1. A reconstruction method, comprising: acquiring a set of projection data from a plurality of views around an imaged volume; performing an iterative reconstruction of the set of projection data by solving an objective function comprising at least a dictionary-based term, wherein the dictionary-based term employs dictionary learning that employs two or more dictionaries each comprising at least some two-dimensional image patches oriented in different directions; and generating a reconstructed image upon completion of the iterative reconstruction.
1. A reconstruction method, comprising: acquiring a set of projection data from a plurality of views around an imaged volume; performing an iterative reconstruction of the set of projection data by solving an objective function comprising at least a dictionary-based term, wherein the dictionary-based term employs dictionary learning that employs two or more dictionaries each comprising at least some two-dimensional image patches oriented in different directions; and generating a reconstructed image upon completion of the iterative reconstruction. 3. The method of claim 1 , wherein the two or more dictionaries comprises three dictionaries, wherein each dictionary comprises two-dimensional image patches corresponding to a different orthogonal direction.