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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.

                              22 Aug 1991                    pgmtexture(1)



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