A combined approach of SFM-MVS photogrammetry and reflectance transformation imaging to enhance 3D reconstructions

One of the problems that arises when applying 3D Structure from Motion and Multi-View-Stereo photogrammetry to certain heritage objects characterized by minimal surface features and monochrome textures is that the obtained 3D models have low quality and accuracy. Within such scenarios, the smallest lengths that can be measured on it with high accuracy is usually one or more orders of magnitude worse than the maximum resolution of the input photographs. Additionally, when contrasted with outputs from scanning systems, these reconstructions tend to exhibit relatively lower quality. This article presents a simple approach wherein the incorporation of normal maps acquired through Reflectance Transformation Imaging technique improves the quality and accuracy of 3D photogrammetric reconstructions (mesh + texture). This enhancement also surpasses the capabilities of some commercial structured light scanning systems and reaches values that are in the order of magnitude of the maximum resolution of the photographs used.