A Comparative Study of MAP and LMMSE Estimators for Blind Inverse Problems

Fuente: arXiv
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Autores principales: Buskulic, Nathan, Calatroni, Luca
Formato: Preprint
Publicado: 2026
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author Buskulic, Nathan
Calatroni, Luca
author_facet Buskulic, Nathan
Calatroni, Luca
contents Maximum-a-posteriori (MAP) approaches are an effective framework for inverse problems with known forward operators, particularly when combined with expressive priors and careful parameter selection. In blind settings, however, their use becomes significantly less stable due to the inherent non-convexity of the problem and the potential non-identifiability of the solutions. (Linear) minimum mean square error (MMSE) estimators provide a compelling alternative that can circumvent these limitations. In this work, we study synthetic two-dimensional blind deconvolution problems under fully controlled conditions, with complete prior knowledge of both the signal and kernel distributions. We compare tailored MAP algorithms with simple LMMSE estimators whose functional form is closely related to that of an optimal Tikhonov estimator. Our results show that, even in these highly controlled settings, MAP methods remain unstable and require extensive parameter tuning, whereas the LMMSE estimator yields a robust and reliable baseline. Moreover, we demonstrate empirically that the LMMSE solution can serve as an effective initialization for MAP approaches, improving their performance and reducing sensitivity to regularization parameters, thereby opening the door to future theoretical and practical developments.
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id arxiv_https___arxiv_org_abs_2602_11814
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publishDate 2026
record_format arxiv
spellingShingle A Comparative Study of MAP and LMMSE Estimators for Blind Inverse Problems
Buskulic, Nathan
Calatroni, Luca
Information Theory
Computer Vision and Pattern Recognition
Machine Learning
Maximum-a-posteriori (MAP) approaches are an effective framework for inverse problems with known forward operators, particularly when combined with expressive priors and careful parameter selection. In blind settings, however, their use becomes significantly less stable due to the inherent non-convexity of the problem and the potential non-identifiability of the solutions. (Linear) minimum mean square error (MMSE) estimators provide a compelling alternative that can circumvent these limitations. In this work, we study synthetic two-dimensional blind deconvolution problems under fully controlled conditions, with complete prior knowledge of both the signal and kernel distributions. We compare tailored MAP algorithms with simple LMMSE estimators whose functional form is closely related to that of an optimal Tikhonov estimator. Our results show that, even in these highly controlled settings, MAP methods remain unstable and require extensive parameter tuning, whereas the LMMSE estimator yields a robust and reliable baseline. Moreover, we demonstrate empirically that the LMMSE solution can serve as an effective initialization for MAP approaches, improving their performance and reducing sensitivity to regularization parameters, thereby opening the door to future theoretical and practical developments.
title A Comparative Study of MAP and LMMSE Estimators for Blind Inverse Problems
topic Information Theory
Computer Vision and Pattern Recognition
Machine Learning
url https://arxiv.org/abs/2602.11814