Improving Diffusion Models for Inverse Problems Using Optimal Posterior Covariance
On the map: Diffusion models → Inverse problems and image restoration
Abstract (arXiv)
Recent diffusion models provide a promising zero-shot solution to noisy linear inverse problems without retraining for specific inverse problems. In this paper, we reveal that recent methods can be uniformly interpreted as employing a Gaussian approximation with hand-crafted isotropic covariance for the intractable denoising posterior to approximate the conditional posterior mean. Inspired by this finding, we propose to improve recent methods by using more principled covariance determined by maximum likelihood estimation. To achieve posterior covariance optimization without retraining, we provide general plug-and-play solutions based on two approaches specifically designed for leveraging pre-trained models with and without reverse covariance. We further propose a scalable method for learning posterior covariance prediction based on representation with orthonormal basis. Experimental results demonstrate that the proposed methods significantly enhance reconstruction performance without requiring hyperparameter tuning.
Key facts. Cited by 42 papers in the map (data through 7 Oct 2026). Placed in Inverse problems and image restoration, one of 14 directions in Diffusion models. Builds on 35 of its 44 references that are in the map. First posted on arXiv 3 Feb 2024.
Builds on
35 of 44 references.
Closest ancestors · 9
Same direction, newest first
- 2023Beyond First-Order Tweedie: Solving Inverse Problems using Latent Diffusion1 Dec
- 2023Denoising Diffusion Models for Plug-and-Play Image Restoration15 May
- 2023A Variational Perspective on Solving Inverse Problems with Diffusion Models7 May
- 2023Score-Based Diffusion Models as Principled Priors for Inverse Imaging23 Apr
- 2023Refusion: Enabling Large-Size Realistic Image Restoration with Latent-Space Diffusion Models17 Apr
- 2023SUD2: Supervision by Denoising Diffusion Models for Image Reconstruction16 Mar
- 2022Zero-Shot Image Restoration Using Denoising Diffusion Null-Space Model1 Dec
- 2022Diffusion Posterior Sampling for General Noisy Inverse Problems29 Sep
- 2021Deblurring via Stochastic Refinement5 Dec
Other references · 26
- 2020Denoising Diffusion Probabilistic Modelscited by 20,851
- 2018The Unreasonable Effectiveness of Deep Features as a Perceptual Metriccited by 11,029
- 2020Denoising Diffusion Implicit Modelscited by 9,655
- 2020Score-Based Generative Modeling through Stochastic Differential Equationscited by 8,964
- 2021Diffusion Models Beat GANs on Image Synthesiscited by 8,185
- 2015Deep Unsupervised Learning using Nonequilibrium Thermodynamicscited by 7,005
- 2019Generative Modeling by Estimating Gradients of the Data Distributioncited by 4,067
- 2021Improved Denoising Diffusion Probabilistic Modelscited by 3,736
- 2022Elucidating the Design Space of Diffusion-Based Generative Modelscited by 2,994
- 2021Image Super-Resolution via Iterative Refinementcited by 1,506
- 2021Variational Diffusion Modelscited by 1,145
- 2021ILVR: Conditioning Method for Denoising Diffusion Probabilistic Modelscited by 634
14 more
- 2021Tackling the Generative Learning Trilemma with Denoising Diffusion GANscited by 515
- 2021Solving Inverse Problems in Medical Imaging with Score-Based Generative Modelscited by 514
- 2022Analytic-DPM: an Analytic Estimate of the Optimal Reverse Variance in Diffusion Probabilistic Modelscited by 331
- 2020Deep Unfolding Network for Image Super-Resolutioncited by 253
- 2020Nonlinear Transform Codingcited by 132
- 2018Taming VAEscited by 85
- 2022Estimating the Optimal Covariance with Imperfect Mean in Diffusion Probabilistic Modelscited by 83
- 2022Maximum Likelihood Training for Score-Based Diffusion ODEs by High-Order Denoising Score Matchingcited by 79
- 2023Training-free Linear Image Inverses via Flowscited by 70
- 2021Estimating High Order Gradients of the Data Distribution by Denoisingcited by 63
- 2023Frequency-Aware Transformer for Learned Image Compressioncited by 56
- 2023A Theoretical Justification for Image Inpainting using Denoising Diffusion Probabilistic Modelscited by 37
- 2018Structured Uncertainty Prediction Networkscited by 34
- 2023Uncertainty Quantification via Neural Posterior Principal Componentscited by 16
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Citing papers per year: 2024: 13; 2025: 14; 2026: 15.
