dextract(1)

PROGRAM
dextract - Extracts 1-D Subsignal(s)

SYNTAX

dextract

-i  input image

-o  resulting output image

[-x]
    Starting point for data subset

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

[-e]
    Extract rest of file
    -OR-

[-l]
    Specify length

[-V]
    Gives the version for dextract

[-U]
    Gives the usage for dextract

[-P]
    Prompts for command line options

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

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

DESCRIPTION
dextract extracts 1-dimensional subsignals from the input data file.

Dextract will extract N subsignal vectors from an input file of N signal vectors. All vectors will be extracted starting from the same initial position (-x option), and all will be of the same length (-e or -l options).

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

Starting Point
    The starting point (-x) option specifies the offset into the data set where the first point of the output sequence is. The default value is 0 (the first point of the input series).

Length of output sequence
    Two mutually exclusive options are available for specifying the length of the output sequence, -e (logical) and -l (int).

    The default option is the -e (extract to end of sequence) option. When this option is selected, dextract calculates the number of points to the right of the first point specified (-x), and the output file is assigned this calculated length.

    The other option available for specifying output file length is is the -l (length) option. The -l option allows the user to specify the length of the output sequence. If the specified value is greater than the input file length minus the index to first point is specified, dextract returns an error and exits. The default -l value is 1.

Process direction
    Data can be processed with either band or vector orientation (-d option). The default data processing direction is in the band direction (d = 1). This means that each band is processed as a signal (instead of each vector being a signal). The direction of processing can be changed so that data stored in multiband format will be processed as vectors, by setting the -d option to 0. In other words, the data is processed as a set of data sequences, where each sequence corresponds to a pixel location, and the points of each sequence are defined by the bands corresponding to that pixel location.

REQUIRED ARGUMENTS

-i  type: infile
    desc: input image

-o  type: outfile
    desc: resulting output image

OPTIONAL ARGUMENTS

-x  type: integer
    desc: Starting point for data subset
    default: 0
    bounds: value >= 0

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

*** These arguments are MUTUALLY EXCLUSIVE ***
 If desired, you may provide ONE AND ONLY ONE of:

-e  desc: Extract rest of file
    default: true

-l  desc: Specify length
    default: 1
    bounds: value > 0
    ********

EXAMPLES
dextract -i input_file -o extracted_file -x 18 -l 20

Will return a file containing the subsignal(s) that are 20 points long, starting at point 18 in the original image.

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

RESTRICTIONS
Dextract works only on VFF_TYP_COMPLEX and VFF_TYP_FLOAT.

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

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