A
system and methods are disclosed for enhancing
license plate recognition (LPR) and vehicle
feature recognition processes in automatic vehicle
access control, parking management, automatic
toll collection and security applications. The
system uses
optical character recognition (OCR) to read
license plates, while utilizing image
feature recognition to verify plate reading results, and correct any OCR read errors, thereby increasing
system accuracy. The system automatically controls the actuation of one or a plurality of gates / barriers to allow entry and exit of authorized vehicles to or from a premises, a
parking lot or a
toll station. In the event of failure of the OCR
algorithm to identify a
license plate of an authorized vehicle at an entry or
exit point, the system allows a
human operator or the driver / passenger of the said authorized vehicle to override its decision, and allow the vehicle to pass by opening the gate or barrier through external means including
card reader, bio-metric
scanner, key fob,
cell-phone /
smart phone,
wireless transceiver, electro-mechanical switch / button, or PC / Web based application. This overriding action of opening the gate / barrier through the said external means is used to tune the license plate and vehicle
recognition system, causing it to adapt its algorithms to perform better when it encounters the same vehicle again. Besides the above aspect, the present invention discloses fast and memory-efficient methods for image
feature matching that are well suited for real-time situations where the set of
reference image features is changing with time as new vehicles arrive. In addition to the above aspects, the present invention discloses an LPR
database update method that simplifies license plate misread corrections process in the
database, thereby improving the accuracy of subsequent
database search queries. Furthermore, the present invention discloses methods in an LPR system that account for all the passing traffic by categorizing and recording license plate / vehicle captures as read-plate records, unread-plate records, or vehicles with missing license plates. In addition to the above aspects, the present invention discloses methods for switching between normal and privacy
modes of operation and between different security levels.