How to Trust Your Diffusion Model: A Convex Optimization Approach to Conformal Risk Control (2302.03791v3)
Abstract: Score-based generative modeling, informally referred to as diffusion models, continue to grow in popularity across several important domains and tasks. While they provide high-quality and diverse samples from empirical distributions, important questions remain on the reliability and trustworthiness of these sampling procedures for their responsible use in critical scenarios. Conformal prediction is a modern tool to construct finite-sample, distribution-free uncertainty guarantees for any black-box predictor. In this work, we focus on image-to-image regression tasks and we present a generalization of the Risk-Controlling Prediction Sets (RCPS) procedure, that we term $K$-RCPS, which allows to $(i)$ provide entrywise calibrated intervals for future samples of any diffusion model, and $(ii)$ control a certain notion of risk with respect to a ground truth image with minimal mean interval length. Differently from existing conformal risk control procedures, ours relies on a novel convex optimization approach that allows for multidimensional risk control while provably minimizing the mean interval length. We illustrate our approach on two real-world image denoising problems: on natural images of faces as well as on computed tomography (CT) scans of the abdomen, demonstrating state of the art performance.
- A rewriting system for convex optimization problems. Journal of Control and Decision, 5(1):42–60, 2018.
- Brian DO Anderson. Reverse-time diffusion equation models. Stochastic Processes and their Applications, 12(3):313–326, 1982.
- A gentle introduction to conformal prediction and distribution-free uncertainty quantification. arXiv preprint arXiv:2107.07511, 2021.
- Learn then test: Calibrating predictive algorithms to achieve risk control. arXiv preprint arXiv:2110.01052, 2021.
- Conformal risk control. arXiv preprint arXiv:2208.02814, 2022a.
- Image-to-image regression with distribution-free uncertainty quantification and applications in imaging. In International Conference on Machine Learning, pages 717–730. PMLR, 2022b.
- MOSEK ApS. The MOSEK optimization toolbox for MATLAB manual. Version 9.0., 2019. URL http://docs.mosek.com/9.0/toolbox/index.html.
- Predictive inference with the jackknife+. The Annals of Statistics, 49(1):486–507, 2021.
- Conformal prediction beyond exchangeability. arXiv preprint arXiv:2202.13415, 2022.
- Distribution-free, risk-controlling prediction sets. Journal of the ACM (JACM), 68(6):1–34, 2021.
- Vidmantas Bentkus. On hoeffding’s inequalities. The Annals of Probability, 32(2):1650–1673, 2004.
- Pattern recognition and machine learning, volume 4. Springer, 2006.
- Vector quantile regression: an optimal transport approach. The Annals of Statistics, 44(3):1165–1192, 2016.
- Vector quantile regression and optimal transport, from theory to numerics. Empirical Economics, pages 1–28, 2020.
- Monge–kantorovich depth, quantiles, ranks and signs. The Annals of Statistics, 45(1):223–256, 2017.
- Diffdock: Diffusion steps, twists, and turns for molecular docking. arXiv preprint arXiv:2210.01776, 2022.
- Diffusion models in vision: A survey. arXiv preprint arXiv:2209.04747, 2022.
- Diffusion models in vision: A survey. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2023.
- CVXPY: A Python-embedded modeling language for convex optimization. Journal of Machine Learning Research, 17(83):1–5, 2016.
- Dropout as a bayesian approximation: Representing model uncertainty in deep learning. In international conference on machine learning, pages 1050–1059. PMLR, 2016.
- Stochastic optimization for large-scale optimal transport. Advances in neural information processing systems, 29, 2016.
- Nested conformal prediction and quantile out-of-bag ensemble methods. Pattern Recognition, 127:108496, 2022.
- Denoising diffusion probabilistic models. Advances in Neural Information Processing Systems, 33:6840–6851, 2020.
- Wassily Hoeffding. Probability inequalities for sums of bounded random variables. In The collected works of Wassily Hoeffding, pages 409–426. Springer, 1994.
- Equivariant diffusion for molecule generation in 3d. In International Conference on Machine Learning, pages 8867–8887. PMLR, 2022.
- Conffusion: Confidence intervals for diffusion models. arXiv preprint arXiv:2211.09795, 2022.
- Estimation of non-normalized statistical models by score matching. Journal of Machine Learning Research, 6(4), 2005.
