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Main Authors: Zhan, Mingxia, Zhang, Li, Wang, Beibei, Wang, Yingjie, Shi, Zenglin
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2601.01457
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author Zhan, Mingxia
Zhang, Li
Wang, Beibei
Wang, Yingjie
Shi, Zenglin
author_facet Zhan, Mingxia
Zhang, Li
Wang, Beibei
Wang, Yingjie
Shi, Zenglin
contents Relative-depth foundation models transfer well, yet monocular metric depth remains ill-posed due to unidentifiable global scale and heightened domain-shift sensitivity. Under a frozen-backbone calibration setting, we recover metric depth via an image-specific affine transform in inverse depth and train only lightweight calibration heads while keeping the relative-depth backbone and the CLIP text encoder fixed. Since captions provide coarse but noisy scale cues that vary with phrasing and missing objects, we use language to predict an uncertainty-aware envelope that bounds feasible calibration parameters in an unconstrained space, rather than committing to a text-only point estimate. We then use pooled multi-scale frozen visual features to select an image-specific calibration within this envelope. During training, a closed-form least-squares oracle in inverse depth provides per-image supervision for learning the envelope and the selected calibration. Experiments on NYUv2 and KITTI improve in-domain accuracy, while zero-shot transfer to SUN-RGBD and DDAD demonstrates improved robustness over strong language-only baselines.
format Preprint
id arxiv_https___arxiv_org_abs_2601_01457
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Language as Prior, Vision as Calibration: Metric Scale Recovery for Monocular Depth Estimation
Zhan, Mingxia
Zhang, Li
Wang, Beibei
Wang, Yingjie
Shi, Zenglin
Computer Vision and Pattern Recognition
Relative-depth foundation models transfer well, yet monocular metric depth remains ill-posed due to unidentifiable global scale and heightened domain-shift sensitivity. Under a frozen-backbone calibration setting, we recover metric depth via an image-specific affine transform in inverse depth and train only lightweight calibration heads while keeping the relative-depth backbone and the CLIP text encoder fixed. Since captions provide coarse but noisy scale cues that vary with phrasing and missing objects, we use language to predict an uncertainty-aware envelope that bounds feasible calibration parameters in an unconstrained space, rather than committing to a text-only point estimate. We then use pooled multi-scale frozen visual features to select an image-specific calibration within this envelope. During training, a closed-form least-squares oracle in inverse depth provides per-image supervision for learning the envelope and the selected calibration. Experiments on NYUv2 and KITTI improve in-domain accuracy, while zero-shot transfer to SUN-RGBD and DDAD demonstrates improved robustness over strong language-only baselines.
title Language as Prior, Vision as Calibration: Metric Scale Recovery for Monocular Depth Estimation
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2601.01457