Number Plate Recognition
What is Number Plate Recognition?
NPR
(Number Plate Recognition) is
an image-processing technology
used to automatically identify vehicles by their number plate captured by a
camera, allowing these details to be compared against database records. NPR
systems are used in various security and traffic application, such as
access-control, parking and so on.
For
example in an access-control system, when the vehicle arrives the gate of the
area it wants to enter into, the NPR unit will takes pictures of the vehicle and
“reads” the plate number from the picture, compares it to a predefined list and
opens the gate if there is a match.
NPR Process
The steps involved in NPR include image pre-processing which
first adjust the contrast and brightness of the image and then change it into
greyscale. Next step is called plate localization, the number plate is
recognized and isolated in this step. After isolated the plate, the size and the
shape of the plate area are adjusted in a step called resizing. And then, the
individual characters in the number plate are separated and identified through
character segmentation and optical character recognition.
The identified number is then used to
compare with the records in a database to show the related information like the
vehicle’s owner, place of registration, address and so on.
- Only support Irish number plate.
- Supported image type: support two kinds of common image type: BMP and JPG.
- Supported image size: 600 pixels X 500 pixels
- Image quality: allow the image be taken in front of the number plate around 2
meters with a tilt angle less than 3°, allow complex background and certain
amount of noises the imported image.
- High recognition rate: the correct read rate of number plates is higher than
90%.
- High efficiency: takes less than 5 seconds to output the result after import an
image.
- Easy to use: the functions are all practical with friendly interface.
Document
Developer Information
Name: Dongfan Kuang (C00131031)
E-mail: C00131031@itcarlow.ie
B.Sc. Hons. in Software Engineering
Institute of Technology, Carlow