| Interested in the mutual influence between root growth and soil compaction from a biomechanical perspective, this project analyzed the change in root morphology and packing fraction during root growth in a granular medium, using 3D X-ray computed tomography (CT) to visualize the system. Experiments for identifying the optimal parameters for X-ray CT measurement were carried out, providing a systematic method for finding suitable parameters in future experiments. The algorithm for detecting the particles’ positions and extracting the root surface from the tomogram was modified based on previous code in MATLAB. The particle detection algorithm is shown to have nice accuracy, while the root extracting algorithm needs further modification. Voro++ and Pomelo were used to conduct (Set-)Voronoi tessellation of the samples. Packing fractions of the particles and the roots were investigated, as well as the effect of sampling rate on Voronoi tessellation. The sample only with particles and gel has a local packing fraction distribution consistent with the theory. Due to the inaccuracy of the root extraction algorithm, the results for the sample with the root are not robust enough. Nevertheless, the workflow of both imaging and structural analysis can be applied to future data sets of CT scans. |
