A point cloud is a set of data points in space. Point clouds are generally produced by 3D scanners, which measure a large number of points on the external surfaces of objects around them. As the output of 3D scanning processes, point clouds are used for many purposes, including to create 3D CAD models for manufactured parts, for metrology and quality inspection, and for a multitude of visualization, animation, rendering and mass customization applications.
Video Point cloud
Alignment and registration
Point clouds are often aligned with 3D models or with other point clouds, a process known as point set registration.
For industrial metrology or inspection using industrial computed tomography, the point cloud of a manufactured part can be aligned to an existing model and compared to check for differences. Geometric dimensions and tolerances can also be extracted directly from the point cloud.
Maps Point cloud
Conversion to 3D surfaces
While point clouds can be directly rendered and inspected, point clouds are often converted to polygon mesh or triangle mesh models, NURBS surface models, or CAD models through a process commonly referred to as surface reconstruction.
There are many techniques for converting a point cloud to a 3D surface. Some approaches, like Delaunay triangulation, alpha shapes, and ball pivoting, build a network of triangles over the existing vertices of the point cloud, while other approaches convert the point cloud into a volumetric distance field and reconstruct the implicit surface so defined through a marching cubes algorithm.
In geographic information systems, point clouds are one of the sources used to make digital elevation model of the terrain. They are also used to generate 3D models of urban environments.
Point clouds can also be used to represent volumetric data, as is sometimes done in medical imaging. Using point clouds, multi-sampling and data compression can be achieved.
See also
- Euclideon, a 3D graphics engine which makes use of a point cloud search algorithm to render images.
- MeshLab, an open source tool for managing point clouds and converting them into 3D triangular meshes;
- CloudCompare, an open source tool for viewing, editing and processing high density 3D point clouds
- PCL (Point Cloud Library), a comprehensive BSD open source library for n-D Point Clouds and 3D geometry processing
- PDAL, an open source library for point cloud data translation and format abstraction
- List of programs for point cloud processing
References
Source of the article : Wikipedia
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