PGMTEXTURE

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.