Towards Unpaired Depth Enhancement and Super-Resolution in the Wild

Depth maps captured with commodity sensors are often of low quality and resolution; these maps need to be enhanced to be used in many applications. State-of-the-art data-driven methods of depth map super-resolution rely on registered pairs of low- and high-resolution depth maps of the same scenes. Acquisition of real-world paired data requires specialized setups. Another alternative, generating low-resolution maps from high-resolution maps by subsampling, adding noise and other artificial degradation methods, does not fully capture the characteristics of real-world low-resolution images. As a consequence, supervised learning methods trained on such artificial paired data may not perform well on real-world low-resolution inputs. We consider an approach to depth map enhancement based on learning from unpaired data. While many techniques for unpaired image-to-image translation have been proposed, most are not directly applicable to depth maps. We propose an unpaired learning method for simultaneous depth enhancement and super-resolution, which is based on a learnable degradation model and surface normal estimates as features to produce more accurate depth maps. We demonstrate that our method outperforms existing unpaired methods and performs on par with paired methods on a new benchmark for unpaired learning that we developed.