Licence Plate Recognition for Roadblocks and Police Vehicles

The application may be used equally well at static roadblocks and mounted in a police vehicle to read number plates of passing cars or number plates of cars stopped by the police. In either case, it provides a quick source of reference as to whether the vehicle is wanted or not and can eliminate uncertainty as to the situation before the police officers exit their vehicle.

The application uses a mobile computer with a GeoVision card installed and connected to a suitable camera. Every one hundredth of a second, the program checks to determine whether a new number plate is in view. If it is, then Licence Plate Recognition (LPR) is done and the resulting vehicle registration number is compared with a list of wanted vehicles which is supplied by the traffic authorities. This is a Microsoft Access database and a standard Access import is done to load the list of wanted registration numbers.

When the registration number is found, then a red light appears and the computer will beep until the registration plate is no longer visible (See the illustration below). A list of all vehicles detected as being in the list is maintained on the right-hand side.

If the vehicle registration is not found, then a green light indicates that the vehicle is not on the wanted list and may be allowed to proceed.

Should the traffic department require, the program could easily be modified to show the actual offences for which the vehicle is wanted.