12.1 How does computed tomography work?12.2 Segmentation by a threshold12.3 Typical operations on 3D images: Dilation, erosion, cavity fill, and Boolean12.3.1 Dilation12.3.2 Erosion12.3.3 Practical example: Denoising12.3.4 Boolean operations on voxel models12.3.5 A few other uses of dilation and erosion12.3.6 Section 12.3 summary12.4 Practical example: Image vectorization12.4.1 Input image12.4.2 Step 1: Obtain a contour12.4.3 Step 2: Fit the contour12.4.4 Step 3: Make the contour smooth12.4.5 Implementation12.4.6 Section 12.4 summary12.5 How voxels, triangles, parametric surfaces, and SDFs work together12.6 Exercises12.7 Solutions to exercisesSummary