“…An alternative to explicitly representing the 3D scene geometry via a 3D model is to implicitly store information about the scene in the weights of a machine learning model. Examples include scene coordinate regression techniques [9, 10, 12, 14-16, 75, 90], which regress 2D-3D matches rather than computing them via explicit descriptor matching, and absolute [34,35,48,74,93] and relative pose [3,23,37] regressors. Scene coordinate regressors achieve state-ofthe-art results for small scenes [8], but have not yet shown strong performance in more challenging scenes.…”