SIFTKeypoint detects the Scale Invariant Feature Transform keypoints for a given point cloud dataset containing points and intensity. This implementation adapts the original algorithm from images to point clouds. More...
#include <sift_keypoint.h>
Public Types | |
| typedef Keypoint< PointInT, PointOutT >::KdTree | KdTree |
| typedef Keypoint< PointInT, PointOutT >::PointCloudIn | PointCloudIn |
| typedef Keypoint< PointInT, PointOutT >::PointCloudOut | PointCloudOut |
Public Member Functions | |
| void | setMinimumContrast (float min_contrast) |
| Provide a threshold to limit detection of keypoints without sufficient contrast. | |
| void | setScales (float min_scale, int nr_octaves, int nr_scales_per_octave) |
| Specify the range of scales over which to search for keypoints. | |
| SIFTKeypoint () | |
| Empty constructor. | |
Protected Member Functions | |
| void | detectKeypoints (PointCloudOut &output) |
| Detect the SIFT keypoints for a set of points given in setInputCloud () using the spatial locator in setSearchMethod (). | |
| bool | initCompute () |
| This method should get called before starting the actual computation. | |
Private Member Functions | |
| void | computeScaleSpace (const PointCloudIn &input, KdTree &tree, const std::vector< float > &scales, Eigen::MatrixXf &diff_of_gauss) |
| Compute the difference-of-Gaussian (DoG) scale space for the given input and scales. | |
| void | detectKeypointsForOctave (const PointCloudIn &input, KdTree &tree, float base_scale, int nr_scales_per_octave, PointCloudOut &output) |
| Detect the SIFT keypoints for a given point cloud for a single octave. | |
| void | findScaleSpaceExtrema (const PointCloudIn &input, KdTree &tree, const Eigen::MatrixXf &diff_of_gauss, std::vector< int > &extrema_indices, std::vector< int > &extrema_scales) |
| Find the local minima and maxima in the provided difference-of-Gaussian (DoG) scale space. | |
Private Attributes | |
| SIFTKeypointFieldSelector < PointInT > | getFieldValue_ |
| float | min_contrast_ |
| The minimum contrast required for detection. | |
| float | min_scale_ |
| The standard deviation of the smallest scale in the scale space. | |
| int | nr_octaves_ |
| The number of octaves (i.e. doublings of scale) over which to search for keypoints. | |
| int | nr_scales_per_octave_ |
| The number of scales to be computed for each octave. | |
| std::vector < sensor_msgs::PointField > | out_fields_ |
| The list of fields present in the output point cloud data. | |
| int | scale_idx_ |
| Set to a value different than -1 if the output cloud has a "scale" field and we have to save the keypoints scales. | |
Detailed Description
template<typename PointInT, typename PointOutT>
class pcl::SIFTKeypoint< PointInT, PointOutT >
SIFTKeypoint detects the Scale Invariant Feature Transform keypoints for a given point cloud dataset containing points and intensity. This implementation adapts the original algorithm from images to point clouds.
For more information about the image-based SIFT interest operator, see:
David G. Lowe, "Distinctive image features from scale-invariant keypoints," International Journal of Computer Vision, 60, 2 (2004), pp. 91-110.
Definition at line 94 of file sift_keypoint.h.
Member Typedef Documentation
| typedef Keypoint<PointInT, PointOutT>::KdTree pcl::SIFTKeypoint< PointInT, PointOutT >::KdTree |
Reimplemented from pcl::Keypoint< PointInT, PointOutT >.
Definition at line 99 of file sift_keypoint.h.
| typedef Keypoint<PointInT, PointOutT>::PointCloudIn pcl::SIFTKeypoint< PointInT, PointOutT >::PointCloudIn |
Reimplemented from pcl::Keypoint< PointInT, PointOutT >.
Definition at line 97 of file sift_keypoint.h.
| typedef Keypoint<PointInT, PointOutT>::PointCloudOut pcl::SIFTKeypoint< PointInT, PointOutT >::PointCloudOut |
Reimplemented from pcl::Keypoint< PointInT, PointOutT >.
Definition at line 98 of file sift_keypoint.h.
Constructor & Destructor Documentation
| pcl::SIFTKeypoint< PointInT, PointOutT >::SIFTKeypoint | ( | ) | [inline] |
Empty constructor.
Definition at line 109 of file sift_keypoint.h.
Member Function Documentation
| void pcl::SIFTKeypoint< PointInT, PointOutT >::computeScaleSpace | ( | const PointCloudIn & | input, |
| KdTree & | tree, | ||
| const std::vector< float > & | scales, | ||
| Eigen::MatrixXf & | diff_of_gauss | ||
| ) | [private] |
Compute the difference-of-Gaussian (DoG) scale space for the given input and scales.
