arXiv Computer Vision

LiDAR Resolution Recovery via Foundation-Model-Guided Diffusion

arXiv Computer Vision
Sep 25

FounRef: Robust, Structure-Preserving, and Fast Metric Refinement of Frozen Monocular Foundation Priors with Sparse Anchors

FounRef is a training‑free method that refines frozen monocular foundation priors into dense metric depth by aligning them with sparse metric anchors. It validates anchors against the prior’s predictions, rejects misaligned ones, and applies a structure‑preserving solver to correct depth globally and locally while preserving fine geometry. The approach works out of the box on unseen cameras and scenes, achieving up to 24% lower depth error, 92% lower surface‑normal noise, and nearly 15× faster inference than a leading depth‑completion network.

By Dan Halperin, Mirko M\"ahlisch
arXiv AI
Sep 7

SimFuse3D: Source-Guided Target Simulation and Confidence-Guided Multi-Stage Localization Reweighting for Cross-Platform 3D Object Detection

SimFuse3D tackles cross‑platform LiDAR unsupervised domain adaptation by addressing box‑point inconsistency through source‑guided target simulation and confidence‑guided multi‑stage localization reweighting. It preserves target placement, repairs pseudo‑objects using labeled source geometry, and reweights predictions based on confidence, all during adaptation without altering the detector architecture. The method outperforms existing adaptation techniques across six cross‑platform transfers and ranks first on nuScenes‑to‑KITTI for both evaluated detectors.

By Yongchun Lin, Xinliang Zhang, Yun Zou, Zhixuan Xiao, Liang Lei, Jianya Guo, Yuqiang Zhai, Xiaofeng Wang, HaiKuo Xu, Haoang Li
arXiv Computer Vision
Oct 5

PatchScene: Patch-based Voxel Diffusion for Large-Scale Scene Completion

PatchScene is a diffusion-based framework that completes large-scale LiDAR scenes using a patch-based voxel diffusion paradigm, generating fine-grained geometry in localized 3D regions. It incorporates a confidence-guided spatio-temporal fusion mechanism to merge overlapping patches and adjacent frames, and introduces an Annular-Flow diffusion strategy that propagates high-fidelity information from near to far ranges. Experiments on SemanticKITTI show state-of-the-art performance, with the model trained on 20 m LiDAR ranges generalizing to 50 m scenes without retraining.

By Qingdong Xu, Jiajun Zhu, Shilin Zhu, Xinjing He, Chao Lu, Huanran Wang, Jiyao Zhang
arXiv AI
Oct 9

CRISP: Fixing Flying Pixels in Latent LiDAR Generation via Diffusion Decoding

The paper introduces CRISP, a pixel‑space diffusion decoder designed to eliminate flying pixels in latent LiDAR generation. CRISP replaces existing video‑VAE and LiDAR‑native decoders while keeping the encoder and latent generator unchanged, and it incorporates a backbone‑agnostic latent adapter, a DiT‑based denoiser, and a support mask predictor. Across datasets such as KITTI‑360, SemanticKITTI, and nuScenes, CRISP reduces FSVD/FPVD by an average of 50.5% for frozen backbones and up to 71%/74% for generic video VAEs, achieving significant improvements in depth discontinuity handling and narrowing the sim‑to‑real gap in pretrained LiDM world models.

By Andrea Ceron, Michael Schmidt, Alvaro Marcos-Ramiro, Sebastian Schmidt, Benjamin Busam