
vtexture(1)                  Khoros                   vtexture(1)

PROGRAM
     vtexture - Texture feature extraction using LAW metrics.

SYNTAX
     vtexture

     -i             input image filename

     -o             output image filename

     [-L5L5]        choose texture kernel

     [-L5E5]        choose texture kernel

     [-L5S5]        choose texture kernel

     [-L5W5]        choose texture kernel

     [-L5R5]        choose texture kernel

     [-E5L5]        choose texture kernel

     [-E5E5]        choose texture kernel

     [-E5S5]        choose texture kernel

     [-E5W5]        choose texture kernel

     [-E5R5]        choose texture kernel

     [-S5L5]        choose texture kernel

     [-S5E5]        choose texture kernel

     [-S5S5]        choose texture kernel

     [-S5W5]        choose texture kernel

     [-S5R5]        choose texture kernel

     [-W5L5]        choose texture kernel

     [-W5E5]        choose texture kernel

     [-W5S5]        choose texture kernel

     [-W5W5]        choose texture kernel

     [-W5R5]        choose texture kernel

     [-R5L5]        choose texture kernel

     [-R5E5]        choose texture kernel

     [-R5S5]        choose texture kernel

     [-R5W5]        choose texture kernel

     [-R5R5]        choose texture kernel

     [-V]           Gives the version for vtexture

     [-U]           Gives the usage for vtexture

     [-P]           Prompts for command line options

     [-A [file1]]   Creates the answer file called vtexture.ans
                    or file1

     [-a [file1]]   Uses vtexture.ans or file1 as the answer file

DESCRIPTION
     vtexture will extract texture features from an image by con-
     volving the original image with a spatial filter.  The spa-
     tial filters are comprised of 5 x 5 kernels derived from
     center-weighted vectors defined by the LAWS texture measure.

     The five center-weighted vectors are:

              L5 = [ 1  4  6  4  1]
              E5 = [-1 -2  0  2  1]
              S5 = [-1  0  2  0 -1]
              W5 = [-1  2  0 -2  1]
              R5 = [ 1 -4  6 -4  1]

     Each 5 x 5 kernel is derived from multiplying a particular
     combination of two of the above vectors.  This results in 25
     possible 5 x 5 kernels.  Note that 10 of the kernels are
     formed by taking the transpose.  For example, L5E5 is a 5 x
     5 kernel formed by multiplying the vectors, L5 with E5.
     It's transpose is E5L5, and is similarly formed by multiply-
     ing the vectors, E5 with L5.  One of these kernels is more
     sensitive to horizontal changes in texture, while the other
     is sensitive to vertical changes in texture.

     The sum of the elements of each kernel is zero, which
     results in the output image having a mean of zero.  There-
     fore the relevant texture information is contained in the
     image variance of the microtexture features.  The LAW ker-
     nels were designed to be sensitive to structures such as
     edges, ripples, and spots.

     Choosing which kernel to use will depend on the nature of
     the texture of interest, and will require trial and error to
     decide which produces the feature with the most discriminat-
     ing power.  In general, if a texture kernel of say, L5S5 is
     used, one may also want to use its transpose, S5L5 for cer-
     tain types of quasiperiodic variations commonly found in
     textured images.

     Once the texture features are extracted, macrostatistical
     estimates may be obtained using a larger window size (eg. 15
     x 15 or 31 x 31).  Some useful statistics may be the vari-
     ance or the absolute average.  Such features of the texture
     filtered image were referred to as texture energy measures
     by K.I. LAWS.

     References -

     K. I. Laws, "Rapid texture identification" Proc. SPIE, vol.
     238, pp.376-380, 1980.

     J. Y. Hsiao, and A. A. Sawchuk, "Supervised textured image
     segmentation using feature smoothing and probabilistic
     relaxation techniques" IEEE Trans.  Pattern Anal. Machine
     Intell., vol. 11, No. 12, pp 1279-1292, 1989.

REQUIRED ARGUMENTS
     -i     type: infile
            desc: input image filename

     -o     type: outfile
            desc: output image filename

OPTIONAL ARGUMENTS
     -L5L5  type: boolean
            desc: choose texture kernel
            default: true

     -L5E5  type: boolean
            desc: choose texture kernel
            default: false

     -L5S5  type: boolean
            desc: choose texture kernel
            default: false

     -L5W5  type: boolean
            desc: choose texture kernel
            default: false

     -L5R5  type: boolean
            desc: choose texture kernel
            default: false

     -E5L5  type: boolean
            desc: choose texture kernel
            default: false

     -E5E5  type: boolean
            desc: choose texture kernel
            default: false

     -E5S5  type: boolean
            desc: choose texture kernel
            default: false

     -E5W5  type: boolean
            desc: choose texture kernel
            default: false

     -E5R5  type: boolean
            desc: choose texture kernel
            default: false

     -S5L5  type: boolean
            desc: choose texture kernel
            default: false

     -S5E5  type: boolean
            desc: choose texture kernel
            default: false

     -S5S5  type: boolean
            desc: choose texture kernel
            default: false

     -S5W5  type: boolean
            desc: choose texture kernel
            default: false

     -S5R5  type: boolean
            desc: choose texture kernel
            default: false

     -W5L5  type: boolean
            desc: choose texture kernel
            default: false

     -W5E5  type: boolean
            desc: choose texture kernel
            default: false

     -W5S5  type: boolean
            desc: choose texture kernel
            default: false

     -W5W5  type: boolean
            desc: choose texture kernel
            default: false

     -W5R5  type: boolean
            desc: choose texture kernel
            default: false

     -R5L5  type: boolean
            desc: choose texture kernel
            default: false

     -R5E5  type: boolean
            desc: choose texture kernel
            default: false

     -R5S5  type: boolean
            desc: choose texture kernel
            default: false

     -R5W5  type: boolean
            desc: choose texture kernel
            default: false

     -R5R5  type: boolean
            desc: choose texture kernel
            default: false

EXAMPLES
SEE ALSO
     intro(1), verror(3), vgparms(3), vutils(3), lvtexture(3)
     vspatial(1)

RESTRICTIONS
     vtexture will operate on images of data storage type BYTE or
     FLOAT.  The output image will be either an INTEGER or FLOAT
     image, depending on the data type of the input image.  If
     the input image is of data type BYTE or SHORT, then it is
     converted up to an INTEGER image.  If the input image is of
     data type FLOAT, then the resulting output image will be of
     data type FLOAT.

COPYRIGHT
     Copyright 1991, University of New Mexico.  All rights
     reserved.

Khoros                    Release: 1.0                          1

