In this paper, we study the problem of recovering two unknown signals from their convolution, which is commonly referred to as blind deconvolution. Reformulation of blind deconvolution as a low-rank recovery problem has led to multiple theoretical recovery guarantees in the past decade due to the success of the nuclear norm minimization heuristic. In particular, in the absence of noise, exact recovery has been established for sufficiently incoherent signals contained in lower-dimensional subspaces. However, if the convolution is corrupted by additive bounded noise, the stability of the recovery problem remains much less understood. In particular, existing reconstruction bounds involve large dimension factors and therefore fail to explain the empirical evidence for dimension-independent robustness of nuclear norm minimization. Recently, theoretical evidence has emerged for ill-posed behavior of low-rank matrix recovery for sufficiently small noise levels. In this work, we develop improved recovery guarantees for blind deconvolution with adversarial noise which exhibit square-root scaling in the noise level. Hence, our results are consistent with existing counterexamples which speak against linear scaling in the noise level as demonstrated for related low-rank matrix recovery problems.
翻译:本文研究从卷积中恢复两个未知信号的问题,通常称为盲卷积。将盲卷积重新表述为低秩恢复问题已经在过去的十年中导致了多个理论恢复保证的出现,这得益于核范数最小化启发式方法的成功。特别地,在没有噪声的情况下,已经针对包含在低维子空间中的足够表示稀疏的信号建立了确切的恢复保证。然而,如果卷积受到添加有界噪声的污染, 恢复问题的稳定性仍然未得到广泛理解。特别是,现有的重构界限涉及大的维度因素,因此未能解释核范数最小化方法的维度无关鲁棒性的经验证据。最近, 已经出现了有关于足够小的噪声水平下低秩矩阵恢复问题将是不适定的理论证据。在本文中,我们开发了针对具有对抗性噪声盲卷积的改进恢复保证,展现了与噪声水平的平方根缩放一致的结果。因此,我们的结果与已有的反例一致,这些反例证明了相关的低秩矩阵恢复问题与噪声水平的线性缩放相矛盾。