imgfeatures.h File Reference

Functions and structures for dealing with image features. More...

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Detailed Description

Functions and structures for dealing with image features.

Copyright (C) 2006 Rob Hess <hess@eecs.oregonstate.edu>

Version:

1.1.1-20070119

Definition in file imgfeatures.h.

Go to the source code of this file.

Classes
struct	feature
	Structure to represent an affine invariant image feature. More...
Defines
#define	FEATURE_OXFD_COLOR   CV_RGB(255,255,0)
#define	FEATURE_LOWE_COLOR   CV_RGB(255,0,255)
#define	FEATURE_MAX_D   128
	max feature descriptor length
Enumerations
enum	feature_type { FEATURE_OXFD, FEATURE_LOWE }
	FEATURE_OXFD FEATURE_LOWE.
enum	feature_match_type { FEATURE_FWD_MATCH, FEATURE_BCK_MATCH, FEATURE_MDL_MATCH }
	FEATURE_FWD_MATCH FEATURE_BCK_MATCH FEATURE_MDL_MATCH.
Functions
int	import_features (char *filename, int type, struct feature **feat)
	Reads image features from file.
int	export_features (char *filename, struct feature *feat, int n)
	Exports a feature set to a file formatted depending on the type of features, as specified in the feature struct's type field.
void	draw_features (IplImage *img, struct feature *feat, int n)
	Displays a set of features on an image.
double	descr_dist_sq (struct feature *f1, struct feature *f2)
	Calculates the squared Euclidian distance between two feature descriptors.

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Function Documentation

double descr_dist_sq	(	struct feature *	f1,
		struct feature *	f2
	)

Calculates the squared Euclidian distance between two feature descriptors.

Parameters:

f1	first feature
f2	second feature

Returns:

Returns the squared Euclidian distance between the descriptors of f1 and f2.

void draw_features	(	IplImage *	img,
		struct feature *	feat,
		int	n
	)

Displays a set of features on an image.

Parameters:

img	image on which to display features
feat	array of Oxford-type features
n	number of features

int export_features	(	char *	filename,
		struct feature *	feat,
		int	n
	)

Exports a feature set to a file formatted depending on the type of features, as specified in the feature struct's type field.

Parameters:

filename	name of file to which to export features
feat	feature array
n	number of features

Returns:

Returns 0 on success or 1 on error

int import_features	(	char *	filename,
		int	type,
		struct feature **	feat
	)

Reads image features from file.

The file should be formatted either as from the code provided by the Visual Geometry Group at Oxford or from the code provided by David Lowe.

Parameters:

filename	location of a file containing image features
type	determines how features are input. If type is FEATURE_OXFD, the input file is treated as if it is from the code provided by the VGG at Oxford: http://www.robots.ox.ac.uk:5000/~vgg/research/affine/index.html If type is FEATURE_LOWE, the input file is treated as if it is from David Lowe's SIFT code: http://www.cs.ubc.ca/~lowe/keypoints
feat	pointer to an array in which to store imported features

Returns:

Returns the number of features imported from filename or -1 on error