pgmtexture

   Updated: 22 Aug 1991

NAME

   pgmtexture - calculate textural features on a portable graymap

SYNOPSIS

   pgmtexture [-d d] [pgmfile]

DESCRIPTION

   Reads a portable graymap as input. Calculates textural features based on
   spatial dependence matrices at 0, 45, 90, and 135 degrees for a distance d
   (default = 1). Textural features include:
          Angular Second Moment,
          (2) Contrast,
          Correlation,
          (4) Variance,
          Inverse Difference Moment,
          (6) Sum Average,
          (7) Sum Variance,
          Sum Entropy,
          (9) Entropy,
          (10) Difference Variance,
          (11) Difference Entropy,
          (12, 13) Information Measures of Correlation, and
          (14) Maximal Correlation Coefficient.

   Algorithm taken from:
   Haralick, R.M., K. Shanmugam, and I. Dinstein. 1973. Textural features for
   image classification. IEEE Transactions on Systems, Man, and Cybertinetics,
   SMC-3(6):610-621.

BUGS

   The program can run incredibly slow for large images (larger than 64 x 64)
   and  command line options are limited. The method for finding (14) the
   maximal correlation coefficient, which requires finding the second largest
   eigenvalue of a matrix Q, does not always converge.

REFERENCES

   IEEE Transactions on Systems, Man, and Cybertinetics, SMC-3(6):610-621.

SEE ALSO

   pgm, pnmcut

AUTHOR

   Copyright (C) 1991 by Texas Agricultural Experiment Station, employer for
   hire of James Darrell McCauley.
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