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Classes | Macros | Functions
sift.h File Reference
#include <mrpt/otherlibs/do_opencv_includes.h>
Include dependency graph for sift.h:

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Classes

struct  detection_data
 holds feature data relevant to detection More...
 

Macros

#define SIFT_INTVLS   3
 default number of sampled intervals per octave More...
 
#define SIFT_SIGMA   1.6
 default sigma for initial gaussian smoothing More...
 
#define SIFT_IMG_DBL   1
 default threshold on keypoint contrast |D(x)| More...
 
#define SIFT_DESCR_WIDTH   4
 default width of descriptor histogram array More...
 
#define SIFT_DESCR_HIST_BINS   8
 default number of bins per histogram in descriptor array More...
 
#define SIFT_INIT_SIGMA   0.5
 
#define SIFT_IMG_BORDER   5
 
#define SIFT_MAX_INTERP_STEPS   5
 
#define SIFT_ORI_HIST_BINS   36
 
#define SIFT_ORI_SIG_FCTR   1.5
 
#define SIFT_ORI_RADIUS   3.0 * SIFT_ORI_SIG_FCTR
 
#define SIFT_ORI_SMOOTH_PASSES   2
 
#define SIFT_ORI_PEAK_RATIO   0.8
 
#define SIFT_DESCR_SCL_FCTR   3.0
 
#define SIFT_DESCR_MAG_THR   0.2
 
#define SIFT_INT_DESCR_FCTR   512.0
 
#define feat_detection_data(f)   ( (struct detection_data*)(f->feature_data) )
 

Functions

int sift_features (IplImage *img, struct feature **feat)
 Finds SIFT features in an image using default parameter values. More...
 
int _sift_features (IplImage *img, struct feature **feat, int intvls, double sigma, double contr_thr, int curv_thr, int img_dbl, int descr_width, int descr_hist_bins)
 Finda SIFT features in an image using user-specified parameter values. More...
 

Macro Definition Documentation

#define feat_detection_data (   f)    ( (struct detection_data*)(f->feature_data) )

Definition at line 94 of file sift.h.

Referenced by mrpt::vision::CFeatureExtraction::my_scale_space_extrema().

#define SIFT_DESCR_HIST_BINS   8

default number of bins per histogram in descriptor array

Definition at line 58 of file sift.h.

Referenced by mrpt::vision::CFeatureExtraction::extractFeaturesSIFT(), and mrpt::vision::CFeatureExtraction::internal_computeSiftDescriptors().

#define SIFT_DESCR_MAG_THR   0.2

Definition at line 88 of file sift.h.

#define SIFT_DESCR_SCL_FCTR   3.0

Definition at line 85 of file sift.h.

#define SIFT_DESCR_WIDTH   4

default width of descriptor histogram array

Definition at line 55 of file sift.h.

Referenced by mrpt::vision::CFeatureExtraction::extractFeaturesSIFT(), and mrpt::vision::CFeatureExtraction::internal_computeSiftDescriptors().

#define SIFT_IMG_BORDER   5

Definition at line 64 of file sift.h.

#define SIFT_IMG_DBL   1

default threshold on keypoint contrast |D(x)|

default threshold on keypoint ratio of principle curvatures double image size before pyramid construction?

Definition at line 52 of file sift.h.

Referenced by mrpt::vision::CFeatureExtraction::extractFeaturesSIFT(), and mrpt::vision::CFeatureExtraction::internal_computeSiftDescriptors().

#define SIFT_INIT_SIGMA   0.5

Definition at line 61 of file sift.h.

#define SIFT_INT_DESCR_FCTR   512.0

Definition at line 91 of file sift.h.

#define SIFT_INTVLS   3

default number of sampled intervals per octave

Definition at line 40 of file sift.h.

Referenced by mrpt::vision::CFeatureExtraction::extractFeaturesSIFT(), and mrpt::vision::CFeatureExtraction::internal_computeSiftDescriptors().

#define SIFT_MAX_INTERP_STEPS   5

Definition at line 67 of file sift.h.

#define SIFT_ORI_HIST_BINS   36

Definition at line 70 of file sift.h.

#define SIFT_ORI_PEAK_RATIO   0.8

Definition at line 82 of file sift.h.

#define SIFT_ORI_RADIUS   3.0 * SIFT_ORI_SIG_FCTR

Definition at line 76 of file sift.h.

#define SIFT_ORI_SIG_FCTR   1.5

Definition at line 73 of file sift.h.

#define SIFT_ORI_SMOOTH_PASSES   2

Definition at line 79 of file sift.h.

#define SIFT_SIGMA   1.6

Function Documentation

int _sift_features ( IplImage *  img,
struct feature **  feat,
int  intvls,
double  sigma,
double  contr_thr,
int  curv_thr,
int  img_dbl,
int  descr_width,
int  descr_hist_bins 
)

Finda SIFT features in an image using user-specified parameter values.

All detected features are stored in the array pointed to by feat.

Parameters
imgthe image in which to detect features
feata pointer to an array in which to store detected features
intvlsthe number of intervals sampled per octave of scale space
sigmathe amount of Gaussian smoothing applied to each image level before building the scale space representation for an octave
contr_thra threshold on the value of the scale space function $\left|D(\hat{x})\right|$, where $\hat{x}$ is a vector specifying feature location and scale, used to reject unstable features; assumes pixel values in the range [0, 1]
curv_thrthreshold on a feature's ratio of principle curvatures used to reject features that are too edge-like
img_dblshould be 1 if image doubling prior to scale space construction is desired or 0 if not
descr_widththe width, $n$, of the $n \times n$ array of orientation histograms used to compute a feature's descriptor
descr_hist_binsthe number of orientations in each of the histograms in the array used to compute a feature's descriptor
Returns
Returns the number of keypoints stored in feat or -1 on failure
See Also
sift_features()
int sift_features ( IplImage *  img,
struct feature **  feat 
)

Finds SIFT features in an image using default parameter values.

All detected features are stored in the array pointed to by feat.

Parameters
imgthe image in which to detect features
feata pointer to an array in which to store detected features
Returns
Returns the number of features stored in feat or -1 on failure
See Also
_sift_features()



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