SIFT
1.1.2
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Functions for detecting SIFT image features. More...
#include "cxcore.h"
Data Structures | |
struct | detection_data |
holds feature data relevant to detection More... | |
Macros | |
#define | SIFT_INTVLS 3 |
default number of sampled intervals per octave | |
#define | SIFT_SIGMA 1.6 |
default sigma for initial gaussian smoothing | |
#define | SIFT_CONTR_THR 0.04 |
default threshold on keypoint contrast |D(x)| | |
#define | SIFT_CURV_THR 10 |
default threshold on keypoint ratio of principle curvatures | |
#define | SIFT_IMG_DBL 1 |
double image size before pyramid construction? | |
#define | SIFT_DESCR_WIDTH 4 |
default width of descriptor histogram array | |
#define | SIFT_DESCR_HIST_BINS 8 |
default number of bins per histogram in descriptor array | |
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... | |
Functions for detecting SIFT image features.
For more information, refer to:
Lowe, D. Distinctive image features from scale-invariant keypoints. International Journal of Computer Vision, 60, 2 (2004), pp.91–110.
Copyright (C) 2006-2010 Rob Hess hess@ eecs .oreg onst ate.e du
Note: The SIFT algorithm is patented in the United States and cannot be used in commercial products without a license from the University of British Columbia. For more information, refer to the file LICENSE.ubc that accompanied this distribution.
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.
img | the image in which to detect features |
feat | a pointer to an array in which to store detected features; memory for this array is allocated by this function and must be freed by the caller using free(*feat) |
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.
img | the image in which to detect features |
feat | a pointer to an array in which to store detected features; memory for this array is allocated by this function and must be freed by the caller using free(*feat) |
intvls | the number of intervals sampled per octave of scale space |
sigma | the amount of Gaussian smoothing applied to each image level before building the scale space representation for an octave |
contr_thr | a threshold on the value of the scale space function ![]() ![]() |
curv_thr | threshold on a feature's ratio of principle curvatures used to reject features that are too edge-like |
img_dbl | should be 1 if image doubling prior to scale space construction is desired or 0 if not |
descr_width | the width, ![]() ![]() |
descr_hist_bins | the number of orientations in each of the histograms in the array used to compute a feature's descriptor |