pgmtexture(1)             UNIX System V(22 Aug 1991)              pgmtexture(1)


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:

            (1) Angular Second Moment,
            (2) Contrast,
            (3) Correlation,
            (4) Variance,
            (5) Inverse Difference Moment,
            (6) Sum Average,
            (7) Sum Variance,
            (8) 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(5), pnmcut(1)

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









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