6DGS: 6D Pose Estimation from a Single Image and a 3D Gaussian Splatting Model

Matteo Bortolon*, Theodore Tsesmelis, Stuart James, Fabio Poiesi, Alessio Del Bue ;

"We propose to estimate the camera pose of a target RGB image given a 3D Gaussian Splatting (3DGS) model representing the scene. avoids the iterative process typical of analysis-by-synthesis methods (iNeRF) that also require an initialization of the camera pose in order to converge. Instead, our method estimates a 6DoF pose by inverting the 3DGS rendering process. Starting from the object surface, we define a radiant that uniformly generates rays departing from each ellipsoid that parameterize the 3DGS model. Each ray is associated with the rendering parameters of each ellipsoid, which in turn is used to obtain the best bindings between the target image pixels and the cast rays. These pixel-ray bindings are then ranked to select the best scoring bundle of rays, which their intersection provides the camera center and, in turn, the camera rotation. The proposed solution obviates the necessity of an “a priori” pose for initialization, and it solves 6DoF pose estimation in closed form, without the need for iterations. Moreover, compared to the existing Novel View Synthesis (NVS) baselines for pose estimation, can improve the overall average rotational accuracy by 12% and translation accuracy by 22% on real scenes, despite not requiring any initialization pose. At the same time, our method operates near real-time, reaching 15f ps on consumer hardware. Project page: https://mbortolon97.github.io/6dgs/ Corresponding author: mbortolon@fbk.eu"