/ 
Image-Find-Paths-20180503
River stage zero No dependents
/ Image::Find::Paths

Name

Image::Find::Paths - Find paths in an image.

Synopsis

Description

Find paths in an image.

The following sections describe the methods in each functional area of this module. For an alphabetic listing of all methods by name see Index.

Attributes

Attributes of an image

count :lvalue

Number of points in the image.

image :lvalue

Image data points.

partitions :lvalue

Number of partitions in the image.

partitionEnd :lvalue

End points for each path.

partitionStart :lvalue

Start points for each path.

partitionPath :lvalue

Path for each partition.

x :lvalue

Image dimension in x.

y :lvalue

Image dimension in y.

Methods

Find paths in an image

new($)

Find paths in an image represented as a string.

   Parameter  Description
1  $string    String of blanks; non blanks; new lines defining the image

Example:

my $d = new(<<END);
     11                                                                        1
      11                                                                 1     1
       1111                            111                                     1
          1                           111111             1                     1
        111                            1111             111                    1
       11  1111111                      1                1
      11    11111                       1                                      1
      1      111                        1                 1                    1
     1111111111                         1             111111                   1
              111                       1                               1      1
END

ok $d->x     == 80;

ok $d->y     == 10;

ok nws($d->print) eq nws(<<END);
     E1                                                                        E
      11                                                                       1
       1111                                                                    1
          1                             322E             S                     1
        111                             2               E1                     S
       11    2221S                      1
      11     2                          1                                      E
      1      3                          1                 S                    1
      11111112                          1             E1111                    1
                                        S                                      S
END

ok $d->numberOfPaths == 6;

is_deeply $d->path(5),

[[79, 4, 1], [79, 3, 1], [79, 2, 1], [79, 1, 1], [79, 0, 1]];

This is a static method and so should be invoked as:

Image::Find::Paths::new

numberOfPaths($)

Number of paths in the image. The partitions and paths are numbered from 1.

   Parameter  Description
1  $i         Image

Example:

ok $d->numberOfPaths == 6;

path($$)

Path for a specified partition. The partitions and paths are numbered from 1. Returns an array of arrays [x, y, t] where x, y are the coordinates of each point sequentially along the path and t is the estimated thickness of the path at that point.

   Parameter   Description
1  $i          Image
2  $partition  Partition

Example:

is_deeply $d->path(5),

[[79, 4, 1], [79, 3, 1], [79, 2, 1], [79, 1, 1], [79, 0, 1]];

print($)

Print the image: use S, E to show the start and end of each path, otherwise use the estimated thickness of the path at each point to mark the track of each path within each connected partition of the image.

   Parameter  Description
1  $i         Image

Example:

ok nws($d->print) eq nws(<<END);
     E1                                                                        E
      11                                                                       1
       1111                                                                    1
          1                             322E             S                     1
        111                             2               E1                     S
       11    2221S                      1
      11     2                          1                                      E
      1      3                          1                 S                    1
      11111112                          1             E1111                    1
                                        S                                      S
END

Private Methods

clone($)

Clone an image.

   Parameter  Description
1  $i         Image

Example:

is_deeply $d, $d->clone;

partition($)

Partition the images into disjoint sets of connected points.

   Parameter  Description
1  $i         Image

mapPartition($$$)

Locate the pixels in the image that are connected to a pixel with a specified value

   Parameter  Description
1  $i         Image
2  $x         X coordinate of first point in partition
3  $y         Y coordinate of first point in partition

traverseToOtherEnd($$$$)

Traverse to the other end of a partition.

   Parameter   Description
1  $I          Image
2  $partition  Partition
3  $x          Start x coordinate
4  $y          Start y coordinate

start($$)

Find the starting point for a path in a partition.

   Parameter   Description
1  $i          Image
2  $partition  Partition

end($$)

Find the other end of a path in a partition.

   Parameter   Description
1  $i          Image
2  $partition  Partition

searchArea($$$$)

Return the pixels to search from around a given pixel.

   Parameter   Description
1  $i          Image
2  $partition  Partition
3  $x          X coordinate of center of search
4  $y          Y coordinate of center of search.

shortestPathBetweenEndPoints($$)

Find the shortest path between the start and the end points of a partition.

   Parameter   Description
1  $I          Image
2  $partition  Partition

widthOfPath($$$)

Find the (estimated) width of the path at each point

   Parameter   Description
1  $I          Image
2  $i          Cloned copy of image
3  $partition  Partition

widthOfPaths($)

Find the (estimated) width of each path at each point

   Parameter  Description
1  $I         Image

Index

1 clone

2 count

3 end

4 image

5 mapPartition

6 new

7 numberOfPaths

8 partition

9 partitionEnd

10 partitionPath

11 partitions

12 partitionStart

13 path

14 print

15 searchArea

16 shortestPathBetweenEndPoints

17 start

18 traverseToOtherEnd

19 widthOfPath

20 widthOfPaths

21 x

22 y

Installation

This module is written in 100% Pure Perl and, thus, it is easy to read, use, modify and install.

Standard Module::Build process for building and installing modules:

perl Build.PL
./Build
./Build test
./Build install

Author

philiprbrenan@gmail.com

http://www.appaapps.com

Copyright

Copyright (c) 2016-2018 Philip R Brenan.

This module is free software. It may be used, redistributed and/or modified under the same terms as Perl itself.