Rethinking Cross-Modal Interaction in Multimodal Diffusion Transformers
Authors: name: Zhengyao Lv, name: Tianlin Pan, name: Chenyang Si, name: Zhaoxi Chen, name: Wangmeng Zuo, name: Ziwei Liu, name: Kwan-Yee K. Wong

Multimodal Diffusion Transformers (MM-DiTs) have achieved remarkable progress
in text-driven visual generation. However, even state-of-the-art MM-DiT models
like FLUX struggle with achieving precise alignment between text prompts and
generated content. We identify two key issues in the attention mechanism of
MM-DiT, namely 1) the suppression of cross-modal attention due to token
imbalance between visual and textual modalities and 2) the lack of
timestep-aware attention weighting, which hinder the alignment. To address
these issues, we propose Temperature-Adjusted Cross-modal Attention
(TACA), a parameter-efficient method that dynamically rebalances multimodal
interactions through temperature scaling and timestep-dependent adjustment.
When combined with LoRA fine-tuning, TACA significantly enhances text-image
alignment on the T2I-CompBench benchmark with minimal computational overhead.
We tested TACA on state-of-the-art models like FLUX and SD3.5, demonstrating
its ability to improve image-text alignment in terms of object appearance,
attribute binding, and spatial relationships. Our findings highlight the
importance of balancing cross-modal attention in improving semantic fidelity in
text-to-image diffusion models. Our codes are publicly available at
https://github.com/Vchitect/TACA