pgmtexture(1)                                       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).   Tex-
       tural 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. Tex-
       tural features for image  classification.   IEEE  Transac-
       tions     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 lim-
       ited.  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 Sta-
       tion, employer for hire of James Darrell McCauley.

                           22 Aug 1991                          1