(a, b, and c) 2D and (d, e, and f) 3D simulated images showing the ground truth (a, d), and images with of 25% (b, e) and 50% (c, f). White and black surfaces (e, f) represent, respectively, voxels added to or missing from the ground truth. In 2D, the ground truth was an ellipse geometry of radius 1 AU (arbitrary units) along the x-axis and 0.5 AU along the y-axis, consisting of eight control points, located at constantly separated angles, between which the ellipse was interpolated with cubic splines. We then mapped this geometry on a grid of 256 × 256 pixels between −1.5 and 1.5 AU along both the x- and y-axes. In 3D, the ground-truth image was an ellipsoid geometry of radius 1 AU along the x-axis and 0.5 AU along both the y- and z-axes, consisting of 26 control points. See text for construction details. The geometry was mapped in a grid of 64 × 64 × 64 voxels between −1.5 and 1.5 AU along each of the three axes.
