NAME

Image::OpenALPR - Perl binding for Automatic License Plate Recognition library

SYNOPSIS

  use Image::OpenALPR;
  my $alpr = Image::OpenALPR->new('eu');
  $alpr->get_version; # 2.2.4
  my (@plates) = $alpr->recognise('many_plates.jpg');
  say 'Plates found: ', join ' ', map { $_->plate } @plates;

  $alpr->set_top_n(2);
  my $data = read_file 'one_plate.gif';
  my $a_plate  = $alpr->recognise(\$data);
  my @cnd = @{$a_plate->candidates};
  say $cnd[0]->plate, ' ', $cnd[0]->confidence;
  say $cnd[1]->plate, ' ', $cnd[1]->confidence;

DESCRIPTION

OpenALPR is an automatic license plate recognition library that extracts license plate numbers from images.

The following methods are available:

Image::OpenALPR->new($country, $config, $runtime_data)

Takes one mandatory argument (the country rules to use, such as eu or us) and two optional arguments: a path to the configuration file, and a path to the runtime_data directory.

Returns a new Image::OpenALPR instance. If initialisation fails (for example, if the chosen country is not available) an exception is thrown.

$alpr->recognise($file)

$alpr->recognise(\$data)

Takes a path to an image file or a reference to the contents of an image file and tries to find license plates in the image. In list context, it returns a list of Image::OpenALPR::PlateResult objects, one for each plate found. In scalar context it returns only one such object (the first plate found), or undef if no plates were found.

$alpr->get_version

$alpr->getVersion

Returns the version of the OpenALPR library.

$alpr->set_country($country)

$alpr->setCountry($country)

Changes the country rules in use.

$alpr->set_prewarp($prewarp)

$alpr->setPrewarp($prewarp)

Sets the camera calibration values, as obtained from the openalpr-utils-calibrate utility. Can also be set in the configuration file.

$alpr->set_default_region($region)

$alpr->setDefaultRegion($region)

Sets the expected region for pattern matching. This improves accuracy. The matches_template flag is set on plates that match this pattern.

$alpr->set_top_n($n)

$alpr->setTopN($n)

Sets the maximum number of candidates to return for one plate. Default is 10.

SEE ALSO

http://www.openalpr.com, https://github.com/openalpr/openalpr

AUTHOR

Marius Gavrilescu, <marius@ieval.ro>

COPYRIGHT AND LICENSE

Copyright (C) 2016 by Marius Gavrilescu

This file is part of Image-OpenALPR.

Image-OpenALPR is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

Image-OpenALPR is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License along with Image-OpenALPR. If not, see <http://www.gnu.org/licenses/>