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Boosting Latent Diffusion with Flow Matching (arxiv.org)
1 point by lnyan on Feb 23, 2024 | hide | past | pdf | discuss on HN

In plain words: A small frozen diffusion model makes a diverse low-res image, then a fast straight-line generator (flow matching) expands it into a larger intermediate form that a decoder turns into a big photo. This reaches top-quality 1024×1024 images at low cost, and scales to 2048×2048.

Abstract

Visual synthesis has recently seen significant leaps in performance, largely due to breakthroughs in generative models. Diffusion models have been a key enabler, as they excel in image diversity. However, this comes at the cost of slow training and synthesis, which is only partially alleviated by latent diffusion. To this end, flow matching is an appealing approach due to its complementary characteristics of faster training and inference but less diverse synthesis. We demonstrate that introducing flow matching between a frozen diffusion model and a convolutional decoder enables high-resolution image synthesis at reduced computational cost and model size. A small diffusion model can then effectively provide the necessary visual diversity, while flow matching efficiently enhances resolution and detail by mapping the small to a high-dimensional latent space. These latents are then projected to high-resolution images by the subsequent convolutional decoder of the latent diffusion approach. Combining the diversity of diffusion models, the efficiency of flow matching, and the effectiveness of convolutional decoders, state-of-the-art high-resolution image synthesis is achieved at $1024^2$ pixels with minimal computational cost. Further scaling up our method we can reach resolutions up to $2048^2$ pixels. Importantly, our approach is orthogonal to recent approximation and speed-up strategies for the underlying model, making it easily integrable into the various diffusion model frameworks.

Johannes Schusterbauer, Ming Gui, Pingchuan Ma, Nick Stracke, Stefan A. Baumann, Vincent Tao Hu, Björn Ommer
arXiv:2312.07360 · cs.CV · submitted Dec 12, 2023 · updated Dec 4, 2024
abstract · pdf · html · ECCV 2024 (Oral), Project Page: https://compvis.github.io/fm-boosting/

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