KEYWORD
      PolygonFile BorderSize PointDistance MinimumPoints OuterObjects
      ExcludeEdgeObject

DESCRIPTION 2DObjectFinder
      2D Object Finder works with a data set that has been
      preprocessed so that features are represented with pixels
      containing ones and non-features are zero.  Threshold
      and FindBorder are two applications that may be used to
      do the preprocessing.  The object finder creates a
      polygon to surround each feature in a 2D section. If
      the input data set is a window, the polygon outlines
      will be shown, and the polygons will be available for
      other polygon manipulation programs.  The polygons may
      also be saved to a text file for later use.

      The controls for selecting the input file and region to
      process are shared with many other Priism applications
      and are described in Region.hlp.

      2DObjFinder accepts the command-line arguments described
      in Region.hlp.  In addition, it has the following
      options:

      -border=n
          Sets the number of pixels, n, along each edge that
          2DObjFinder excludes from segmentation.  n must be
          a positive integer.  By default, 2DObjFinder excludes
          a one pixel wide border around the edge of the image.

      -exclude_edge
          If specified, 2DObjFinder filters out any polygons
          that have a vertex within n+1 pixels of the sides
          of the image where n s the border size set with
          -border.

      -minpts=m
          Causes 2DObjFinder to filter out any polygons with
          less than m vertices.  The filtering takes place
          before 2DObjFinder resamples the polygons to match
          the vertex spacing set with -spacing.  By default,
          2DObjFinder filters out polygons with less than
          three vertices.

      -poly=name
          Causes 2DObjFinder to generate a file named name
          to store the polygon results.  If you do not use
          this option, 2DObjFinder does not save the polygons.

      -outer_only
          Causes 2DObjFinder to only generate the polygons
          that mark the outer boundaries of the objects
          and not the polygons that mark the edges of
          holes in the objects.

      -spacing=s
          Sets the distance between adjacent polygon vertices
          to be s pixels.  By default, 2DObjFinder will
          generate polygon vertices spaced four pixels apart.

      The following example segments the contents of window 2
      and saves the outer boundary polygons in /var/tmp/2.pol:

          2DObjFinder 2 -poly=/var/tmp/2.pol -outer_only

PolygonFile
      If you want 2DObjFinder to save the polygons to a file,
      enter the file name in the field next to the "Output
      .Pol File" button or press the "Output .Pol File" button
      to bring up a file browser to select the output file.

      If the input file is an image window and you did not
      specify a polygon output file, you can use EditPolygon
      to save the polygons to a file without repeating the
      segmentation:  run EditPolygon, enter the image window
      number that 2DObjFinder is using as its input in
      EditPolygon's "Image Window" field, and then press
      EditPolygon's "Save .POL File" button.

BorderSize
      Points within a given distance, shown in the "border size"
      field, of an image edge are not included in features, i.e.
      it is as if they were set to zero in the input data set.

PointDistance
      The "dist between pts" field determines how the polygons
      are compressed after they are generated.  The compression
      is performed on polygons with ten or more vertices.  A
      minimum side length, s, is chosen which is either the
      distance, d, show in the "dist between pts" field or,
      if the number of vertices divided by d is less than
      ten,  d - j where j is the smallest integer such that
      the number of vertices divided by d - j is greater than
      or equal to ten.  Starting from one of the vertices,
      the other vertices are considered in order and those that
      are less than the minimum side length from the previous
      vertex are eliminated.

      The compression is performed after the criteria for the
      minimum number of vertices per polygon has been applied.

MinimumPoints
      After polygons are generated, those with less than the
      number of vertices shown in the "min pts for one obj"
      field are eliminated.

OuterObjects
      If the "outer objs only" toggle is on, polygons will
      not be generated to mark holes in a feature.

ExcludeEdgeObject
      If the "exclude edge objs" toggle is on, polygons with
      a vertex within one plus the border size pixels of the
      image edge will not be generated.