
dsubsamp(1)                  Khoros                   dsubsamp(1)

PROGRAM
     dsubsamp - Subsamples 1-D vector(s).

SYNTAX
     dsubsamp

     -i             input image

     -o             resulting output image

     [-s]           Subsample skip value (0 = no skipping)

     [-x]           Point to begin subsampling

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

     [-V]           Gives the version for dsubsamp

     [-U]           Gives the usage for dsubsamp

     [-P]           Prompts for command line options

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

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

DESCRIPTION
     dsubsamp subsamples 1-dimensional vector(s) from the input
     data.  The position where the first sample is taken can be
     specified by the start parameter (-x).  For example, x = 0
     will start subsampling with the first point in each vector.
     The number of points skipped between each sample is speci-
     fied by the skip parameter (-s).  A skip value of 0 will
     cause no skipping to occur.

     Input and Output Files
                    The input file must be of data storage type
                    VFF_TYP_FLOAT or VFF_TYP_COMPLEX, be of
                    dimension = 0, and have implicit location
                    type.  The output file will contain the same
                    number of vectors and be of the same data
                    storage type as is in the input file.  The
                    vector dimension of the output file will be
                    the determined by the skip value.

     Skip Value     The skip parameter (-s) is an integer which
                    describes how many points should be skipped
                    between samples.  For example, a skip value
                    of 2 would result in the following points
                    being sampled from the input sequence:  0, 3,
                    6, 9 ... .

     First Sample Point
                    The first subsample point (-x) specifies a
                    constant offset into the input data vector(s)
                    where the first sample point is taken.

     Data Processing Direction
                    Data can be processed with either band or
                    vector orientation.  If vector processing is
                    chosen, the data stored in multiband format
                    will be 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.  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 process direction to
                    band (d = 1).

REQUIRED ARGUMENTS
     -i     type: infile
            desc: input image

     -o     type: outfile
            desc: resulting output image

OPTIONAL ARGUMENTS
     -s     type: integer
            desc: Subsample skip value (0 = no skipping)
            default: 0
            bounds: value >= 0

     -x     type: integer
            desc: Point to begin subsampling
            default: 0
            bounds: value >= 0

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

EXAMPLES
     dsubsamp -i in_file -o out_file -x 3 -s 2

     Out_file will contain the sampled set of vectors from
     in_file The first point in out_file will be point 3 (fourth
     point) from in_file, and each subsequent point will be 2
     points away from the previous point.  For example, in this
     out_file sequence, points 0,1,2 ... will contain the values
     indexed by 3, 6, 9, ... in in_file.

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

RESTRICTIONS
     Dsubsamp works only on VFF_TYP_COMPLEX and VFF_TYP_FLOAT.

     Dsubsamp 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.

Khoros                    Release: 1.0                          1