- Parameters:
-
input the point cloud for which the DoG scale space will be computed tree a k-D tree of the points in input scales a vector containing the scales over which to compute the DoG scale space diff_of_gauss the resultant DoG scale space (in a number-of-points by number-of-scales matrix)
Definition at line 207 of file sift_keypoint.hpp.
| void pcl::SIFTKeypoint< PointInT, PointOutT >::detectKeypoints | ( | PointCloudOut & | output | ) | [protected, virtual] |
Detect the SIFT keypoints for a set of points given in setInputCloud () using the spatial locator in setSearchMethod ().
- Parameters:
-
output the resultant cloud of keypoints
Implements pcl::Keypoint< PointInT, PointOutT >.
Definition at line 98 of file sift_keypoint.hpp.
| void pcl::SIFTKeypoint< PointInT, PointOutT >::detectKeypointsForOctave | ( | const PointCloudIn & | input, |
| KdTree & | tree, | ||
| float | base_scale, | ||
| int | nr_scales_per_octave, | ||
| PointCloudOut & | output | ||
| ) | [private] |
Detect the SIFT keypoints for a given point cloud for a single octave.
- Parameters:
-
input the point cloud to detect keypoints in tree a k-D tree of the points in input base_scale the first (smallest) scale in the octave nr_scales_per_octave the number of scales to to compute output the resultant point cloud containing the SIFT keypoints
Definition at line 152 of file sift_keypoint.hpp.
| void pcl::SIFTKeypoint< PointInT, PointOutT >::findScaleSpaceExtrema | ( | const PointCloudIn & | input, |
| KdTree & | tree, | ||
| const Eigen::MatrixXf & | diff_of_gauss, | ||
| std::vector< int > & | extrema_indices, | ||
| std::vector< int > & | extrema_scales | ||
| ) | [private] |
Find the local minima and maxima in the provided difference-of-Gaussian (DoG) scale space.
- Parameters:
-
input the input point cloud tree a k-D tree of the points in input diff_of_gauss the DoG scale space (in a number-of-points by number-of-scales matrix) extrema_indices the resultant vector containing the point indices of each keypoint extrema_scales the resultant vector containing the scale indices of each keypoint
Definition at line 258 of file sift_keypoint.hpp.
| bool pcl::SIFTKeypoint< PointInT, PointOutT >::initCompute | ( | ) | [protected, virtual] |
This method should get called before starting the actual computation.
Internally, initCompute() does the following:
- checks if an input dataset is given, and returns false otherwise
- checks whether a set of input indices has been given. Returns true if yes.
- if no input indices have been given, a fake set is created, which will be used until:
- either a new set is given via setIndices(), or
- a new cloud is given that has a different set of points. This will trigger an update on the set of fake indices
Reimplemented from pcl::Keypoint< PointInT, PointOutT >.
Definition at line 64 of file sift_keypoint.hpp.
| void pcl::SIFTKeypoint< PointInT, PointOutT >::setMinimumContrast | ( | float | min_contrast | ) |
Provide a threshold to limit detection of keypoints without sufficient contrast.
- Parameters:
-
min_contrast the minimum contrast required for detection
Definition at line 57 of file sift_keypoint.hpp.
| void pcl::SIFTKeypoint< PointInT, PointOutT >::setScales | ( | float | min_scale, |
| int | nr_octaves, | ||
| int | nr_scales_per_octave | ||
| ) |
Specify the range of scales over which to search for keypoints.
- Parameters:
-
min_scale the standard deviation of the smallest scale in the scale space nr_octaves the number of octaves (i.e. doublings of scale) to compute nr_scales_per_octave the number of scales to compute within each octave
Definition at line 47 of file sift_keypoint.hpp.
Member Data Documentation
SIFTKeypointFieldSelector<PointInT> pcl::SIFTKeypoint< PointInT, PointOutT >::getFieldValue_ [private] |
Definition at line 197 of file sift_keypoint.h.
float pcl::SIFTKeypoint< PointInT, PointOutT >::min_contrast_ [private] |
The minimum contrast required for detection.
Definition at line 188 of file sift_keypoint.h.
float pcl::SIFTKeypoint< PointInT, PointOutT >::min_scale_ [private] |
The standard deviation of the smallest scale in the scale space.
Definition at line 179 of file sift_keypoint.h.
int pcl::SIFTKeypoint< PointInT, PointOutT >::nr_octaves_ [private] |
The number of octaves (i.e. doublings of scale) over which to search for keypoints.
Definition at line 182 of file sift_keypoint.h.
int pcl::SIFTKeypoint< PointInT, PointOutT >::nr_scales_per_octave_ [private] |
The number of scales to be computed for each octave.
Definition at line 185 of file sift_keypoint.h.
std::vector<sensor_msgs::PointField> pcl::SIFTKeypoint< PointInT, PointOutT >::out_fields_ [private] |
The list of fields present in the output point cloud data.
Definition at line 195 of file sift_keypoint.h.
int pcl::SIFTKeypoint< PointInT, PointOutT >::scale_idx_ [private] |
Set to a value different than -1 if the output cloud has a "scale" field and we have to save the keypoints scales.
Definition at line 192 of file sift_keypoint.h.
The documentation for this class was generated from the following files: