Uncertainty-Aware 3D Reconstruction for Dynamic Underwater Scenes

ICLR 2026 Conference SubmissionAnonymous Authors
Underwater ReconstructionDynamic Reconstruction
Abstract:

Underwater 3D reconstruction remains challenging due to the intricate interplay between light scattering and environment dynamics. While existing methods yield plausible reconstruction with rigid scene assumptions, they struggle to capture temporal dynamics and remain sensitive to observation noise. In this work, we propose an Uncertainty-aware Dynamic Field (UDF) that jointly represents underwater structure and view-dependent medium over time. A canonical underwater representation is initialized using a set of 3D Gaussians embedded in a volumetric medium field. Then we map this representation into a 4D neural voxel space and encode spatial-temporal features by querying the voxels. Based on these features, a deformation network and a medium offset network are proposed to model transformations of Gaussians and time-conditioned updates to medium properties, respectively. To address input-dependent noise, we model per-pixel uncertainty guided by surface-view radiance ambiguity and inter-frame scene flow inconsistency. This uncertainty is incorporated into the rendering loss to suppress the noise from low-confidence observations during training. Experiments on both controlled and in-the-wild underwater datasets demonstrate our method achieves both high-quality reconstruction and novel view synthesis. Our code will be released.

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Overview

Overall Novelty Assessment

The paper proposes an Uncertainty-aware Dynamic Field (UDF) that jointly models underwater structure, view-dependent medium properties, and temporal dynamics using 3D Gaussians embedded in a volumetric medium field. It resides in the 'Neural Radiance Field Extensions' leaf of the taxonomy, which contains four papers total—including the original work and three siblings. This represents a relatively sparse research direction within the broader neural scene representation branch, suggesting the combination of uncertainty quantification, dynamic modeling, and medium-aware rendering for underwater scenes remains an emerging area rather than a crowded subfield.

The taxonomy tree reveals that the paper's immediate neighbors focus on probabilistic extensions of neural radiance fields for underwater reconstruction, while a sibling category ('Gaussian Splatting for Underwater Scenes') explores explicit representations with physics-aware models. Adjacent branches address uncertainty-aware mapping and localization through SLAM frameworks, classical reconstruction with quality assessment, and specialized estimation tasks like seafloor topography. The paper bridges neural representation methods with uncertainty quantification, connecting to both the neural rendering community and the broader robotic perception literature that emphasizes confidence estimation under challenging visibility conditions.

Among the 23 candidates examined through top-K semantic search and citation expansion, none were found to clearly refute any of the three core contributions. The first contribution (UDF framework) was assessed against 10 candidates with no refutable overlap; the second (motion-aware medium dynamics) similarly examined 10 candidates without finding prior work that anticipates the specific combination of deformation networks and time-conditioned medium offsets; the third (heteroscedastic uncertainty modeling) reviewed 3 candidates, again without identifying clear precedent. This suggests that within the limited search scope, the integration of dynamic scene modeling, medium-aware rendering, and input-dependent uncertainty appears relatively novel.

The analysis is constrained by the scale of the literature search—23 candidates from semantic retrieval rather than an exhaustive survey. While no refutable prior work emerged in this sample, the sparse population of the taxonomy leaf and the absence of overlapping contributions among examined papers indicate the work occupies a distinct position. However, the limited scope means potentially relevant work outside the top-K matches or in adjacent communities may not have been captured, and a broader search could reveal closer antecedents or parallel efforts.

Taxonomy

Core-task Taxonomy Papers
29
3
Claimed Contributions
23
Contribution Candidate Papers Compared
0
Refutable Paper

Research Landscape Overview

Core task: uncertainty-aware 3D reconstruction for dynamic underwater scenes. The field spans a diverse set of approaches organized into several major branches. Neural Scene Representation Methods leverage modern differentiable rendering techniques—such as neural radiance fields and Gaussian splatting—to capture complex underwater appearance and geometry, often incorporating medium-specific effects like scattering and attenuation. Uncertainty-Aware Mapping and Localization focuses on probabilistic frameworks for SLAM and sensor fusion, quantifying confidence in pose estimates and map features under challenging visibility and acoustic conditions. Classical and Hybrid Reconstruction Methods combine traditional photogrammetry or structure-from-motion pipelines with learning-based components, balancing interpretability and robustness. Path Planning and Inspection, Tracking and Prediction Systems, and Specialized Estimation and Reconstruction Tasks address downstream robotic applications—view planning, target tracking, and task-specific inference—while Probabilistic and Stochastic Modeling Foundations provide the mathematical underpinnings for reasoning about noise and variability across sensors and environments. Within the neural representation branch, a small cluster of works has emerged that explicitly models uncertainty in learned scene models. Uncertainty Aware Underwater Reconstruction[0] sits squarely in this line, extending neural radiance field methods to quantify reconstruction confidence in dynamic underwater settings. It shares close ties with Uncertainty Neural Reflectance Underwater[1] and Bayesian Underwater Neural Radiance[15], both of which also embed probabilistic reasoning into differentiable rendering pipelines, though each emphasizes different aspects of the forward model or inference strategy. Nearby efforts like Underwater vSLAM Neural Radiance[24] integrate these representations with simultaneous localization, illustrating how neural methods increasingly bridge classical mapping concerns with modern volumetric scene encoding. The main open questions revolve around scaling these probabilistic neural approaches to larger scenes, handling real-time dynamics, and fusing heterogeneous sensor modalities while maintaining tractable uncertainty estimates.

Claimed Contributions

Uncertainty-aware Dynamic Field (UDF) for underwater reconstruction

The authors introduce a unified framework that simultaneously models time-varying 3D geometry using Gaussian primitives and dynamic participating medium properties. This representation captures both structural evolution and motion-aware medium changes in underwater environments.

10 retrieved papers
Motion-aware medium dynamics modeling

The method employs two specialized networks: a deformation network that predicts geometric transformations of 3D Gaussians over time, and a medium offset network that updates volumetric medium attributes conditioned on scene motion. This enables consistent representation of dynamic geometry and motion-aware medium effects.

10 retrieved papers
Heteroscedastic uncertainty modeling for underwater observations

The authors formulate input-dependent uncertainty by combining two physically grounded cues: surface-view radiance ambiguity (when ray direction aligns with surface normal) and inter-frame flow inconsistency (temporal instability from motion). This per-pixel variance is integrated into a probabilistic rendering loss to adaptively down-weight unreliable observations during training.

3 retrieved papers

Core Task Comparisons

Comparisons with papers in the same taxonomy category

Contribution Analysis

Detailed comparisons for each claimed contribution

Contribution

Uncertainty-aware Dynamic Field (UDF) for underwater reconstruction

The authors introduce a unified framework that simultaneously models time-varying 3D geometry using Gaussian primitives and dynamic participating medium properties. This representation captures both structural evolution and motion-aware medium changes in underwater environments.

Contribution

Motion-aware medium dynamics modeling

The method employs two specialized networks: a deformation network that predicts geometric transformations of 3D Gaussians over time, and a medium offset network that updates volumetric medium attributes conditioned on scene motion. This enables consistent representation of dynamic geometry and motion-aware medium effects.

Contribution

Heteroscedastic uncertainty modeling for underwater observations

The authors formulate input-dependent uncertainty by combining two physically grounded cues: surface-view radiance ambiguity (when ray direction aligns with surface normal) and inter-frame flow inconsistency (temporal instability from motion). This per-pixel variance is integrated into a probabilistic rendering loss to adaptively down-weight unreliable observations during training.