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 estimate),
    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 complex 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 estimate = 0) option. When this option is selected, dxcorr calculates 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 location. 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 processing 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.