
dxcorr(1)                    Khoros                     dxcorr(1)

PROGRAM
     dxcorr - Cross-correlation sequence of 1-D signals.

SYNTAX
     dxcorr

     -i1            input first file (xviff file)

     -i2            input second file (xviff file)

     -o             resulting output file (xviff file)

     [-s]           number of points for cross-correlation
                    sequence

     [-j]           define arithmetic on data

     [-d]           data processing direction (0 = down vectors,
                    1 = across bands)

     [-g]           type of cross-correlation file to be created:
                    0 (choose biased cross-correlation estimate),
                    1 (choose unbiased cross-correlation esti-
                    mate),
                    or 2 (choose FFT based cross-correlation
                    estimate)
                       [default = 0]

     [-V]           Gives the version for dxcorr

     [-U]           Gives the usage for dxcorr

     [-P]           Prompts for command line options

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

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

DESCRIPTION
     dxcorr 1D Cross-Correlation Estimate. Generates either the
     biased, unbiased or FFT based cross-correlation estimate of
     two data sequences.  It can operate on Real and Complex
     data. If complex data, the user has the option of using com-
     plex arithmetic (vector) or real arithmetic (scalar = treat
     the real number and imaginary number independently).  NOTE:
     complex data is expected to be in rectangular (not polar)
     form.
           Both sequences must be of the same data type.
           The cross-correlation function is not a symmetric
     function.

     The number of cross-correlation points may be selected by
     the user.  This number represents the number of points to
     the right of, and including the center point.  The actual
     number of data points will be 2*s - 1, where s is the number
     of points to the right of, and including the center point.

     dxcorr does not work on explicit location data and will
     return an error when such a file is encountered.  No output
     file will be created.  dxcorr works only on VFF_TYP_FLOAT or
     VFF_TYP_COMPLEX data files.

     Input/Output Files
     The input files must be of type VFF_TYP_FLOAT or
     VFF_TYP_COMPLEX.  The output file returned will be of size
     specified by the user.
     *********************************************************************

     The cross-correlation default option is the -g (biased esti-
     mate = 0) option.  When this option is selected, dxcorr cal-
     culates the biased cross-correlation estimate.

     Process direction
     Data can be processed with either band or vector orientation
     (-d option).  The default data processing direction is in
     the vector direction (-d = 0).  This means that data stored
     in multiband format will be processed as a set pixel loca-
     tion.  The direction of processing can be changed so that
     each band is processed as a signal (instead of each vector
     being a signal) by setting the -d option to 1.

REQUIRED ARGUMENTS
     -i1    type: infile
            desc: input first file (xviff file)

     -i2    type: infile
            desc: input second file (xviff file)

     -o     type: outfile
            desc: resulting output file (xviff file)

OPTIONAL ARGUMENTS
     -s     type: integer
            desc: number of points for cross-correlation sequence
            default: 256
            bounds: value > 0

     -j     type: boolean
            desc: define arithmetic on data
            default: true

     -d     type: boolean
            desc: data processing direction (0 = down vectors, 1
            = across bands)
            default: true

     -g     type: integer
            desc: type of cross-correlation file to be created
            allowed values:
            0 (choose biased cross-correlation estimate),
            1 (choose unbiased cross-correlation estimate),
            or 2 (choose FFT based cross-correlation estimate)

EXAMPLES
     dxcorr -i1 input_file1 -i2 input_file2 -o biased_file -s 200
     Will return a file containing 200 points of a biased cross-
     correlation estimate of the input files.  The data process-
     ing direction is in the vector direction.

     dxcorr -i1 input_file1 -i2 input_file2 -o unbiased_file -s
     512 -g 1 -j 1
     Will return a file containing 512 points of an unbiased
     cross-correlation estimate of the input files.  The data
     processing direction is in the bands direction.

SEE ALSO
     intro(1), verror(3), vgparms(3), vutils(3), ldxcorr(3)
     dacorr(1), ldacorr(3)

RESTRICTIONS
     dxcorr will operate on float and complex data only.

COPYRIGHT
     Copyright 1992, University of New Mexico.  All rights
     reserved.

Khoros                    Release: 1.0                          1

