基于物理信息神经场的动态黑洞发射断层成像
Dynamic Black-hole Emission Tomography with Physics-informed Neural Fields
将可微分神经渲染与物理约束（速度场作为发射率动力学的软约束）结合，用于从稀疏单视角测量中重建动态 3D 场，这种联合优化 4D 发射率与 3D 速度场的思路可迁移到其他病态动态重建问题（如流体、动态 NeRF）。
原文依据 we propose PI-DEF, a physics-informed approach that uses differentiable neural rendering to fit a 4D (time + 3D) emissivity field given EHT measurements
摘要译文
由模型翻译 · 术语统一 · 请对照原文核对关键结论随着静态黑洞成像的成功，下一个前沿是黑洞的动态与三维成像。恢复黑洞附近的动态三维气体将揭示宇宙中此前未见的部分，并为新物理模型提供信息。然而，仅能获得来自单一视角的稀疏射电测量，这使得动态三维重建问题严重病态。此前，BH-NeRF 通过假设气体的开普勒动力学来处理这一病态问题，但该假设在黑洞附近失效，因为黑洞的强引力与增强的电磁活动使流体动力学复杂化。为克服 BH-NeRF 的限制性假设，我们提出 PI-DEF，一种物理信息方法，利用可微分神经渲染，根据 EHT 测量拟合 4D（时间 + 三维）发射率场。我们的方法联合重建三维速度场与 4D 发射率场，并将速度作为发射率动力学的软约束。在模拟数据上的实验中，我们发现重建精度显著优于 BH-NeRF 和一种物理不可知方法。我们展示了如何利用我们的方法估计黑洞的其他物理参数，例如其自旋。
英文原文摘要 1287 字符
With the success of static black-hole imaging, the next frontier is the dynamic and 3D imaging of black holes. Recovering the dynamic 3D gas near a black hole would reveal previously-unseen parts of the universe and inform new physics models. However, only sparse radio measurements from a single viewpoint are possible, making the dynamic 3D reconstruction problem significantly ill-posed. Previously, BH-NeRF addressed the ill-posed problem by assuming Keplerian dynamics of the gas, but this assumption breaks down near the black hole, where the strong gravitational pull of the black hole and increased electromagnetic activity complicate fluid dynamics. To overcome the restrictive assumptions of BH-NeRF, we propose PI-DEF, a physics-informed approach that uses differentiable neural rendering to fit a 4D (time + 3D) emissivity field given EHT measurements. Our approach jointly reconstructs the 3D velocity field with the 4D emissivity field and enforces the velocity as a soft constraint on the dynamics of the emissivity. In experiments on simulated data, we find significantly improved reconstruction accuracy over both BH-NeRF and a physics-agnostic approach. We demonstrate how our method may be used to estimate other physics parameters of the black hole, such as its spin.