3D Modelling of raw diamonds from micro-CT data
The city of Antwerp can be considered the heart of the world diamond trading business. Raw diamonds, obtained in mines throughout the world, are transported to Antwerp for high precision cutting and, of course, selling. Cutting raw diamonds is a nontrivial task. First, one needs to determine in what shape, or shapes, the diamond will be cut, possibly even splitting it into several parts. Then a precise map of the diamond must be made to guide the actual cutting procedure. Determining the exact shape of the raw diamond is crucial to creating as much value as possible in the final product. The ASTRA research group collaborates with a company called Diamcad, which performs X-ray CT-scans of raw diamonds to create 3D models of their shapes. Such models can then be used for automatic shape optimization. In our reconstruction algorithms, we exploit the knowledge that diamonds are rather homogeneous objects in order to obtain more accurate reconstructions, from fewer X-ray images. Recently, we faced an urgent problem: a diamond was scanned that was too large for the scanner. The individual X-ray photos were too small to contain the whole diamond. In medical CT, this problem is known as truncation. In general, an object simply cannot be reconstructed from its truncated X-ray projections. By using prior knowledge, we are able to reconstruct the whole diamond accurately, despite the truncation. Before FASTRA, reconstructing the complete diamond (1024x1024x1024 voxels) would have taken us several weeks. Now, it can be done on a our desktop supercomputer within hours.
Analysis of bone for osteoporosis research
We work with scientists and companies that perform research on bone diseases, such as osteoporosis. Scans of bone from mice, obtained by X-ray micro-tomography provide important information for the development of new medicines. By using prior knowledge, we are able to reconstruct the bone structure from far fewer X-ray photos, resulting in a lower radiation dose for the mouse being scanned. FASTRA allows us to perform these reconstructions in reasonable time.
3D Imaging at the nanoscale: electron tomography
Electron tomography is a powerful tool for three-dimensional imaging at the nano-scale. Instead of an X-ray setup, an electron microscope is used to acquire a series of projection images of a nano-sample, from a range of angles. In collaboration with EMAT, the Institute of Electron Microscopy for Materials Science, we are developing new methods for 3D imaging of nanomaterials.
On the left you see a series of projection images of a carbon nanotube, recorded by an electron microscope. The nanotube has a diameter of less than 100nm. By using our advanced reconstruction algorithms, we are able to create a very good 3-dimensional reconstruction (image on the right). Using conventional reconstruction techniques, computing such an image was simply not possible.