Three tomographic CT datasets of a woven fabric

Summary
This submission contains three tomographic datasets of a fragment of fabric woven in tapestry weave. The data is collected at three different zoom levels to achieve different reconstructed image resolution.
The data is made available as part of [Bossema 2020].  

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 a fragment of woven fabric approximately 7cm x 15cm in size. The fabric was hung vertically on a piece of foam, held on the top by a wooden stick through one of the holes and on the bottom by a piece of plastic tape. See Figure 5 in [Bossema 2020] for a picture of the object and examples of the reconstruction. 
 

Experimental Plan
The data in this submission was collected to illustrate the use of zooming for the investigation of cultural heritage objects. Three region-of-interest scans of the lower part, containing a hole, were collected at different zoom levels. For each scan, the sample was rotated 360° in circular and continuous motion, with a dark-field (closed-shutter), and flat-field (open-shutter) image taken before the acquisition. Each dataset consists of 1200 projections. The source-detector distance was kept at 1098mm. At the first level of zooming, the object was placed at 963mm from the source yielding a magnification of 1.14 and 131 micron resolution. For the second level the object was moved closer to the source so that the source-object distance was 603mm, yielding a magnification of 1.82 and 82 micron resolution. At the third level, the source-object distance was reduced to 243, yielding a magnification of 4.5 and 33 micron resolution.
All raw data (i.e. no corrections) is made available in .tif format.

List of Contents

The content of the submission is given below.

• level1: lowest resolution scan.
• level2: higher resolution scan.
• level3: highest resolution scan.

Each data folder contains:

• dark-field (or closed-shutter) image, di000000.tif,
• flat-field (or open-shutter before acquisition) image, io000000.tif,
• raw (unprocessed or uncorrected) projections, scan_*.tif,
• data settings XRE.txt, a text file with scanner metadata,
• scan settings.txt, a text file with scanner metadata in a human readable format, and
• data settings XRE.ini, a snapshot text file of basic geometry information at the start of a scan.
• script_executed.txt, the text file containing the list of commands the apparatus has executed.

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 Suzan Meijer of the Rijksmuseum for providing this sample.