- Illuminating protein space with a programmable generative model. bioRxiv, 2022.
- Stochastic solutions for linear inverse problems using the prior implicit in a denoiser. Advances in Neural Information Processing Systems, 34:13242–13254, 2021.
- Brownian motion and stochastic calculus, volume 113. Springer Science & Business Media, 1991.
- Snips: Solving noisy inverse problems stochastically. Advances in Neural Information Processing Systems, 34:21757–21769, 2021a.
- Stochastic image denoising by sampling from the posterior distribution. In Proceedings of the IEEE/CVF International Conference on Computer Vision, pages 1866–1875, 2021b.
- Diffusion models for medical image analysis: A comprehensive survey. arXiv preprint arXiv:2211.07804, 2022.
- Regression quantiles. Econometrica: journal of the Econometric Society, pages 33–50, 1978.
- What’s behind the mask: Estimating uncertainty in image-to-image problems. arXiv preprint arXiv:2211.15211, 2022.
- Efficiently controlling multiple risks with pareto testing. arXiv preprint arXiv:2210.07913, 2022.
- Convergence for score-based generative modeling with polynomial complexity. arXiv preprint arXiv:2206.06227, 2022.
- Distribution-free prediction bands for non-parametric regression. Journal of the Royal Statistical Society: Series B (Statistical Methodology), 76(1):71–96, 2014.
- A kernelized stein discrepancy for goodness-of-fit tests. In International conference on machine learning, pages 276–284. PMLR, 2016.
- Large-scale celebfaces attributes (celeba) dataset. Retrieved August, 15(2018):11, 2018.
- Abdomenct-1k: Is abdominal organ segmentation a solved problem. IEEE Transactions on Pattern Analysis and Machine Intelligence, 2021.
- Latent-nerf for shape-guided generation of 3d shapes and textures. arXiv preprint arXiv:2211.07600, 2022.
- Efficient learning of generative models via finite-difference score matching. Advances in Neural Information Processing Systems, 33:19175–19188, 2020.
- Inductive confidence machines for regression. In European Conference on Machine Learning, pages 345–356. Springer, 2002.
- Conformalized quantile regression. Advances in neural information processing systems, 32, 2019.
- U-net: Convolutional networks for biomedical image segmentation. In International Conference on Medical image computing and computer-assisted intervention, pages 234–241. Springer, 2015.
- Fast nonlinear vector quantile regression. arXiv preprint arXiv:2205.14977, 2022.
- A tutorial on conformal prediction. Journal of Machine Learning Research, 9(3), 2008.
- Deep unsupervised learning using nonequilibrium thermodynamics. In International Conference on Machine Learning, pages 2256–2265. PMLR, 2015.
- Generative modeling by estimating gradients of the data distribution. Advances in Neural Information Processing Systems, 32, 2019.
- Improved techniques for training score-based generative models. Advances in neural information processing systems, 33:12438–12448, 2020.
- Sliced score matching: A scalable approach to density and score estimation. In Uncertainty in Artificial Intelligence, pages 574–584. PMLR, 2020a.
- Score-based generative modeling through stochastic differential equations. arXiv preprint arXiv:2011.13456, 2020b.
- Solving inverse problems in medical imaging with score-based generative models. arXiv preprint arXiv:2111.08005, 2021.
- Towards a most probable recovery in optical imaging. arXiv preprint arXiv:2212.03235, 2022.
- Vladimir Vovk. Cross-conformal predictors. Annals of Mathematics and Artificial Intelligence, 74(1):9–28, 2015.
- Algorithmic learning in a random world. Springer Science & Business Media, 2005.
- Broadly applicable and accurate protein design by integrating structure prediction networks and diffusion generative models. bioRxiv, 2022.
- Measurement-conditioned denoising diffusion probabilistic model for under-sampled medical image reconstruction. arXiv preprint arXiv:2203.03623, 2022.
- Dream3d: Zero-shot text-to-3d synthesis using 3d shape prior and text-to-image diffusion models. arXiv preprint arXiv:2212.14704, 2022.
- Diffusion models: A comprehensive survey of methods and applications. arXiv preprint arXiv:2209.00796, 2022.
- Lion: Latent point diffusion models for 3d shape generation. arXiv preprint arXiv:2210.06978, 2022.