DeCorStory: Gram-Schmidt Prompt Embedding Decorrelation for Consistent Storytelling
Ayushman Sarkar, Zhenyu Yu, Mohd Yamani Idna Idris
TL;DR
DeCorStory addresses inter-frame semantic interference in training-free multi-frame text-to-image storytelling by explicitly decorrelating frame-level prompt embeddings with Gram-Schmidt, while amplifying frame-specific semantics via Singular-Value Reweighting and stabilizing identity through Identity-Preserving Cross-Attention. The framework operates entirely at inference time, requiring no model fine-tuning and integrating into standard diffusion pipelines. On ConsiStory+ data, it achieves state-of-the-art performance among training-free baselines in prompt alignment and identity consistency, supported by a human user study. Overall, the approach demonstrates that embedding decorrelation coupled with targeted conditioning significantly improves narrative coherence and subject fidelity in diffusion-based storytelling.
Abstract
Maintaining visual and semantic consistency across frames is a key challenge in text-to-image storytelling. Existing training-free methods, such as One-Prompt-One-Story, concatenate all prompts into a single sequence, which often induces strong embedding correlation and leads to color leakage, background blending, and identity drift. We propose DeCorStory, a training-free inference-time framework that explicitly reduces inter-frame semantic interference. DeCorStory applies Gram-Schmidt prompt embedding decorrelation to orthogonalize frame-level semantics, followed by singular value reweighting to strengthen prompt-specific information and identity-preserving cross-attention to stabilize character identity during diffusion. The method requires no model modification or fine-tuning and can be seamlessly integrated into existing diffusion pipelines. Experiments demonstrate consistent improvements in prompt-image alignment, identity consistency, and visual diversity, achieving state-of-the-art performance among training-free baselines. Code is available at: https://github.com/YuZhenyuLindy/DeCorStory
