#2325: Normalization for the probability matrices in r.texture.
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Reporter: DmitryKolesov | Owner: grass-dev@…
Type: defect | Status: new
Priority: normal | Milestone: 6.4.4
Component: Default | Version: unspecified
Keywords: | Platform: Unspecified
Cpu: Unspecified |
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I think there is an issue with the normalization procedure in h_measure.c
(lines 156--168):
http://trac.osgeo.org/grass/browser/grass/branches/releasebranch_6_4/raster/r.texture/h_measure.c#L156
The goal of the normalization is to calculate the probability matrices
(see Haralick, R.M., K. Shanmugam, and I. Dinstein (1973). Textural
features for image classification. IEEE Transactions on Systems, Man, and
Cybernetics, SMC-3(6), page 613). So the normalizing constants are the
sums of the matrix elements (see matrix P_matrix0, P_matrix45, P_matrix90,
P_matrix135).
The normalizing constants R0, R45, R90 are good for the default distance
parameter (d==1), but if d>1 then the constants are wrong.
I think the next code for lines 157--159
{{{
R0 = 2 * rows * (cols - d);
R45 = 2 * (rows - d) * (cols - d);
R90 = 2 * (rows - d) * cols;
}}}
will fix the issue.
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Ticket URL: <http://trac.osgeo.org/grass/ticket/2325>
GRASS GIS <http://grass.osgeo.org>
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