LOW-COST TERRESTRIAL PHOTOGRAMMETRY FOR 3D MODELING OF HISTORIC SITES: A CASE STUDY OF THE MARINIDS' ROYAL NECROPOLIS CITY OF FEZ, MOROCCO

One of the main factors that make the conservation of heritage by 3D modeling inaccessible, especially in developing countries, is the high cost of the terrestrial laser scanner. One alternative solution is close-range photogrammetry, which is widely used as a less-expensive technique for the documentation of historical and cultural heritage through usually high-resolution DSLR (Digital Single-Lens Reflex) cameras. While main previous works have focused on the use of such high-end cameras, this paper studies the potential of the recent entry-level phone camera for performing close-range photogrammetry as an affordable abundant tool. To achieve this goal, Marinid Royal Necropolis from the UNESCO heritage city of Fez in Morocco were photographed and 3D modeled using a smartphone and a DSLR camera. The results are compared to a set of control points (CPs) collected using a total station and then evaluated through some statistical variables. Also, to analyze the impact of several parameters, Cloud-to-Cloud (C2C) distance is calculated for each 3D model. The mean C2C distance between 3D models and CPs clouds ranged between 6.8 mm and 11.6 mm using a few CPs, and from 11 mm to 21 mm without using any CPs. All comparisons suggest that the obtained results employing the smartphone camera are comparable, stable, and even slightly more accurate than DSLR cameras in our case