42 papers.
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- 2024Taming Rectified Flow for Inversion and Editingcited by 200
- 2024Learning Diffusion Priors from Observations by Expectation Maximizationcited by 60
- 2024Steering Rectified Flow Models in the Vector Field for Controlled Image Generationcited by 38
- 2024Ensemble Kalman Diffusion Guidance: A Derivative-free Method for Inverse Problemscited by 18
- 2025Diffusion models for inverse problemscited by 15
- 2024Diffusion State-Guided Projected Gradient for Inverse Problemscited by 14
- 2024Free Hunch: Denoiser Covariance Estimation for Diffusion Models Without Extra Costscited by 14
- 2025IRBridge: Solving Image Restoration Bridge with Pre-trained Generative Diffusion Modelscited by 11
- 2024Inverse Problems with Diffusion Models: A MAP Estimation Perspectivecited by 9
- 2024Patch-Based Diffusion Models Beat Whole-Image Models for Mismatched Distribution Inverse Problemscited by 8
- 2024Equivariant Denoisers Cannot Copy Graphs: Align Your Graph Diffusion Modelscited by 7
- 2024Amortized Posterior Sampling with Diffusion Prior Distillationcited by 6
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- 2026DM4CT: Benchmarking Diffusion Models for Computed Tomography Reconstructioncited by 3
- 2026Sample-efficient evidence estimation of score based priors for model selectioncited by 3
- 2024Bayesian Conditioned Diffusion Models for Inverse Problemscited by 2
- 2024Enhancing Diffusion Posterior Sampling for Inverse Problems by Integrating Crafted Measurementscited by 2
- 2025Conditional Mutual Information Based Diffusion Posterior Sampling for Solving Inverse Problemscited by 2
- 2025Latent Refinement via Flow Matching for Training-free Linear Inverse Problem Solvingcited by 2
- 2026Image Restoration via Diffusion Models with Dynamic Resolutioncited by 2
- 2025MAP-based Problem-Agnostic diffusion model for Inverse Problemscited by 1
- 2025EquiReg: Equivariance Regularized Diffusion for Inverse Problemscited by 1
- 2025Noise Conditional Variational Score Distillationcited by 1
- 2025Diffusion models for multivariate subsurface generation and efficient probabilistic inversioncited by 1
- 2025Inverse problems with diffusion models: MAP estimation via mode-seeking losscited by 1
- 2026Taming Score-Based Denoisers in ADMM: A Convergent Plug-and-Play Frameworkcited by 1
- 2026Covariance-aware sampling for Diffusion Modelscited by 1
- 2025Decomposing stimulus-specific sensory neural information via diffusion modelscited by 0
- 2025Jacobian-Aware Posterior Sampling for Inverse Problemscited by 0
- 2025Softly Constrained Denoisers for Diffusion Models Applied to Partial Differential Equationscited by 0
- 2026Tracing the Oracle: Improving Diffusion Timestep Scheduling for 3D CT Reconstructioncited by 0
- 2026Stochastic Optimal Control Sampling for Diffusion Inverse Problemscited by 0
- 2026Concept Removal Guidance: Evidence-Calibrated Negative Guidance for Safe Diffusion Samplingcited by 0
- 2026Constrained Flow Matching via Lagrangian Dual Flowscited by 0
- 2026Posterior Information Dynamics of Diffusion Models for Linear Inverse Problemscited by 0
- 2026Direct Conditional Transition Sampling for Diffusion Inverse Problemscited by 0
- 2026Backward SDEs-based Diffusion for Physics-Constrained Generationcited by 0
- 2026ANaLOG: Anisotropic Native-Latent Operator Guidance for Solving Inverse Problemscited by 0
- 2026AECSF: Adaptive Ensemble Conditional Score Filtering for High-Dimensional Nonlinear Data Assimilationcited by 0
