DEFT: Efficient Fine-Tuning of Diffusion Models by Learning the Generalised $h$-transform

Fuente: arXiv
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Auteurs principaux: Denker, Alexander, Vargas, Francisco, Padhy, Shreyas, Didi, Kieran, Mathis, Simon, Dutordoir, Vincent, Barbano, Riccardo, Mathieu, Emile, Komorowska, Urszula Julia, Lio, Pietro
Format: Preprint
Publié: 2024
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author Denker, Alexander
Vargas, Francisco
Padhy, Shreyas
Didi, Kieran
Mathis, Simon
Dutordoir, Vincent
Barbano, Riccardo
Mathieu, Emile
Komorowska, Urszula Julia
Lio, Pietro
author_facet Denker, Alexander
Vargas, Francisco
Padhy, Shreyas
Didi, Kieran
Mathis, Simon
Dutordoir, Vincent
Barbano, Riccardo
Mathieu, Emile
Komorowska, Urszula Julia
Lio, Pietro
contents Generative modelling paradigms based on denoising diffusion processes have emerged as a leading candidate for conditional sampling in inverse problems. In many real-world applications, we often have access to large, expensively trained unconditional diffusion models, which we aim to exploit for improving conditional sampling. Most recent approaches are motivated heuristically and lack a unifying framework, obscuring connections between them. Further, they often suffer from issues such as being very sensitive to hyperparameters, being expensive to train or needing access to weights hidden behind a closed API. In this work, we unify conditional training and sampling using the mathematically well-understood Doob's h-transform. This new perspective allows us to unify many existing methods under a common umbrella. Under this framework, we propose DEFT (Doob's h-transform Efficient FineTuning), a new approach for conditional generation that simply fine-tunes a very small network to quickly learn the conditional $h$-transform, while keeping the larger unconditional network unchanged. DEFT is much faster than existing baselines while achieving state-of-the-art performance across a variety of linear and non-linear benchmarks. On image reconstruction tasks, we achieve speedups of up to 1.6$\times$, while having the best perceptual quality on natural images and reconstruction performance on medical images. Further, we also provide initial experiments on protein motif scaffolding and outperform reconstruction guidance methods.
format Preprint
id arxiv_https___arxiv_org_abs_2406_01781
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle DEFT: Efficient Fine-Tuning of Diffusion Models by Learning the Generalised $h$-transform
Denker, Alexander
Vargas, Francisco
Padhy, Shreyas
Didi, Kieran
Mathis, Simon
Dutordoir, Vincent
Barbano, Riccardo
Mathieu, Emile
Komorowska, Urszula Julia
Lio, Pietro
Machine Learning
Generative modelling paradigms based on denoising diffusion processes have emerged as a leading candidate for conditional sampling in inverse problems. In many real-world applications, we often have access to large, expensively trained unconditional diffusion models, which we aim to exploit for improving conditional sampling. Most recent approaches are motivated heuristically and lack a unifying framework, obscuring connections between them. Further, they often suffer from issues such as being very sensitive to hyperparameters, being expensive to train or needing access to weights hidden behind a closed API. In this work, we unify conditional training and sampling using the mathematically well-understood Doob's h-transform. This new perspective allows us to unify many existing methods under a common umbrella. Under this framework, we propose DEFT (Doob's h-transform Efficient FineTuning), a new approach for conditional generation that simply fine-tunes a very small network to quickly learn the conditional $h$-transform, while keeping the larger unconditional network unchanged. DEFT is much faster than existing baselines while achieving state-of-the-art performance across a variety of linear and non-linear benchmarks. On image reconstruction tasks, we achieve speedups of up to 1.6$\times$, while having the best perceptual quality on natural images and reconstruction performance on medical images. Further, we also provide initial experiments on protein motif scaffolding and outperform reconstruction guidance methods.
title DEFT: Efficient Fine-Tuning of Diffusion Models by Learning the Generalised $h$-transform
topic Machine Learning
url https://arxiv.org/abs/2406.01781