Gaussian Splatting for Facade Orthophoto Generation – Comparison with MVS and TLS

Abstract. The notion of radiance fields is a very recent topic which has gained much traction in the past couple of years. Among some of the well known techniques, 3D Gaussian splatting (3DGS) seems to generate promising results in terms of 3D reconstruction. In the domain of heritage documentation, orthophotos are a standard product usually generated from photogrammetry by projecting image pixels into a 3D surface created from depth maps or point clouds. In this paper we investigate the possibility to substitute the conventional method for 3D surface generation, either terrestrial laser scanning (TLS) or multi-view stereo (MVS), with 3DGS. The paper will attempt to answer two questions: (1) whether this novel method is a viable solution for orthophoto generation within the heritage documentation context, and (2) at what point is 3DGS worth the time and effort to reach an acceptable orthophoto when compared to conventional methods. To do this, we perform multiple analysis on both the geometric quality of point clouds and the orthophotos themselves, using conventional TLS data as our reference. Our results indicate that 3DGS is not only promising, but indeed a viable alternative to conventional MVS with a potential gain of processing time between 12% up to 33% to reach a comparable quality. In the scenarios tested, both of these gains came with an average point cloud standard deviation of 2 cm.