The point clouds obtained from Structure from Motion (SfM) photogrammetry need a scale factor correction if are used for quantitative evaluations as well as surface variations, volume estimates, and so on. The scale factor is required also for multitemporal models comparison. It can be achieved using homologous points, that is, points from artificial or natural elements detectable in the point clouds and just measured with independent and external measurements. In this work two different and independent approaches for the recognition, measurement and comparison of homologous points aimed at...