vextract(1)

PROGRAM
vextract - Extract a rectangular piece from an image and put it in a subimage

SYNTAX

vextract

-i  input image

-o  resulting output image

[-i1]
    input coordinate image

[-x]
    specifies upper left x coordinate of subimage

[-y]
    specifies upper left y coordinate of subimage

[-w]
    specifies the subimage width in pixels

[-h]
    specifies the subimage height in pixels

[-V]
    Gives the version for vextract

[-U]
    Gives the usage for vextract

[-P]
    Prompts for command line options

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

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

DESCRIPTION
vextract copies that area of the input image which is w pixels wide and h pixels high with the upper left corner at (x,y) into a new image, called a subimage. The subimage can then be treated just like an normal image and can be reinserted back into the original or any other image of the same data type.

If the subimage specification extends beyond the image boundary, the largest possible subimage is returned. If the subimage is larger than the original image, the routine will fail.

Vextract allows a coordinate input image to specify the region to extract rather than specifing the region by the -x, -y, -h and -w arguments. If the -i1 argument (input coordinate image) is specified then none of the specific coordinate values (-x, -y, -w -h arguments) can be specified. The coordinate input image must contain at least 2 columns and 3 rows. The following explains how the coordinate input image is used to extract a sub-region. The first 2 data points in the image are the x any y offset values. These specify the -x and -y arguments. To find the width of the subimage, the first value in the second row is subtracted from the first value of the first row. To find the height of the subimage, the second value in the third row is subtracted from the second value of the first row. Basically the coordinate image should be specifed as (but is not limited to) an image with three rows and two columns where each row specifies the (x,y) location of a point. Then the first row specifies the (x,y) location of the upper left hand corner, the second row specifies the (x,y) location of the upper right hand corner and the third point specifies the lower left hand corner.

The output image is the same data type as the input image. An image with only the color map and header data is obtained if none of the options are used.

The input image may be single or multiband, and the resulting output image will be of the same type and same number of bands.

REQUIRED ARGUMENTS

-i  type: infile
    desc: input image

-o  type: outfile
    desc: resulting output image

OPTIONAL ARGUMENTS

-i1 type: infile
    desc: input coordinate image

-x  type: integer
    desc: specifies upper left x coordinate of subimage
    default: 0
    bounds: value >= 0

-y  type: integer
    desc: specifies upper left y coordinate of subimage
    default: 0
    bounds: value >= 0

-w  type: integer
    desc: specifies the subimage width in pixels
    default: 128
    bounds: value > 0

-h  type: integer
    desc: specifies the subimage height in pixels
    default: 128
    bounds: value > 0

EXAMPLES
vextract -i ball.xv -o ball_sub.xv -x 64 -y 64 -w 128 -h 128

This extracts a subimage from ball.xv beginning at coordinates (64, 64), and the resulting output image is of dimension 128 by 128.

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

RESTRICTIONS

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