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 estimate)
       [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 imaginary 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 estimate = 0) option. When this option is selected, dacorr calculates 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 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

-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 autocorrelation 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 processing 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.