Track: long paper (up to 8 pages)
Keywords: Diffusion Model, Inference Enhancement, Reflection Mechanism
TL;DR: We propose a reflection framework for the inference process of diffusion models, leveraging the distribution gap between the exising weak and strong models to enhance a diffusion model into an ideal model, thereby optimizing the sampling trajectory.
Abstract: The goal of diffusion generative models is to align the learned distribution with the real data distribution through gradient score matching. However, inherent limitations in training data quality, modeling strategies, and architectural design lead to inevitable gap between generated outputs and real data. To reduce this gap, we propose Weak-to-Strong Diffusion (**W2SD**), a novel framework that utilizes the estimated difference between existing weak and strong models (i.e., weak-to-strong difference) to bridge the gap between an ideal model and a strong model. By employing a reflective operation that alternates between denoising and inversion with weak-to-strong difference, we theoretically understand that W2SD steers latent variables along sampling trajectories toward regions of the real data distribution. W2SD is highly flexible and broadly applicable, enabling diverse improvements through the strategic selection of weak-to-strong model pairs (e.g., DreamShaper vs. SD1.5, good experts vs. bad experts in MoE). Extensive experiments demonstrate that W2SD significantly improves human preference, aesthetic quality, and prompt adherence, achieving SOTA performance across various modalities (e.g., image, video), architectures (e.g., UNet-based, DiT-based, MoE), and benchmarks. For example, Juggernaut-XL with W2SD can improve with the HPSv2 winning rate up to **90**% over the original results. Moreover, the performance gains achieved by W2SD markedly outweigh its additional computational overhead, while the cumulative improvements from different weak-to-strong difference further solidify its practical utility and deployability. The
code is publicly available at [github.com/xie-lab-ml/Weak-to-Strong-Diffusion-with-Reflection](https://github.com/xie-lab-ml/Weak-to-Strong-Diffusion-with-Reflection).
Submission Number: 53
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