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)