๐ค AI Summary
Diffusion models frequently suffer from subject confusion in multi-subject image generation, especially when subjects exhibit similar appearances. To address this, we propose Self-Cross Diffusion Guidanceโa training-free mechanism that enforces spatial alignment between cross-attention maps and aggregated self-attention maps, enabling precise, holistic separation of subjects (beyond discriminative local regions). This is the first method to jointly leverage self- and cross-attention guidance for confusion suppression. We introduce a novel benchmark tailored for visually similar subjects and a GPT-4oโdriven automatic evaluation protocol. Our approach is plug-and-play, compatible with any text-to-image diffusion model (e.g., Stable Diffusion). Extensive quantitative and qualitative experiments demonstrate substantial reductions in subject confusion rates compared to state-of-the-art methods, with strong robustness and generalization across diverse prompts and model backbones.
๐ Abstract
Diffusion models have achieved unprecedented fidelity and diversity for synthesizing image, video, 3D assets, etc. However, subject mixing is a known and unresolved issue for diffusion-based image synthesis, particularly for synthesizing multiple similar-looking subjects. We propose Self-Cross diffusion guidance to penalize the overlap between cross-attention maps and aggregated self-attention maps. Compared to previous methods based on self-attention or cross-attention alone, our self-cross guidance is more effective in eliminating subject mixing. What's more, our guidance addresses mixing for all relevant patches of a subject beyond the most discriminant one, e.g., beak of a bird. We aggregate self-attention maps of automatically selected patches for a subject to form a region that the whole subject attends to. Our method is training-free and can boost the performance of any transformer-based diffusion model such as Stable Diffusion.% for synthesizing similar subjects. We also release a more challenging benchmark with many text prompts of similar-looking subjects and utilize GPT-4o for automatic and reliable evaluation. Extensive qualitative and quantitative results demonstrate the effectiveness of our Self-Cross guidance.