
dacorr(1)                    Khoros                     dacorr(1)

PROGRAM
     dacorr - Autocorrelation sequence of 1-D signal(s)

SYNTAX
     dacorr

     -i             input data file (xviff file)

     -o             resulting output file (xviff file)

     [-s]           number of points for autocorrelation sequence

     [-j]           define arithmetic on data

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

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

     [-V]           Gives the version for dacorr

     [-U]           Gives the usage for dacorr

     [-P]           Prompts for command line options

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

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

DESCRIPTION
     1D Autocorrelation Estimate. Generates the biased, unbiased
     or FFT based autocorrelation estimate of a data sequence.
     It can operate on Real and Complex data. If complex data,
     the user has the option of using complex arithmetic (vector)
     or real arithmetic (scalar = treat the real number and ima-
     ginary number independently).  NOTE: complex data is
     expected to be in rectangular (not polar) form.
           The autocorrelation function is a symmetric function,
           thus, only one side of the sequence is generated.

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

     Input/Output Files
     The input file must be of type VFF_TYP_FLOAT or
     VFF_TYP_COMPLEX.  The output file returned will be of size
     specified by the user.  If the data is of type
     VFF_TYP_COMPLEX and complex aithmetic is selected then the
     output file will be of type VFF_TYP_FLOAT.
     *********************************************************************

     The autocorrelation default option is the -g (biased esti-
     mate = 0) option.  When this option is selected, dacorr cal-
     culates the biased autocorrelation 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
     -i     type: infile
            desc: input data file (xviff file)

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

OPTIONAL ARGUMENTS
     -s     type: integer
            desc: number of points for autocorrelation 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 autocorrelation file to be created
            allowed values:
            0 (choose biased autocorrelation estimate),
            1 (choose unbiased autocorrelation estimate),
            or 2 (choose FFT based autocorrelation estimate)

EXAMPLES
     dacorr -i input_file -o biased_file  -s 200
     Will return a file containing 200 points of a biased auto-
     correlation estimate of the input_file.  The data processing
     direction is in the vector direction.

     dacorr -i input_file -o unbiased_file -s 512 -g 1 -j 1 -d 1
     Will return a file containing 512 points of an unbiased
     autocorrelation estimate of the input_file.  The data pro-
     cessing direction is in the band direction.

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

RESTRICTIONS
     works only on VFF_TYP_COMPLEX and VFF_TYP_FLOAT.

     dacorr does not work on explicit location data and will
     return an error when such a data file is encountered.

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

Khoros                    Release: 1.0                          1

