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CGAL::pca_estimate_normals

Definition

CGAL::pca_estimate_normals() estimates normal directions at all points of an input point set by linear least squares fitting of a plane over their k nearest neighbors. The result is an unoriented normal for each input point.

The output of the normal estimation algorithm highly depends on the k parameter. The number of neighbors controls the size of the point subset considered for plane fitting at each input point. As this parameter is application-specific we do not provide any default value. For noise-free point sets this value can be set to a small number, e.g., 18. Larger values (e.g., 30 or more) lead to smoother normal fields and are more time consuming. We thus recommend using them only for noisy data sets.

#include <CGAL/pca_estimate_normals.h>

template<typename InputIterator, typename PointPMap, typename NormalPMap, typename Kernel>
void
pca_estimate_normals ( InputIterator first,
InputIterator beyond,
PointPMap point_pmap,
NormalPMap normal_pmap,
unsigned int k,
Kernel kernel)
Estimates normal directions of the [first, beyond) range of points by linear least squares fitting of a plane over the k nearest neighbors. The output normals are randomly oriented.
Precondition: k >= 2.
Template Parameters: 
InputIterator: iterator over input points. PointPMap: is a model of boost::ReadablePropertyMap with a value_type = Point_3<Kernel>. It can be omitted if InputIterator value_type is convertible to Point_3<Kernel>. NormalPMap: is a model of boost::WritablePropertyMap with a value_type = Vector_3<Kernel>. Kernel: Geometric traits class. It can be omitted and deduced automatically from PointPMap value_type.
Parameters: 
first: iterator over the first input point. beyond: past-the-end iterator over the input points. point_pmap: property map InputIterator -> Point_3. normal_pmap: property map InputIterator -> Vector_3. k: number of neighbors. kernel: geometric traits.

See Also

CGAL::jet_estimate_normals
CGAL::mst_orient_normals

Example

See normals_example.cpp.

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CGAL Open Source Project. Release 3.7. 14 October 2010.