#include <gandalf/vision/harris_corner.h>
The Harris corner detector [#!Harris:Stephens:ALVEY88!#] computes the
locally averaged moment matrix computed from the image gradients, and
then combines the eigenvalues of the moment matrix to compute a corner
``strength'', of which maximum values indicate the corner positions.
Here is an example code fragment using the Harris corner detector.
Gan_Image *pImage; /* declare image from which corners will be computed */
Gan_Mask1D *pFilter; /* convolution mask */
Gan_CornerFeatureMap CornerMap; /* declare corner map */
/* ... fill image ... */
/* initialise corner map */
gan_corner_feature_map_form ( &CornerMap,
1000 ); /* initial limit on number of corners */
/* create convolution mask */
pFilter = gan_gauss_mask_new ( GAN_FLOAT, 1.0, 9, 1.0, NULL );
/* apply Harris corner detector */
gan_harris_corner_q ( pImage, /* input image */
NULL, /* or binary mask of pixels to be processed */
NULL, NULL, /* or image pre-smoothing masks */
pFilter, pFilter, /* gradient smoothing */
0.04, /* kappa used in computing corner strength */
0.04, /* corner strength threshold */
NULL, /* or affine coordinate transformation */
0, /* status value to assign to each corner */
NULL, /* or pointer to camera structure defining
distortion model */
NULL, /* or parameters of local feature map */
&CornerMap ); /* result corner map */
/* free convolution mask and corner map */
gan_mask1D_free ( pFilter );
gan_corner_feature_map_free ( &CornerMap );