Splat Regression Models

ICLR 2026 Conference SubmissionAnonymous Authors
WassersteinFisher-Raogradient flowgaussian splattingscientific machine learning
Abstract:

We introduce a highly expressive class of function approximators called Splat Regression Models. Model outputs are mixtures of heterogeneous and anisotropic bump functions, termed splats, each weighted by an output vector. The power of splat modeling lies in its ability to locally adjust the scale and direction of each splat, achieving both high interpretability and accuracy. Fitting splat models reduces to optimization over the space of mixing measures, which can be implemented using Wasserstein-Fisher-Rao gradient flows. As a byproduct, we recover the popular Gaussian Splatting methodology as a special case, providing a unified theoretical framework for this state-of-the-art technique that clearly disambiguates the inverse problem, the model, and the optimization algorithm. Through numerical experiments, we demonstrate that the resulting models and algorithms constitute a flexible and promising approach for solving diverse approximation, estimation, and inverse problems involving low-dimensional data.

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Overview

Overall Novelty Assessment

The paper introduces Splat Regression Models, a class of function approximators using heterogeneous and anisotropic bump functions (splats) weighted by output vectors. It resides in the Computer Vision and Image Processing leaf, which contains only three papers total. This leaf sits within Domain-Specific Applications and Methodologies, one of four major branches in a 50-paper taxonomy. The sparse population of this leaf suggests that mixture-based regression methods tailored specifically to vision tasks remain relatively underexplored compared to broader algorithmic or theoretical directions.

The taxonomy reveals that neighboring leaves address distinct application domains—Causal Inference, Survival Analysis, Time Series, Reinforcement Learning, and others—each with one to three papers. Within the same branch, the paper's sibling works (Multivariate Mixture Registration and Semantic Gaussian Bundle) focus on image registration and semantic 3D reconstruction, respectively. The broader Algorithmic Methods branch contains denser clusters (Bayesian Inference, Frequentist Estimation, Neural Network Integration), while Model Specification explores robustness and spatial extensions. Splat Regression bridges vision-specific needs with general mixture approximation theory, diverging from purely statistical or neural approaches.

Among 30 candidates examined, none clearly refuted any of the three contributions. Contribution A (Splat Regression Models) examined 10 candidates with zero refutable overlaps; Contribution B (Wasserstein-Fisher-Rao gradient flows) and Contribution C (unified Gaussian Splatting framework) each examined 10 candidates, also with zero refutations. This limited search scope—top-K semantic matches plus citation expansion—suggests that within the examined literature, the specific combination of splat-based approximation, WFR optimization, and theoretical unification of Gaussian Splatting appears novel, though exhaustive coverage of the broader vision and optimization literature was not performed.

Based on the limited search, the work appears to occupy a relatively sparse niche at the intersection of mixture regression theory and computer vision. The taxonomy structure indicates that while mixture models are well-studied in statistical and algorithmic contexts, their application to vision-specific approximation problems remains less crowded. However, the analysis covers only 30 candidates from semantic search, leaving open the possibility of relevant prior work in adjacent optimization or graphics communities not captured by this scope.

Taxonomy

Core-task Taxonomy Papers
50
3
Claimed Contributions
30
Contribution Candidate Papers Compared
0
Refutable Paper

Research Landscape Overview

Core task: Regression and approximation using heterogeneous mixture models. The field encompasses a broad spectrum of methodological and applied research organized into four main branches. Theoretical Foundations and Approximation Guarantees establish the mathematical underpinnings, examining convergence properties and error bounds for mixture-based estimators. Algorithmic Methods and Computational Techniques focus on efficient inference procedures, including EM variants, variational approaches such as MAP Variational Bayes[15], and spectral methods like Spectral Experts[35]. Model Specification and Structural Extensions explore diverse architectural choices—ranging from location-scale formulations (Location Scale Mixtures[10]) to functional and hierarchical designs (Functional Mixture Experts[9], Hierarchical Priors Mixtures[7])—that allow mixtures to capture complex heterogeneity. Domain-Specific Applications and Methodologies translate these tools into practical settings, addressing challenges in computer vision, econometrics (Demand Heterogeneity[39]), survival analysis (Deep Cox Mixtures[24]), and traffic modeling (Five Experts Traffic[6]). Recent work highlights several active themes and trade-offs. One line emphasizes robustness and heavy-tailed component distributions, as seen in Robust Mixture Regression[17] and Gaussian Cauchy Kalman[20], which handle outliers more gracefully than standard Gaussian mixtures. Another explores semiparametric and nonparametric extensions (Semiparametric Mixture Regressions[16]) that relax parametric assumptions while maintaining tractability. Within the computer vision branch, Splat Regression[0] sits alongside methods like Multivariate Mixture Registration[38] and Semantic Gaussian Bundle[43], all leveraging mixture representations for image-level tasks. Splat Regression[0] emphasizes spatial approximation via Gaussian splatting primitives, contrasting with Semantic Gaussian Bundle[43], which integrates semantic information into bundle-adjusted reconstructions, and Multivariate Mixture Registration[38], which focuses on aligning multivariate functional data. These neighboring works illustrate how mixture models adapt to vision-specific requirements—balancing expressiveness, computational efficiency, and interpretability in high-dimensional visual domains.

Claimed Contributions

Splat Regression Models

The authors propose a new function approximation architecture where model outputs are mixtures of heterogeneous and anisotropic bump functions (splats), each weighted by an output vector. The model achieves high interpretability and accuracy by locally adjusting the scale and direction of each splat.

10 retrieved papers
Wasserstein-Fisher-Rao gradient flow optimization framework

The authors develop a principled optimization method for training splat models by interpreting model parameters as hierarchical distributions and applying Wasserstein-Fisher-Rao gradient flow theory to compute gradient updates in parameter space.

10 retrieved papers
Unified theoretical framework for Gaussian Splatting

The authors show that 3D Gaussian Splatting is a special instance of splat regression modeling, offering a clean formulation that separates the inverse problem, model architecture, and optimization algorithm into modular components.

10 retrieved papers

Core Task Comparisons

Comparisons with papers in the same taxonomy category

Contribution Analysis

Detailed comparisons for each claimed contribution

Contribution

Splat Regression Models

The authors propose a new function approximation architecture where model outputs are mixtures of heterogeneous and anisotropic bump functions (splats), each weighted by an output vector. The model achieves high interpretability and accuracy by locally adjusting the scale and direction of each splat.

Contribution

Wasserstein-Fisher-Rao gradient flow optimization framework

The authors develop a principled optimization method for training splat models by interpreting model parameters as hierarchical distributions and applying Wasserstein-Fisher-Rao gradient flow theory to compute gradient updates in parameter space.

Contribution

Unified theoretical framework for Gaussian Splatting

The authors show that 3D Gaussian Splatting is a special instance of splat regression modeling, offering a clean formulation that separates the inverse problem, model architecture, and optimization algorithm into modular components.

Splat Regression Models | Novelty Validation