Improved Support Recovery in Universal One-bit Compressed Sensing
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One-bit compressed sensing (1bCS) is an extremely quantized signal acquisition method that has been proposed and studied rigorously in the past decade. In 1bCS, linear samples of a high dimensional signal are quantized to only one bit per sample (sign of the measurement). Assuming the original signal vector to be sparse, existing results in 1bCS either aim to find the support of the vector, or approximate the signal allowing a small error. The focus of this paper is support recovery, which often also computationally facilitate approximate signal recovery. A universal measurement matrix for 1bCS refers to one set of measurements that work for all sparse signals. With universality, it is known that Θ̃(k^2) 1bCS measurements are necessary and sufficient for support recovery (where k denotes the sparsity). To improve the dependence on sparsity from quadratic to linear, in this work we propose approximate support recovery (allowing ϵ>0 proportion of errors), and superset recovery (allowing ϵ proportion of false positives). We show that the first type of recovery is possible with Õ(k/ϵ) measurements, while the later type of recovery, more challenging, is possible with Õ(max{k/ϵ,k^3/2}) measurements. We also show that in both cases Ω(k/ϵ) measurements would be necessary for universal recovery. Improved results are possible if we consider universal recovery within a restricted class of signals, such as rational signals, or signals with bounded dynamic range. In both cases superset recovery is possible with only Õ(k/ϵ) measurements. Other results on universal but approximate support recovery are also provided in this paper. All of our main recovery algorithms are simple and polynomial-time.
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