Compressed sensing under matrix uncertainty: Optimum thresholds and robust approximate message passing

In compressed sensing one measures sparse signals directly in a compressed form via a linear transform and then reconstructs the original signal. However, it is often the case that the linear transform itself is known only approximately, a situation called matrix uncertainty, and that the measurement process is noisy. Here we present two contributions to this problem: first, we use the replica method to determine the mean-squared error of the Bayes-optimal reconstruction of sparse signals under matrix uncertainty. Second, we consider a robust variant of the approximate message passing algorithm and demonstrate numerically that in the limit of large systems, this algorithm matches the optimal performance in a large region of parameters.