A new method called ReGuidance has been introduced to improve sample quality and rewards in solving hard inverse problems with low signal-to-noise ratios.
Diffusion models are being utilized as data priors in solving inverse problems with pretrained models.
Training-free methods like diffusion posterior sampling (DPS) offer flexible algorithms but struggle on hard inverse problems.
ReGuidance involves inverting a candidate solution using probability flow ODE and initializing DPS with the resulting latent.
The ReGuidance wrapper has been tested on tasks like large box in-painting and super-resolution with positive results.
State-of-the-art baseline methods fail on these tasks while ReGuidance significantly improves sample quality and measurement consistency.
Theory suggests ReGuidance can enhance rewards and bring solutions closer to the data manifold, especially on multimodal data distributions.
ReGuidance is the first method to offer a rigorous algorithmic guarantee for diffusion posterior sampling (DPS).