“…For instance, a wide range of recent methods introduce image sparsity as a prior model. These methods include Fienupstyle alternating projections [7], [8], [9], semidefinite programming via "matrix lifting" [10], [11], [12], [13], [14], [15], generalized approximate message passing [16], greedy pursuit [17], and variable splitting [18]. However, with the exception of semidefinite programming, these methods are restricted to synthesis-form or canonical sparsity.…”