An accurate, flexible and scalable technique for multi-modal image registration is described, a technique that does not need to rely on direct feature matching and does not need to rely on precise geometric models. The methods and/or systems described in this disclosure enable the registration (fusion) of multi-modal images of a scene with a three dimensional (3D) representation of the same scene using, among other information, viewpoint data from a sensor that generated a target image, as well as 3D-GeoArcs. The registration techniques of the present disclosure may be comprised of three main steps, as shown in FIG. 1. The first main step includes forming a 3D reference model of a scene. The second main step includes estimating the 3D geospatial viewpoint of a sensor that generated a target image using 3D-GeoArcs. The third main step includes projecting the target image's data into a composite 3D scene representation.