**NAME**

glds, glds_features - calculate the spatial grey level difference
matrix and features on it

**SYNOPSIS**

glds image matrix xpos ypos xsize ysize dx dy
glds_features matrix

**DESCRIPTION**

**glds** creates a 256 by 1 one channel spatial grey level difference
matrix (sglds) of the box determined by the parameters (xp, yp; xs, ys)
within the vasari image file image. The matrix is written onto the
vasari image file matrix. 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 sgld 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., â€™Textural features for image classificationâ€™, 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 file.
**glds_features** calculates features on the spatial grey level difference
vasari image file matrix. The calculated features are printed in the
stderr.

**SEE ALSO**

im_glds_matrix(3X), im_glds_asm(3X), im_glds_contrast(3X),
im_glds_correlation(3X), im_glds_entropy(3X).

**COPYRIGHT**

N. Dessipris

**AUTHOR**

N. Dessipris - 27/02/1992
27 January 1992