A point cloud is a type of data structure used to represent a collection of multi-dimensional points, including three-dimensional data. The contained points typically represent the X,Y, and Z geometric coordinates of a sample surface. The developments of these points are often intended to represent the exterior surface of a specific object.
How are They Created?
Point clouds are generated using3D laser scanners, such as those used in the mining industry. To do this, the scanner measures a large number of points on the surface of an object using an optimized scan pattern, specific to the manufacturer and typically chosen based on application method. The point cloud created during this process then represents the collection of points previously measured– this can be in ‘raw’ form, or filtered/parsed in such a way to support the given use case.
How are They Used?
While point clouds by themselves can be inspected and analyzed, they are not often usable in most 3D applications. Typically, when a point cloud has been created, it is converted into a polygon mesh or triangle model, CAD model, or NURBS model through a process known as surface reconstruction (often referred to as ‘meshing’ or ‘triangulating’ in the mining industry).
There are many uses and benefits to working with 3D point clouds. For example, one application in which point clouds are directly usable is industrial inspection using industrial computed tomography. The point cloud of a manufactured part can be aligned to a CAD model (or even another point cloud), and compared to check for differences. These differences can be displayed as color maps that give a visual indicator of the deviation between the manufactured part and the CAD model. Geometric dimensions and tolerances can also be extracted directly from the point cloud.
Point clouds can also be used to represent volumetric data used, for example, in medical imaging. Using point clouds multi-sampling and data compression are achieved.
In the geographic information system, point clouds are one of the sources to make digital elevation model of the terrain. The point clouds are also employed in order to generate 3D models of urban environments.