskunde & Informatica (CI-CWI). For any relevant Python/MATLAB scripts for the FleX-ray datasets, we refer the reader to our group's GitHub page.

Contact Details
For more information or guidance in using these datasets, please get in touch with

• bossema [at] cwi.nl

 
Acknowledgments
We thank Petria Noble for providing us with the opportunity to scan this interesting object. We thank Erma Hermens , Moorea Hall-Aquitania and Marta Domínguez Delmás for bringing the object and research questions to our attention and inviting our collaboration on this research project.
The authors would like to acknowledge the funding from the Netherlands Organisation for Scientific Research (NWO), project numbers 341-60-001, 639.073.506 and 628.007.033 and Netherlands Institute for Conservation, Art and Science (NICAS).