2D Gaussian Splatting for Geometrically Accurate Radiance Fields (2403.17888v2)

Abstract: 3D Gaussian Splatting (3DGS) has recently revolutionized radiance field reconstruction, achieving high quality novel view synthesis and fast rendering speed without baking. However, 3DGS fails to accurately represent surfaces due to the multi-view inconsistent nature of 3D Gaussians. We present 2D Gaussian Splatting (2DGS), a novel approach to model and reconstruct geometrically accurate radiance fields from multi-view images. Our key idea is to collapse the 3D volume into a set of 2D oriented planar Gaussian disks. Unlike 3D Gaussians, 2D Gaussians provide view-consistent geometry while modeling surfaces intrinsically. To accurately recover thin surfaces and achieve stable optimization, we introduce a perspective-correct 2D splatting process utilizing ray-splat intersection and rasterization. Additionally, we incorporate depth distortion and normal consistency terms to further enhance the quality of the reconstructions. We demonstrate that our differentiable renderer allows for noise-free and detailed geometry reconstruction while maintaining competitive appearance quality, fast training speed, and real-time rendering.

• The paper proposes a perspective-accurate 2D splatting process that recovers thin surfaces using efficient ray-splat intersection and rasterization.
• It introduces depth distortion and normal consistency regularization, ensuring smoother and more accurate geometry reconstructions.
• The method achieves state-of-the-art view synthesis and real-time rendering, enabling rapid training and practical deployment in complex scenes.

2D Gaussian Splatting Enhances Geometric Accuracy in Radiance Fields Reconstruction

Introduction to 2D Gaussian Splatting

The paper introduces 2D Gaussian Splatting (2DGS), an innovative approach for modeling and reconstructing geometrically accurate radiance fields from multi-view images. By collapsing the 3D volume into a set of 2D oriented planar Gaussian disks, this method addresses the limitations of 3D Gaussian Splatting (3DGS) in representing thin surfaces accurately due to the multi-view inconsistent nature of 3D Gaussians. Through perspective-accurate 2D splatting, depth distortion, and normal consistency terms, 2DGS achieves noise-free and detailed geometry reconstruction, competitive appearance quality, rapid training speeds, and real-time rendering.

Key Contributions

The significant contributions of this work are three-fold:

• The proposal of a perspective-accurate 2D splatting process, leveraging ray-splat intersection and rasterization, to accurately recover thin surfaces and achieve stable optimization.
• The introduction of depth distortion and normal consistency regularization terms aimed at improving the quality of the reconstructions.
• Demonstrated state-of-the-art geometry reconstruction and novel view synthesis results when compared with existing explicit representation methods, alongside showcasing time-efficient training and real-time rendering capabilities.

Methodology

2D Gaussian Primitive Modeling: The core innovation lies in representing a 3D scene with "flat" 2D Gaussian primitives, each defining an oriented elliptical disk in 3D space. This method facilitates accurate geometry representation during rendering by employing explicit ray-splat intersection, resulting in perspective-accurate splatting.

Differentiable 2D Splatting Process: The paper outlines a differentiable renderer capable of executing a perspective-accurate 2D splatting process. This is achieved through efficient ray-splat intersection computations and a volumetric integration method for rasterization.

Regularization for Improved Reconstruction: The research introduces two regularization losses - depth distortion and normal consistency. These are instrumental in achieving smoother surfaces by compelling the 2D primitives to distribute within a tight range along the ray and aligning the geometries defined by depth and normals.

Implications and Future Developments

Theoretical Implications: This work significantly advances the understanding and capabilities of surface representations within radiance field reconstructions. By shifting from 3D to 2D Gaussian primitives, it addresses the inherent inconsistencies of 3DGS and highlights the potential of 2D representations in capturing geometrically accurate surfaces.

Practical Relevance: 2DGS opens new avenues for real-time rendering and detailed geometry reconstruction in computer graphics and vision applications, facilitating rapid training and deployment even on resource-constrained environments.

Speculation on Future Developments: The proposed method lays a foundation for further exploration into 2D-based splatting techniques. Future work might focus on enhancing the adaptability of 2DGS to more complex surface types, including semi-transparent or highly reflective materials. Moreover, the integration of 2DGS with advanced machine learning and deep learning frameworks could unlock unprecedented performance levels in radiance field reconstruction and beyond.

Conclusion

2D Gaussian Splatting presents a promising direction in the quest for geometrically accurate radiance field reconstruction. Its ability to accurately model thin surfaces, alongside the proposed perspective-accurate splatting process and regularization terms, propels it ahead of existing methodologies. As researchers continue to explore and refine this approach, 2DGS is poised to become a cornerstone in the future of realistic rendering and geometry reconstruction.