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. 5. The method of claim 1 , wherein the two or more dictionaries comprise two or more direction specific dictionaries, wherein each direction specific dictionary comprises both two-dimensional image patches found in multiple directions and two-dimensional image patches present in only one direction specific to the direction-specific dictionary.