Iterative Alpha Expansion for Estimating Gradient-Sparse Signals from Linear Measurements

نویسندگان

چکیده

Abstract We consider estimating a piecewise-constant image, or gradient-sparse signal on general graph, from noisy linear measurements. propose and study an iterative algorithm to minimize penalized least-squares objective, with penalty given by the “ℓ0-norm” of signal’s discrete graph gradient. The method uses non-convex variant proximal gradient descent, applying alpha-expansion procedure approximate mapping in each iteration, using geometric decay parameter across iterations ensure convergence. Under cut-restricted isometry property for measurement design, we prove global recovery guarantees estimated signal. For standard Gaussian designs, required number measurements is independent structure, improves upon worst-case total-variation (TV) compressed sensing 1-D line 2-D lattice graphs polynomial logarithmic factors respectively. empirically yields lower mean-squared error compared TV regularization regimes moderate undersampling high signal-to-noise, several examples changepoint signals phantom images.

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ژورنال

عنوان ژورنال: Journal of The Royal Statistical Society Series B-statistical Methodology

سال: 2021

ISSN: ['1467-9868', '1369-7412']

DOI: https://doi.org/10.1111/rssb.12407