Towards surveying with a smartphone

Photogrammetry is one of the most used techniques for monitoring and surveying. It is widely used in several applications and in different working conditions. Accuracy of photogrammetry reconstruction methods may change depending on the working conditions (e.g. the number of acquired images, lighting conditions, baselines between images), and it is strictly related to the success of the solution of the Structure from Motion problem. Despite its widely spread use and the ever growing improvements to the reconstruction technique, photogrammetry still does not reach the same level of reliability of laser scanning surveying techniques: significant issues may occur in photogrammetric reconstructions when in presence of lighting problems or when the object of interest is not sufficiently textured. However, it relies on the use of much cheaper tools with respect to laser scanning techniques and surveying is usually much faster. This paper aims at showing the potential improvement that can be obtained by introducing information provided by the navigation system in the 3D reconstruction algorithm: the goal is that of making the solution algorithm of the Structure from Motion problem more reliable and accurate. As a side effect, faster reconstruction is typically achieved. The technique is validated on a building using images and navigation information got from a standard smartphone.