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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)