Amortized Inference for Heterogeneous Reconstruction in Cryo-EM

In a single particle cryo-electron microscopy (cryo-EM) experiment, an aqueous solution of purified biomolecules is flash-frozen in a thin layer of vitreous ice and imaged with a transmission electron microscope (Figure 1 (a)). A cryo-EM experiment outputs a large set of unlabeled images, each containing a 2D projection of a unique molecule, whose 3D structure is sampled from some thermodynamic distribution (i.e. a conformation) and viewed from an unknown orientation (i.e. a