Abstract
To exploit the advantageous properties of isogeometric analysis (IGA) in a scan-based setting, it is important to extract a smooth geometric domain from the scan data (e.g., voxel data). IGA-suitable domains can be constructed by convoluting the grayscale data using B-splines. A negative side-effect of this convolution technique is, however, that it can induce topological changes in the process of smoothing when features with a size similar to that of the voxels are encountered. This manuscript presents an enhanced B-spline-based segmentation procedure using a refinement strategy based on truncated hierarchical (TH)B-splines. A Fourier analysis is presented to explain the effectiveness of local grayscale function refinement in repairing topological anomalies. A moving-window-based topological anomaly detection algorithm is proposed to identify regions in which the grayscale function refinements must be performed. The criterion to identify topological anomalies is based on the Euler characteristic, giving it the capability to distinguish between topological and shape changes. The proposed topology-preserving THB-spline image segmentation strategy is studied using a range of test cases. These tests pertain to both the segmentation procedure itself, and its application in an immersed IGA setting.
Original language | English |
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Article number | 114648 |
Number of pages | 34 |
Journal | Computer Methods in Applied Mechanics and Engineering |
Volume | 392 |
DOIs | |
Publication status | Published - 15 Mar 2022 |
Funding
We acknowledge the support from the European Commission EACEA Agency, Framework Partnership Agreement 2013–0043 Erasmus Mundus Action 1b , as a part of the EM Joint Doctorate Simulation in Engineering and Entrepreneurship Development (SEED). A.R. acknowledges the partial support of the MIUR-PRIN project XFAST-SIMS, Italy (no. 20173C478N ). All the simulations in this work were performed based on the open source software package Nutils ( www.nutils.org ) [113] . We acknowledge the support of the Nutils team, Netherlands . We acknowledge Michele Conti for providing the CT-scan data of the stenotic carotid and Alice Finotello for the help in understanding the data. The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: E.H. van Brummelen reports financial support was provided by European Commission. A Reali reports financial support.
Keywords
- Finite Cell Method (FCM)
- Image filtering
- Isogeometric analysis (IGA)
- Scan-based analysis
- Topology detection