TAG: Tangential Amplifying Guidance for Hallucination-Resistant Sampling

Abstract

Recent diffusion models achieve the state-of-the-art performance in image generation, but often suffer from semantic inconsistencies or *hallucinations*. While various inference-time guidance methods can enhance generation, they often operate *indirectly* by relying on external signals or architectural modifications, which introduces additional computational overhead. In this paper, we propose **T**angential **A**mplifying **G**uidance **(TAG)**, a theoretically grounded, training-free, computationally lightweight, and architecture-agnostic guidance method that operates solely on trajectory signals without modifying the underlying diffusion model. TAG leverages an intermediate sample as a projection basis and amplifies the tangential components of the estimated scores with respect to this basis to correct the sampling trajectory. We formalize this guidance process via a first-order Taylor analysis, showing that tangential amplification steers the state toward higher-probability regions of the data manifold, thereby reducing inconsistencies and improving sample fidelity. TAG is a plug-and-play module that integrates into existing diffusion samplers with minimal additional computation, offering a new perspective on diffusion guidance.