Point Cloud From Drones
Point Cloud What Is It? Point Cloud is a series of data points that have been calculated via set methods and assigned torelative locations in space using a specific coordinate system, these data points can be utilised for several processes including 3D imaging for CAD Models, which may eventually be used to manufacture spare parts. Or for BIM (BuildingInformation Modeling) used for the development of new infrastructure. Point cloud is even used in land survey, digitalelevation models and topographical outputs.
Point Cloud, How Is It Achieved? Point cloud (s) can be achieved using various techniques and processed traditionallyvia photogrammetric methods which is the science of capturing images of a specific subject at different angles, whilstusing a high overlap method of up to 90%. The software recognises the common areas across the multiple images andassigns common data points to each resulting in a fluid point cloud.
Historically point cloud has been processed via the use of terrestrial active remote sensing scanners such as laser or radarwhich measure points on a subject surface resulting in deliverable 3D point cloud files. Drone technology adopts the traditional photogrammetry method when considering point cloud outputs, integratingspecific programs that allow to drone pilot to properly plan a flight allowing for sufficient front lap and side lap. whilsttaking into consideration flight height, speed of data collection, whether or not the drone should stop to capture eachimage and various other variables. All of this can affect the density, resolution, and detail within the point cloud which inturn affects any other deliverable formats derived from the point cloud process.
Point Cloud Via Drone, How Accurate Is It? Point cloud accuracy via photogrammetric techniques can be extremelyaccurate when rectified to its respective grid in the case of UK OSGB36 (Ordinance Survey Great Britain 1936) we havecarried out Geospatial survey and processed point clouds that have been within 5mm. It all depends on the quality andaccuracy of the data acquisition and position and accuracy of the assigned ground control points.
GCP’s or Ground Control Points are essential to line up the model to its respective grid and are achieved by choosing orlaying down high contrast tiles and gathering the coordinates X,Y and Z via use of a GPS rover or similar device. Thecoordinates are inputted into the chosen software and the project is then optimised resulting in absolute accuracy. IfGCP’s are not used the point cloud is still accurate although relatively within its own model.
Point Cloud and other 3D Deliverables… The benefits of adopting drone technology to either assist with your 3Dproject or as a standalone option can pay dividends and can help capitalize on specific parts of project budget. Thebenefits as always with drone technology are cost saving and time efficiency.
Deliverables that can derive from the drone processed 3D deliverables are all topographical outputs such as digital surfacemodel (DSM), Digital Elevation Model (DEM), Digital Terrain Model (DTM), Orthomosaic (Orthorectified Imagepresented as a Geotiff), Contour Files, Mesh detailing and all can be merged with terrestrial data.