Signal and Noise Statistics Oblivious Sparse Reconstruction using OMP/OLS
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Orthogonal matching pursuit (OMP) and orthogonal least squares (OLS) are widely used for sparse signal reconstruction in under-determined linear regression problems. The performance of these compressed sensing (CS) algorithms depends crucially on the a priori knowledge of either the sparsity of the signal (k_0) or noise variance (σ^2). Both k_0 and σ^2 are unknown in general and extremely difficult to estimate in under determined models. This limits the application of OMP and OLS in many practical situations. In this article, we develop two computationally efficient frameworks namely TF-IGP and RRT-IGP for using OMP and OLS even when k_0 and σ^2 are unavailable. Both TF-IGP and RRT-IGP are analytically shown to accomplish successful sparse recovery under the same set of restricted isometry conditions on the design matrix required for OMP/OLS with a priori knowledge of k_0 and σ^2. Numerical simulations also indicate a highly competitive performance of TF-IGP and RRT-IGP in comparison to OMP/OLS with a priori knowledge of k_0 and σ^2.
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