🤖 AI Summary
This work addresses the limitations of diffusion models in computational efficiency and the constrained generation quality of autoregressive models caused by discretization and error accumulation. To overcome these challenges, the authors propose the Generative Refinement Network (GRN), which constructs a near-lossless latent space through hierarchical binary quantization, incorporates a human-like global refinement mechanism inspired by artistic painting practices, and introduces an entropy-guided sampling strategy enabling adaptive-step generation. GRN achieves state-of-the-art results on ImageNet with a reconstruction rFID of 0.56 and a class-conditional gFID of 1.81. Furthermore, it demonstrates exceptional performance in text-to-image and text-to-video generation tasks, significantly advancing both generation quality and efficiency.
📝 Abstract
While diffusion models dominate the field of visual generation, they are computationally inefficient, applying a uniform computational effort regardless of different complexity. In contrast, autoregressive (AR) models are inherently complexity-aware, as evidenced by their variable likelihoods, but are often hindered by lossy discrete tokenization and error accumulation. In this work, we introduce Generative Refinement Networks (GRN), a next-generation visual synthesis paradigm to address these issues. At its core, GRN addresses the discrete tokenization bottleneck through a theoretically near-lossless Hierarchical Binary Quantization (HBQ), achieving a reconstruction quality comparable to continuous counterparts. Built upon HBQ's latent space, GRN fundamentally upgrades AR generation with a global refinement mechanism that progressively perfects and corrects artworks -- like a human artist painting. Besides, GRN integrates an entropy-guided sampling strategy, enabling complexity-aware, adaptive-step generation without compromising visual quality. On the ImageNet benchmark, GRN establishes new records in image reconstruction (0.56 rFID) and class-conditional image generation (1.81 gFID). We also scale GRN to more challenging text-to-image and text-to-video generation, delivering superior performance on an equivalent scale. We release all models and code to foster further research on GRN.