Name
Image::Find::Paths - Find paths in an image.
Synopsis
Use new to create and analyze a new image, then print to visualize the paths detected, or path to get the coordinates of points along each path in sequential order with an estimate of the thickness of the path at each point.
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.
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 $d = new(<<END);
11 111
11 1 111
1111 111 111
1 111111 1 111
111 1111 111 111
11 1111111 1 1
11 11111 1 1
1 111 1 1 1
1111111111 1 111111 1
111 1 1 1
END
is_deeply [$d->count, $d->x, $d->y, $d->numberOfPaths], [96, 80, 10, 6];
ok nws($d->print) eq nws(<<END);
0 1 2 3 4 5 6 7 8
01234567890123456789012345678901234567890123456789012345678901234567890123456789
0 E1 E
1 11 23
2 1111 3
3 1 322E S 3
4 111 2 E1 2S
5 11 221S 1
6 11 23 1 E
7 1 3 1 S 1
8 11111112 1 E1111 1
9 S S
Image: X = 80, Y = 10, Paths = 6
END
is_deeply $d->path(5),
[[79,4, 1], [78,4, 2], [78,3, 3], [78,2, 3], [78,1, 3], [77,1, 2], [77,0, 1]];This is a static method and so should be invoked as:
Image::Find::Paths::newnumberOfPaths($)
Number of paths in the image.
Parameter Description
1 $i Image Example:
is_deeply [$d->count, $d->x, $d->y, $d->numberOfPaths], [96, 80, 10, 6];path($$)
Returns an array of arrays [x, y, t] where x, y are the coordinates of each point sequentially along the specified path and t is the estimated thickness of the path at that point. Paths are numbered from 1 to numberOfPaths.
Parameter Description
1 $i Image
2 $partition Partition Example:
is_deeply $d->path(5),
[[79,4, 1], [78,4, 2], [78,3, 3], [78,2, 3], [78,1, 3], [77,1, 2], [77,0, 1]];print($)
Print the image: use S, E to show the start and end of each path, otherwise use the estimated thickness of the path at each point to mark the track of each path within each connected partition of the image.
Parameter Description
1 $i Image Example:
ok nws($d->print) eq nws(<<END);
0 1 2 3 4 5 6 7 8
01234567890123456789012345678901234567890123456789012345678901234567890123456789
0 E1 E
1 11 23
2 1111 3
3 1 322E S 3
4 111 2 E1 2S
5 11 221S 1
6 11 23 1 E
7 1 3 1 S 1
8 11111112 1 E1111 1
9 S S
Image: X = 80, Y = 10, Paths = 6
ENDAttributes
Attributes of an image
count :lvalue
Number of points in the image.
image :lvalue
Image data points.
partitions :lvalue
Number of partitions in the image.
partitionEnd :lvalue
End points for each path.
partitionStart :lvalue
Start points for each path.
partitionPath :lvalue
Path for each partition.
x :lvalue
Image dimension in x.
y :lvalue
Image dimension in y.
Private Methods
clone($)
Clone an image.
Parameter Description
1 $i Image Example:
is_deeply $d, $d->clone;clonePartition($$)
Clone a partition of an image.
Parameter Description
1 $i Image
2 $partition Partition countPixels($)
Count the pixels in an image.
Parameter Description
1 $i Image height($)
Clone an image adding height to each pixel.
Parameter Description
1 $i Image partition($)
Partition the images into disjoint sets of connected points.
Parameter Description
1 $i Image mapPartition($$$)
Locate the pixels in the image that are connected to a pixel with a specified value.
Parameter Description
1 $i Image
2 $x X coordinate of first point in partition
3 $y Y coordinate of first point in partition start($$)
Find the starting point for a path in a partition.
Parameter Description
1 $i Image
2 $partition Partition end($$)
Find the other end of a path in a partition.
Parameter Description
1 $i Image
2 $partition Partition traverseToOtherEnd($$$$)
Traverse to the other end of a partition.
Parameter Description
1 $I Image
2 $partition Partition
3 $X Start x coordinate
4 $Y Start y coordinate searchArea($$$$)
Return the pixels to search from around a given pixel.
Parameter Description
1 $i Image
2 $partition Partition
3 $x X coordinate of center of search
4 $y Y coordinate of center of search. checkAtLevelOne($$$)
Confirm that the specified pixel is at level one.
Parameter Description
1 $i Image
2 $partition Partition
3 $pixel Pixel searchAreaHighest($$$$$$)
Return the highest pixels to search from around a given pixel.
Parameter Description
1 $i Image
2 $partition Partition
3 $seen Pixels already visited
4 $depth Depth of search
5 $x X coordinate of center of search
6 $y Y coordinate of center of search. shortestPathBetweenEndPoints($$$)
Find the shortest path between the start and the end points of a partition.
Parameter Description
1 $I Image
2 $i Image height clone
3 $partition Partition widthOfPath($$)
Find the (estimated) width of the path at each point.
Parameter Description
1 $I Image
2 $partition Partition widthOfPaths($)
Find the (estimated) width of each path at each point.
Parameter Description
1 $i Image printHeader($)
Print a header for the image so we can locate pixels by their coordinates.
Parameter Description
1 $i Image Index
2 clone
4 count
6 end
7 height
8 image
10 new
12 partition
13 partitionEnd
15 partitions
17 path
18 print
19 printHeader
20 searchArea
22 shortestPathBetweenEndPoints
23 start
25 widthOfPath
26 widthOfPaths
27 x
28 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 installAuthor
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.