REGULARIZATION FOR INVERTING THE RADON TRANSFORM WITH WEDGE CONSIDERATION By I. Aganj,

In limited angle tomography, with applications such as electron microscopy, medical imaging, and industrial testing, the object of interest is scanned over a limited angular range, which is less than the full 180◦ mathematically required for density reconstruction. The use of standard full-range reconstruction algorithms produces results with notorious “butterfly” or “wedge” artifacts. In this work we propose a reconstruction technique with a regularization term that takes into account the orientation of the missing angular range, also denoted as missing wedge. We show that a regularization that penalizes non-uniformly in the orientation space produces reconstructions with less artifacts, thereby improving the recovery of the “invisible” edges due to the missing wedge. We present the underlying framework and results for a challenging phantom and real cryo-electron microscopy data.