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arXiv · 2603.01860

Multiresolution Adaptive Block-Coordinate Forward-Backward for Image Reconstruction

Edgar Desainte-Maréville·Marion Foare·Paulo Gonçalves·Nelly Pustelnik·Elisa Riccietti
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Abstract

Classical first-order optimization methods for imaging inverse problems scale poorly with image resolution. Wavelet based multilevel strategies can accelerate convergence under strong blur, but their fixed coarse-to-fine schedules lose effectiveness in moderate-blur or noise-dominated regimes. In this work, we propose an adaptive multiresolution block coordinate Forward-Backward algorithm for image restoration. Multiresolution block selection is driven by the local magnitude of the proximal update via a stochastic non-smooth Gauss-Southwell rule applied to the wavelet decomposition of the image. This adaptive selection strategy dynamically balances updates across scales, emphasizing coarse or fine blocks according to the degradation regime. As a result, the proposed method automatically adapts to varying blur and noise levels without relying on a predefined hierarchical update scheme.

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Edgar Desainte-Maréville, Marion Foare, Paulo Gonçalves, Nelly Pustelnik, Elisa Riccietti. 2026-03-02. Multiresolution Adaptive Block-Coordinate Forward-Backward for Image Reconstruction. https://arxiv.org/abs/2603.01860

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