Kernel Density Steering: Inference-Time Scaling via Mode Seeking for Image Restoration

Fuente: arXiv
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Auteurs principaux: Hu, Yuyang, Mei, Kangfu, Sahraee-Ardakan, Mojtaba, Kamilov, Ulugbek S., Milanfar, Peyman, Delbracio, Mauricio
Format: Preprint
Publié: 2025
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author Hu, Yuyang
Mei, Kangfu
Sahraee-Ardakan, Mojtaba
Kamilov, Ulugbek S.
Milanfar, Peyman
Delbracio, Mauricio
author_facet Hu, Yuyang
Mei, Kangfu
Sahraee-Ardakan, Mojtaba
Kamilov, Ulugbek S.
Milanfar, Peyman
Delbracio, Mauricio
contents Diffusion models show promise for image restoration, but existing methods often struggle with inconsistent fidelity and undesirable artifacts. To address this, we introduce Kernel Density Steering (KDS), a novel inference-time framework promoting robust, high-fidelity outputs through explicit local mode-seeking. KDS employs an $N$-particle ensemble of diffusion samples, computing patch-wise kernel density estimation gradients from their collective outputs. These gradients steer patches in each particle towards shared, higher-density regions identified within the ensemble. This collective local mode-seeking mechanism, acting as "collective wisdom", steers samples away from spurious modes prone to artifacts, arising from independent sampling or model imperfections, and towards more robust, high-fidelity structures. This allows us to obtain better quality samples at the expense of higher compute by simultaneously sampling multiple particles. As a plug-and-play framework, KDS requires no retraining or external verifiers, seamlessly integrating with various diffusion samplers. Extensive numerical validations demonstrate KDS substantially improves both quantitative and qualitative performance on challenging real-world super-resolution and image inpainting tasks.
format Preprint
id arxiv_https___arxiv_org_abs_2507_05604
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Kernel Density Steering: Inference-Time Scaling via Mode Seeking for Image Restoration
Hu, Yuyang
Mei, Kangfu
Sahraee-Ardakan, Mojtaba
Kamilov, Ulugbek S.
Milanfar, Peyman
Delbracio, Mauricio
Computer Vision and Pattern Recognition
Image and Video Processing
Diffusion models show promise for image restoration, but existing methods often struggle with inconsistent fidelity and undesirable artifacts. To address this, we introduce Kernel Density Steering (KDS), a novel inference-time framework promoting robust, high-fidelity outputs through explicit local mode-seeking. KDS employs an $N$-particle ensemble of diffusion samples, computing patch-wise kernel density estimation gradients from their collective outputs. These gradients steer patches in each particle towards shared, higher-density regions identified within the ensemble. This collective local mode-seeking mechanism, acting as "collective wisdom", steers samples away from spurious modes prone to artifacts, arising from independent sampling or model imperfections, and towards more robust, high-fidelity structures. This allows us to obtain better quality samples at the expense of higher compute by simultaneously sampling multiple particles. As a plug-and-play framework, KDS requires no retraining or external verifiers, seamlessly integrating with various diffusion samplers. Extensive numerical validations demonstrate KDS substantially improves both quantitative and qualitative performance on challenging real-world super-resolution and image inpainting tasks.
title Kernel Density Steering: Inference-Time Scaling via Mode Seeking for Image Restoration
topic Computer Vision and Pattern Recognition
Image and Video Processing
url https://arxiv.org/abs/2507.05604