Hawk: Leveraging Spatial Context for Faster Autoregressive Text-to-Image Generation

Han-Jia Ye (Nanjing University) · Zhi-Kai Chen (Nanjing University) · Jun-Peng Jiang (NanJing University) · De-Chuan Zhan (Nanjing University)
alignmentautoregressive modelscomputational speedupdraft modelimage diversityimage fidelityimage generationlocal dependenciesprediction accuracysampling spacespatial structurespeculative decodingtext-to-image benchmarkstoken-by-token decoding

Autoregressive (AR) image generation models are capable of producing high-fidelity images but often suffer from slow inference due to their inherently sequential, token-by-token decoding process. Speculative decoding, which employs a lightweight draft model to approximate the output of a larger AR model, has shown promise in accelerating text generation without compromising quality. However, its application to image generation remains largely underexplored. The challenges stem from a significantly larger sampling space, which complicates the alignment between the draft and target model outputs, coupled with the inadequate use of the two-dimensional spatial structure inherent in images, thereby limiting the modeling of local dependencies. To overcome these challenges, we introduce Hawk, a new approach that harnesses the spatial structure of images to guide the speculative model toward more accurate and efficient predictions. Experimental results on multiple text-to-image benchmarks demonstrate a 1.71× speedup over standard AR models, while preserving both image fidelity and diversity.