Simulated subtomograms from phantom model. (a) Density map of an unsymmetric phantom model consisting of four different 3D Gaussian functions. This density map is used to simulate subtomograms of 323 voxels. (b) A slice of the reconstructed tomograms at different levels of noise (∞, 1, 0.5, 0.1), and different tilt angle ranges leading to different levels of missing wedge distortions. The isosurface are generated using the Chimera software package . The slices are plotted using MATLAB.