AION
Research paperImage, Video & 3D Generation1 source · Oct 6, 2026

Two Halves are More than One: Phase-wise Velocity Distillation for Fast and High-Quality Image Generation

Recent diffusion-based image generation backbones have grown substantially in scale, making the network inference cost increase rapidly.

Key points

  • While diffusion distillation techniques can reduce the number of inference steps, high-quality image generation within a single full-backbone-forward compute budget remains challenging.
  • To address this issue, we propose Phase-wise Velocity Distillation (PVD), which partitions the generation timeline into a coarse and a fine phase, and models the transition within each phase via the average velocity.
  • We show that the use of two half-sized phase-specific experts outperforms a single full-size monolithic student.
  • On more complex text-to-image (T2I) tasks, PVD-distilled models (Stable Diffusion 3.5-Medium, FLUX.1-dev, Qwen-Image) produce results competitive with their multi-step teachers, significantly outperforming prior distillation methods.

Sources (1)

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