Automatic license plate recognition (ALPR)
is the extraction of vehicle license plate information from an
image or a sequence of images. The extracted information can
be used with or without a database in many applications, such
as electronic payment systems (toll payment, parking fee
payment), and freeway and arterial monitoring systems for
traffic surveillance. The ALPR uses either a color, black and
white, or infrared camera to take images.
These plates usually contain different
colors, are written in different languages, and use different
fonts; some plates may have a single color background and
others have background images. In this paper, we present a
comprehensive review of the state-of-the-art techniques for
ALPR. We categorize different ALPR techniques according to the
features they used for each stage, and compare them in terms
of pros, cons, recognition accuracy, and processing speed.
Future forecasts of ALPR are given at the end.