Talk
in
Workshop: Solving inverse problems with deep networks: New architectures, theoretical foundations, and applications
Robust One-Bit Recovery via ReLU Generative Networks: Improved Statistical Rate and Global Landscape Analysis
Shuang Qiu · Xiaohan Wei · Zhuoran Yang
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Abstract
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2019 Talk
Abstract:
We study the robust one-bit compressed sensing problem whose goal is to design an algorithm that faithfully recovers any sparse target vector \emph{uniformly} from quantized noisy measurements. Under the assumption that the measurements are sub-Gaussian, to recover any -sparse ( ) \emph{uniformly} up to an error with high probability, the best known computationally tractable algorithm requires\footnote{Here, an algorithm is ``computationally tractable'' if it has provable convergence guarantees. The notation omits a logarithm factor of .} . In this paper, we consider a new framework for the one-bit sensing problem where the sparsity is implicitly enforced via mapping a low dimensional representation through a known -layer ReLU generative network . Such a framework poses low-dimensional priors on without a known basis. We propose to recover the target via an unconstrained empirical risk minimization (ERM) problem under a much weaker \emph{sub-exponential measurement assumption}. For such a problem, we establish a joint statistical and computational analysis. In particular, we prove that the ERM estimator in this new framework achieves an improved statistical rate of recovering any uniformly up to an error . Moreover, from the lens of computation, despite non-convexity, we prove that the objective of our ERM problem has no spurious stationary point, that is, any stationary point is equally good for recovering the true target up to scaling with a certain accuracy. Our analysis sheds some light on the possibility of inverting a deep generative model under partial and quantized measurements, complementing the recent success of using deep generative models for inverse problems.
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