Pyramidal Patchification Flow for Visual Generation

Fuente: arXiv
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Autores principales: Li, Hui, Chen, Baoyou, Zhang, Liwei, Li, Jiaye, Wang, Jingdong, Zhu, Siyu
Formato: Preprint
Publicado: 2025
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author Li, Hui
Chen, Baoyou
Zhang, Liwei
Li, Jiaye
Wang, Jingdong
Zhu, Siyu
author_facet Li, Hui
Chen, Baoyou
Zhang, Liwei
Li, Jiaye
Wang, Jingdong
Zhu, Siyu
contents Diffusion transformers (DiTs) adopt Patchify, mapping patch representations to token representations through linear projections, to adjust the number of tokens input to DiT blocks and thus the computation cost. Instead of a single patch size for all the timesteps, we introduce a Pyramidal Patchification Flow (PPFlow) approach: Large patch sizes are used for high noise timesteps and small patch sizes for low noise timesteps; Linear projections are learned for each patch size; and Unpatchify is accordingly modified. Unlike Pyramidal Flow, our approach operates over full latent representations other than pyramid representations, and adopts the normal denoising process without requiring the renoising trick. We demonstrate the effectiveness of our approach through two training manners. Training from scratch achieves a $1.6\times$ ($2.0\times$) inference speed over SiT-B/2 for 2-level (3-level) pyramid patchification with slightly lower training FLOPs and similar image generation performance. Training from pretrained normal DiTs achieves even better performance with small training time. The code and checkpoint are at https://github.com/fudan-generative-vision/PPFlow.
format Preprint
id arxiv_https___arxiv_org_abs_2506_23543
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Pyramidal Patchification Flow for Visual Generation
Li, Hui
Chen, Baoyou
Zhang, Liwei
Li, Jiaye
Wang, Jingdong
Zhu, Siyu
Computer Vision and Pattern Recognition
Diffusion transformers (DiTs) adopt Patchify, mapping patch representations to token representations through linear projections, to adjust the number of tokens input to DiT blocks and thus the computation cost. Instead of a single patch size for all the timesteps, we introduce a Pyramidal Patchification Flow (PPFlow) approach: Large patch sizes are used for high noise timesteps and small patch sizes for low noise timesteps; Linear projections are learned for each patch size; and Unpatchify is accordingly modified. Unlike Pyramidal Flow, our approach operates over full latent representations other than pyramid representations, and adopts the normal denoising process without requiring the renoising trick. We demonstrate the effectiveness of our approach through two training manners. Training from scratch achieves a $1.6\times$ ($2.0\times$) inference speed over SiT-B/2 for 2-level (3-level) pyramid patchification with slightly lower training FLOPs and similar image generation performance. Training from pretrained normal DiTs achieves even better performance with small training time. The code and checkpoint are at https://github.com/fudan-generative-vision/PPFlow.
title Pyramidal Patchification Flow for Visual Generation
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2506.23543