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)