ANPR is used for Detecting crime through the use of intelligence monitoring.
. Identifying stolen vehicles.
. Detecting vehicle document crime
. Electronic toll collection etc.
Description of Automatic Number Plate Recognition
There are six primary algorithms that the software requires for identifying a licence plate:
1.Plate localisation - responsible for finding and isolating the plate on the picture
2.Plate orientation and sizing - compensates for the skew of the plate and adjusts the dimensions to the required size
3.Normalisation - adjusts the brightness and contrast of the image
4.Character segmentation - finds the individual characters on the plates
5.5.Optical character recognition6.Syntactical/Geometrical analysis - check characters and positions against country specific rules
a. Poor image resolution, usually because the plate is too far away but sometimes resulting from the use of a low-quality camera.
b. Blurry images, particularly motion blur and most likely on mobile units
c. Poor lighting and low contrast due to overexposure, reflection or shadows
d. An object obscuring the plate, quite often a tow bar, or dirt on the plate
e. A different font, popular for vanity plates
f. Circumvention techniques