- 2026Is your uncertainty map wrong, or is its target? Exact diagnostics for the Tweedie diagonal, and a gradient-free alternativecited by 0
- 2026Is your uncertainty map wrong, or is its target? Exact diagnostics for the Tweedie diagonal, and a gradient-free alternative27 Sep 2026
- 2026AECSF: Adaptive Ensemble Conditional Score Filtering for High-Dimensional Nonlinear Data Assimilation26 Sep 2026
- 2026ANaLOG: Anisotropic Native-Latent Operator Guidance for Solving Inverse Problems25 Sep 2026
- 2026Backward SDEs-based Diffusion for Physics-Constrained Generation14 Sep 2026
- 2026Direct Conditional Transition Sampling for Diffusion Inverse Problems13 Sep 2026
- 2026Posterior Information Dynamics of Diffusion Models for Linear Inverse Problems22 Aug 2026
- 2026Constrained Flow Matching via Lagrangian Dual Flows5 Jul 2026
- 2026Concept Removal Guidance: Evidence-Calibrated Negative Guidance for Safe Diffusion Sampling29 Jun 2026
- 2026Stochastic Optimal Control Sampling for Diffusion Inverse Problems27 Jun 2026
- 2026Tracing the Oracle: Improving Diffusion Timestep Scheduling for 3D CT Reconstruction4 Jun 2026
- 2026Image Restoration via Diffusion Models with Dynamic Resolution14 May 2026
- 2026Covariance-aware sampling for Diffusion Models13 May 2026
30 more
- 2026Taming Score-Based Denoisers in ADMM: A Convergent Plug-and-Play Framework10 Mar 2026
- 2026Sample-efficient evidence estimation of score based priors for model selection24 Feb 2026
- 2026DM4CT: Benchmarking Diffusion Models for Computed Tomography Reconstruction20 Feb 2026
- 2025Softly Constrained Denoisers for Diffusion Models Applied to Partial Differential Equations17 Dec 2025
- 2025Inverse problems with diffusion models: MAP estimation via mode-seeking loss11 Dec 2025
- 2025Jacobian-Aware Posterior Sampling for Inverse Problems23 Nov 2025
- 2025Latent Refinement via Flow Matching for Training-free Linear Inverse Problem Solving8 Nov 2025
- 2025PriorGuide: Test-Time Prior Adaptation for Simulation-Based Inference15 Oct 2025
- 2025Diffusion models for inverse problems4 Aug 2025
- 2025Diffusion models for multivariate subsurface generation and efficient probabilistic inversion21 Jul 2025
- 2025Enhancing Diffusion Model Stability for Image Restoration via Gradient Management9 Jul 2025
- 2025Noise Conditional Variational Score Distillation11 Jun 2025
- 2025IRBridge: Solving Image Restoration Bridge with Pre-trained Generative Diffusion Models30 May 2025
- 2025EquiReg: Equivariance Regularized Diffusion for Inverse Problems29 May 2025
- 2025Decomposing stimulus-specific sensory neural information via diffusion models16 May 2025
- 2025MAP-based Problem-Agnostic diffusion model for Inverse Problems25 Jan 2025
- 2025Conditional Mutual Information Based Diffusion Posterior Sampling for Solving Inverse Problems6 Jan 2025
- 2024Steering Rectified Flow Models in the Vector Field for Controlled Image Generation27 Nov 2024
- 2024Enhancing Diffusion Posterior Sampling for Inverse Problems by Integrating Crafted Measurements15 Nov 2024
- 2024Taming Rectified Flow for Inversion and Editing7 Nov 2024
- 2024Patch-Based Diffusion Models Beat Whole-Image Models for Mismatched Distribution Inverse Problems15 Oct 2024
- 2024Free Hunch: Denoiser Covariance Estimation for Diffusion Models Without Extra Costs15 Oct 2024
- 2024Diffusion State-Guided Projected Gradient for Inverse Problems4 Oct 2024
- 2024Ensemble Kalman Diffusion Guidance: A Derivative-free Method for Inverse Problems30 Sep 2024
