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RESEARCH PAPER / 2025-10-06

Differentiable physics for sound field reconstruction

Samuel A. Verburg, Efren Fernandez-Grande, Peter Gerstoft

Technical University of Denmark (DTU) +1 · arXiv

Affiliations: Technical University of Denmark (DTU), Universidad Politécnica de Madrid (UPM)

Abstract

Sound field reconstruction involves estimating sound fields from a limited number of spatially distributed observations. This work introduces a differentiable physics approach for sound field reconstruction, where the initial conditions of the wave equation are approximated with a neural network, and the differential operator is computed with a differentiable numerical solver. The use of a numerical solver enables a stable network training while enforcing the physics as a strong constraint, in contrast to conventional physics-informed neural networks, which include the physics as a constraint in the loss function. We introduce an additional sparsity-promoting constraint to achieve meaningful solutions even under severe undersampling conditions. Experiments demonstrate that the proposed approach can reconstruct sound fields under extreme data scarcity, achieving higher accuracy and better convergence compared to physics-informed neural networks.

The following analysis is generated by AI and may contain errors. It is separate from the authors’ abstract and is not peer review.

Research summary

This work introduces a differentiable physics approach for sound field reconstruction, significantly enhancing accuracy and convergence under data scarcity. The methodology combines neural networks with numerical PDE solvers, showcasing a promising direction for future research in acoustics and machine learning.

Methodology

The paper presents a novel differentiable physics approach that integrates a neural network with a numerical PDE solver for sound field reconstruction. This method improves stability and convergence compared to traditional physics-informed neural networks (PINNs) by directly incorporating physical constraints through the numerical solver rather than as a penalty in the loss function. The introduction of a sparsity-promoting constraint is particularly innovative, allowing the model to perform well under extreme data scarcity. The use of automatic differentiation (AD) to compute gradients through the numerical solver is a significant methodological advancement, streamlining the training process.

Results & evaluation

The experiments conducted are rigorous and demonstrate the effectiveness of the proposed method across various scenarios, including single Gaussian pulses and complex source distributions. The results indicate that the differentiable physics approach significantly outperforms PINNs in terms of accuracy and convergence speed, particularly in highly undersampled conditions. The use of normalized mean squared error (NMSE) as a performance metric is appropriate, and the experiments are well-structured to showcase the strengths of the proposed method.

Reproducibility

The paper provides sufficient detail regarding the implementation, including the architecture of the neural networks, the training process, and the numerical methods used. The availability of the code repository enhances reproducibility, allowing other researchers to replicate the experiments and build upon the work.

Limitations

While the proposed method shows promising results, the paper does not extensively discuss potential limitations, such as the sensitivity of the model to the choice of hyperparameters or the specific numerical methods employed. Additionally, the method may face challenges in more complex acoustic environments that were not tested in the experiments.

Broader impact

The proposed differentiable physics approach has significant implications for sound field reconstruction and could be applied to various fields, including acoustics, audio engineering, and environmental monitoring. The ability to reconstruct sound fields from limited data could enhance applications in virtual reality, architectural acoustics, and audio signal processing. The integration of physics with machine learning also opens avenues for addressing other inverse problems in different domains. This work introduces a differentiable physics approach for sound field reconstruction, significantly enhancing accuracy and convergence under data scarcity. The methodology combines neural networks with numerical PDE solvers, showcasing a promising direction for future research in acoustics and machine learning.

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