NAME
im_cooc_matrix, im_cooc_asm, im_cooc_contrast, im_cooc_correlation,
im_cooc_entropy - calculate the co-occurrence matrix and features on it
SYNOPSIS
#include <vips/vips.h>
int im_cooc_matrix(im, m, xp, yp, xs, ys, dx, dy, sym)
IMAGE *im, *m;
int xp, yp, xs, ys;
int dx, dy;
int sym;
int im_cooc_asm(m, asmoment)
IMAGE *m;
double *asmoment;
int im_cooc_contrast(m, contrast)
IMAGE *m;
double *contrast;
int im_cooc_correlation(m, correlation)
IMAGE *m;
double *correlation;
int im_cooc_entropy(m, entropy)
IMAGE *m;
double *entropy;
DESCRIPTION
im_cooc_matrix() creates a 256 by 256 one channel co-occurrence matrix
of the box determined by the parameters (xp, yp; xs, ys) within the
image pointed by the IMAGE descriptor im. The matrix is written onto
the IMAGE descriptor m. The displacement vector is determined by (dx,
dy). The user must ensure that there is enough border pixels around
the box within im dictated by the displacement vector (dx,dy) or else
the program fails. All entries of the co-occurrence matrix are double
normalised to the number of pairs involved. This function is a direct
implementation of the paper: Haralick R. M., Shanmugan K. and Dinstein
I., ’Textural features for image classification’, IEEE Transactions on
Systems, Man, and Cybernetics, Vol. SMC-3, No 6, Nov. 1973, pp
610-621. Input im should be one band unsigned char image.
If flag sym is 1, the created co-occurrence matrix is symmetric that is
dispacement vectors (dx, dy), (-dx, -dy) create exactly the same
matrix. If sym is 0, the created co-occurrence matrix is not symmetric
that is dispacement vectors (dx, dy), (-dx, -dy) create different
matrices.
im_cooc_asm() calculates the angular second moment of the co-occurrence
matrix held by m. The result is returned into the location pointed by
asmoment.
im_cooc_contrast() calculates the contrast of the co-occurrence matrix
held by m. The result is returned into the location pointed by
contrast.
im_cooc_correlation() calculates the correlation of the co-occurrence
matrix held by m. The result is returned into the location pointed by
correlation.
im_cooc_entropy() calculates the entropy of the co-occurrence matrix
held by m. The result is returned into the location pointed by
entropy.
RETURNED VALUES
All functions returns 0 on success and -1 on error.
SEE ALSO
im_glds_matrix(3)
COPYRIGHT
N. Dessipris
AUTHOR
N. Dessipris - 2/12/1991
2 Dec 1991