Abstract
We present a novel framework for scene representation and rendering that combines 3D Gaussian splatting with dual spherical harmonics decomposition to enable high-quality novel view synthesis under arbitrary lighting conditions. Our key innovation lies in separately modeling diffuse and specular reflection components using distinct directional parameterizations: view direction for diffuse components and reflection direction for specular components. This dual spherical harmonic (SH) decomposition, enables realistic rendering of reflective surfaces while maintaining the computational efficiency of Gaussian splatting. To address geometric fidelity challenges, our method incorporates a comprehensive optimization strategy including silhouette-guided geometric constraints for sharp opacity boundaries, HDR saturation loss for handling bright regions in high dynamic range environments, and multi-faceted normal vector optimization with photometric and physics-based supervision. Experimental validation on the DiLiGenT-MV benchmark demonstrates superior performance compared to existing methods, with significant improvements in PSNR, SSIM, and LPIPS metrics while achieving fast optimisation and real-time rendering performance suitable for interactive applications.