LightGuard: shedding light on copyright protection for relightable Gaussian splatting.

With the advent of advanced relighting techniques built upon inverse rendering and light transport modeling, users can now effortlessly adjust the lighting conditions of 3D Gaussian Splatting (3DGS) models, allowing for more flexible and immersive 3D experiences. However, this technological progress also opens the door to potential copyright infringements, as malicious users can exploit relighting to falsely claim ownership of modified 3DGS models. To mitigate these issues, we propose a robust digital watermarking mechanism to protect 3DGS models against unauthorized modifications via advanced relighting techniques. By using a base color-an intrinsic reflectance property in physically based rendering-as the cover medium for embedding watermarks, our method ensures high robustness and imperceptibility. We also introduce an Exclusive-Key (E-K) mechanism that allows only legitimate owners to extract the embedded watermarks. Experimental results demonstrate the effectiveness of our approach.