Over the years, they have been used several tools to perform aerial surveys of analyzed to archaeological sites and monuments. From the plane to the balloon, the balloon to the telescopic rods, all of these tools presented problems such as costs, the reliability of the instrument, the imprecision and the limit of the relief.
Through the recent development of UAV platforms, commonly called drones, you can make the photogrammetric surveys with a high quality of metric detail.
Drone (UAVs) Per aeromobile a pilotaggio remoto, di seguito denominato «APR», si intende un mezzo aereo pilotato da un equipaggio che opera da una stazione remota di comando e controllo. Legge 14 luglio 2004, n. 178, "Disposizioni in materia di aeromobili a pilotaggio remoto delle Forze armate" What is a drone? "Drone is an aircraft without crew piloted by an pilot from a remote control."
The drones used for purposes of research and documentation can be classified generally in Multicopter and Fixed Wing Multicopter (Quadricopter, Esacopter, Octoocoptero, Helicopter) Fixed Wing (Monoala, Airplane)
Investigations made with the drone and the respective sensors used on the UAV platforms are as follows: Reflex; Compact, Action Cam for Photogrammetric surveys; Thermocamera for thermal survey, LiDAR, Multispectral and hyperspectral.
DJI Phantom Vision 2 + The drone that we use is a Multicopter-quadricopter with 4 brushless motors. It equipped with compass, altimeter, GPS, with an autonomy of about 20 minutes. It weight is 1242 grams and is equipped with a standard 14-megapixel camera that records to 1080p. It controlled through a remote control to 5.8 GHZ. By a mobile device running Android or ios you can set the camera and the camera, change the parameters, select the shooting mode (photo / video), the shooting mode, check the telemetry during the flight, the battery level, directing the two-axis gimbal and see what "sees" the drone through a WIFI connection to 2.4 GHz. It is possibile set a track for automatic waypoint so as to follow the drone an established route.
Wings Gimbal Fotocamera Smartphone/tablet Battery Joystick
How to make a photogrammetric coverage by UAV: Planning flight (choice of sensor, battery autonomy, size area to detect any hazards, geomorphology of the site to be detected, weather conditions, accuracy metric, flight altitude) Still Capture (preparation of the drone, takeoff, flight, landing, downloading data) and batting topographic (through Target or natural points) Data Processing (by software based on modern photogrammetry and computer vision) Processing final products (Orthophoto, Dem, Google KMZ)
Flight planning The first step involves identifying the area study. It determines the extent of the site, its boundaries and analyzes the entire area in full: whether or not there are any obstacles natural or man-made structures, vegetation cover and morphological study of the soil, the presence or absence of points of archaeological interest
Still Picture The second phase involves the technical preparation of the drone (battery assembly, connection to the GPS signal, etc.), take-off, flight and landing. The photos must have made a certain overlap. To obtain a better quality of the images need to perform several flights so as to minimize potential interference factors such as wind, shadows, presence of animals or people, modulated light, etc.. This phase includes the relief of the coordinates of the study area so that you can insert into the model the Ground Control Points (GCPs), as well as geo-reference the model and put it to scale automatically.
Still Picture The second phase involves the technical preparation of the drone (battery assembly, connection to the GPS signal, etc.), take-off, flight and landing. The photos must have made a certain overlap. To obtain a better quality of the images need to perform several flights so as to minimize potential interference factors such as wind, shadows, presence of animals or people, modulated light, etc.. This phase includes the relief of the coordinates of the study area so that you can insert into the model the Ground Control Points (GCPs), as well as geo-reference the model and put it to scale automatically.
Data processing The three-dimensional model is implemented by software that is based on the modern technique of Structure from Motion. The program, after having obtained the set and the camera position and the depth of the points in common between the different images, generates a cloud of points, a polygon model and the "texturing". The model created must be put "scale" through the use of GCPs (ground control points) in which are given the geographical coordinates of certain points detected to ground through surveying instruments such as total station or GPS or actual measurements of known (mainly in the case of small objects).
Processing final products The final product of the photogrammetric survey by drone is made, mainly, from 3D models from digital elevation models (DEM), the orthophoto, the KMZ file.
Processing final products The final product of the photogrammetric survey by drone is made, mainly, from 3D models from digital elevation models (DEM), the orthophoto, the KMZ file.
Processing final products The final product of the photogrammetric survey by drone is made, mainly, from 3D models from digital elevation models (DEM), the orthophoto, the KMZ file.
Thanks! Antonio Pecci (Ibam-CNR) a.pecci@ibam.cnr.it