Research
New Training Method Improves Knowledge Distillation for Compact Generative AI
Abstract We demonstrate that in knowledge distillation for diffusion models, the teacher network's highly complex denoising process—stemming from its substantially larger capacity—poses a significant challenge for the student model to faithfully mimic. To address this problem, we propose a coarse-to-fine distillation framework with LInear Fitting-based distillation (LIFT) and Piecewise Local Adaptive Coefficient Estimation (PLACE). First, LIFT decomposes the objective into a coarse'' alignment and afine'' refinement. The student is then trained on coarse alignment before proceeding to hard refinement. Second, LInear Fitting-based distillation extends LIFT to address spatially non-uniform errors by partitioning outputs into error-based groups, providing locally adaptive guidance. Our comprehensive experimental results demonstrate that ours, \core~with \pick, outperforms previous knowledge distillation on diffusion models based on both U-Net and DiT architectures. Furthermore, as compression rates become exceedingly high, conventional knowledge distillation fails to provide sufficient guidance, thereby preventing lightweight diffusion models from achieving stable training. In contrast, our method demonstrates stable convergence even under such extreme compression ratios. Compact generative AI models promise to bring image generation to personal devices, but reducing model size often comes at the expense of image quality and training stability. Researchers at UNIST have developed a new knowledge distillation framework that enables lightweight diffusion models to learn more effectively from much larger models without increasing inference costs. Led by Professor Jaejun Yoo of the Graduate School of Artificial Intelligence, the study addresses a key challenge in knowledge distillation—the process of transferring the capabilities of a large AI model to a smaller one. The researchers found that as teacher models become increasingly capable, the complexity of their denoising process makes it progressively more difficult for compact student models to reproduce faithfully. Rather than asking the student model to reproduce every detail from the outset, the framework restructures learning into successive stages, allowing it to first capture an image's overall structure before progressively refining finer details. The approach further improves learning by providing additional guidance where prediction errors are greatest while adapting supervision throughout training. This strategy is implemented through two complementary techniques, LIFT (LInear Fitting-based Distillation) and PLACE (Piecewise Local Adaptive Coefficient Estimation). The approach changes only the training strategy, requiring neither additional model parameters nor extra computation during image generation. Across multiple image-generation benchmarks, the proposed framework consistently outperformed existing knowledge distillation methods. It proved effective for text-to-image synthesis, class-conditional generation, and unconditional image generation, while remaining compatible with multiple diffusion architectures, including U-Net, DiT, and MMDiT, the architecture used in Stable Diffusion 3. The advantages became particularly evident under extreme model compression, where the widening gap between teacher and student models often leaves conventional knowledge distillation unable to provide sufficient guidance for stable learning. When compressing a teacher model containing 78.7 million parameters into a student model with just 1.3 million parameters, the proposed method maintained stable convergence and generated substantially higher-quality images. “Rather than modifying model architectures, our approach improves how compact models learn from larger ones,” said Professor Yoo. “Because it introduces no additional model parameters or inference-time computation, it can be readily applied across a wide range of generative AI models, making compact generative AI practical across a wide range of computing environments.” Hyunsoo Han and Sangyeob Yeo of the Graduate School of Artificial Intelligence at UNIST contributed to the study. The findings have been accepted for presentation at the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR) 2026. Journal Reference Hyunsoo Han, Sangyeop Yeo, and Jaejun Yoo, "LIFT and PLACE: A Simple, Stable, and Effective Knowledge Distillation Framework for Lightweight Diffusion Models," CVPR'26