**3.3 From the measured data to the surfaces**

DCT characterization of a polycrystalline aggregate results in voxel-based data. Voxel-based data is also obtained in other experimental techniques like computed tomography (CT) or magnetic resonance imaging (MRI). To obtain the shapes of individual grains their surfaces need to be reconstructed from the voxel-based data.

### **3.3.1 Treatment of holes**

The original DCT data contains 'holes' in the reconstructed grains, see the left-hand-side of Fig. 6. These are typical artifacts due to the limited number of projections available for each grain and the presence of erroneous contrast (Johnson et al., 2008; Ludwig et al., 2008). Since the holes are not expected in the experimental data, a simple and efficient treatment algorithm can be used to fill the holes by grain growth:


The right-hand-side of Fig. 6 displays wire data-set after the treatment above.
