arXiv Machine Learning By Frantzeska Lavda, Maciej Falkiewicz, Van Khoa Nguyen, Alexandros Kalousis

Spatially Adaptive Noise Injection

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Spatially Adaptive Noise Injection (SANI) is a new diffusion sampling framework that adjusts the amount of noise added at each pixel during reverse diffusion. Unlike traditional samplers that apply a uniform noise variance across the image, SANI uses a probabilistic gating mechanism to inject noise only where the denoiser is uncertain, such as edges and textures, while preserving smooth regions. Experiments show that SANI consistently improves Fréchet Inception Distance over vanilla DDPM and DDIM samplers across various timesteps, and remains competitive with variance‑learning baselines.

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