- 2024Gaussian is All You Need: A Unified Framework for Solving Inverse Problems via Diffusion Posterior Sampling13 Sep 2024
- 2024Inverse Problems with Diffusion Models: A MAP Estimation Perspective27 Jul 2024
- 2024Amortized Posterior Sampling with Diffusion Prior Distillation25 Jul 2024
- 2024Bayesian Conditioned Diffusion Models for Inverse Problems14 Jun 2024
- 2024Equivariant Denoisers Cannot Copy Graphs: Align Your Graph Diffusion Models27 May 2024
- 2024Learning Diffusion Priors from Observations by Expectation Maximization22 May 2024
- 2024Taming Rectified Flow for Inversion and Editingcited by 200
- 2024Learning Diffusion Priors from Observations by Expectation Maximizationcited by 60
- 2024Steering Rectified Flow Models in the Vector Field for Controlled Image Generationcited by 38
- 2024Ensemble Kalman Diffusion Guidance: A Derivative-free Method for Inverse Problemscited by 18
- 2025Diffusion models for inverse problemscited by 15
- 2024Diffusion State-Guided Projected Gradient for Inverse Problemscited by 14
- 2024Free Hunch: Denoiser Covariance Estimation for Diffusion Models Without Extra Costscited by 14
- 2025IRBridge: Solving Image Restoration Bridge with Pre-trained Generative Diffusion Modelscited by 11
- 2024Inverse Problems with Diffusion Models: A MAP Estimation Perspectivecited by 9
- 2024Patch-Based Diffusion Models Beat Whole-Image Models for Mismatched Distribution Inverse Problemscited by 8
- 2024Equivariant Denoisers Cannot Copy Graphs: Align Your Graph Diffusion Modelscited by 7
- 2024Amortized Posterior Sampling with Diffusion Prior Distillationcited by 6
12 most cited of 39 All 39 (JSON)
- 2026Is your uncertainty map wrong, or is its target? Exact diagnostics for the Tweedie diagonal, and a gradient-free alternative27 Sep 2026
- 2026ANaLOG: Anisotropic Native-Latent Operator Guidance for Solving Inverse Problems25 Sep 2026
- 2026Backward SDEs-based Diffusion for Physics-Constrained Generation14 Sep 2026
- 2026Posterior Information Dynamics of Diffusion Models for Linear Inverse Problems22 Aug 2026
- 2026Constrained Flow Matching via Lagrangian Dual Flows5 Jul 2026
- 2026Concept Removal Guidance: Evidence-Calibrated Negative Guidance for Safe Diffusion Sampling29 Jun 2026
- 2026Stochastic Optimal Control Sampling for Diffusion Inverse Problems27 Jun 2026
- 2026Tracing the Oracle: Improving Diffusion Timestep Scheduling for 3D CT Reconstruction4 Jun 2026
- 2026Image Restoration via Diffusion Models with Dynamic Resolution14 May 2026
- 2026Covariance-aware sampling for Diffusion Models13 May 2026
- 2026Taming Score-Based Denoisers in ADMM: A Convergent Plug-and-Play Framework10 Mar 2026
- 2026Sample-efficient evidence estimation of score based priors for model selection24 Feb 2026
12 newest of 39 All 39 (JSON)
- 2025Conditional Mutual Information Based Diffusion Posterior Sampling for Solving Inverse Problemscited by 2
- 2026Direct Conditional Transition Sampling for Diffusion Inverse Problemscited by 0
- 2026AECSF: Adaptive Ensemble Conditional Score Filtering for High-Dimensional Nonlinear Data Assimilationcited by 0
- 2026AECSF: Adaptive Ensemble Conditional Score Filtering for High-Dimensional Nonlinear Data Assimilation26 Sep 2026
- 2026Direct Conditional Transition Sampling for Diffusion Inverse Problems13 Sep 2026
- 2025Conditional Mutual Information Based Diffusion Posterior Sampling for Solving Inverse Problems6 Jan 2025
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