Autonomous wide-angle license plate recognition

#The present invention relates generally to license plate recognition.

#Traffic police, highway patrol and other mobile security personnel have a need to accurately and efficiently identify potential law enforcement problems with respect to nearby motor vehicles. One well-recognized strategy is to “run” license plate numbers of such vehicles against a database.

#It is a well known practice for an officer in a patrol car to visually read a license plate of a target vehicle, and then call in the number to a support center. It is also known for an officer to utilize an on-board digital video camera to capture an image of the vehicle license plate of a parked vehicle, and even to use an on-board computer to analyze the image to determine the license plate number. In both cases, however, conscious effort is required on the part of the officer, which diverts attention from driving or other activities. In some cases the diversion of attention can be dangerous, and can even contribute to an otherwise preventable car accident.

#FIG. 1 is a side perspective view of a moving surveillance vehicle carrying a surveillance system according to the inventive subject matter, with neighboring vehicles in various lanes.

#FIG. 2 is a schematic representation of the surveillance system of FIG. 1.

#FIG. 1 generally depicts a surveillance vehicle 10 equipped with a surveillance system 20 (see FIG. 2) that is driving along a roadway 30 in lane 32. Another vehicle 40 is traveling ahead of surveillance vehicle 10 in lane 22, while vehicles 42, 44 are traveling in the same direction as surveillance vehicle 10 in lane 34. Vehicles 46 and 48 are traveling in the oncoming direction in lane 36, across low median 35. Surveillance system 20 generally comprises first and second digital video cameras 22A, 22B, a processor 24 (see FIG. 2), and a signal generator 28 (see FIG. 2).

#The surveillance vehicle 10 will often be a patrol car 10, but can be any road or off-road vehicle, including jeeps, trucks, ambulances, buses, recreational vehicles, fire engines, and so forth. The neighboring vehicles 40, 42, 44, 46 and 48 can likewise be any combination of any types of vehicles, and will obviously be dispersed around the patrol car 10 in a manner that varies infinitely over time. Most of the neighboring vehicles 40, 42, 44, 46 and 48 will have rear license plates, and some can have front license plates. In this drawing, the relevant license plates for vehicles 40, 42, 44, 46 and 48 are 40A, 42A, 44A, 46A, and 48A, respectively.

#Cameras 22A, 22B are mounted at the front and rear portions of surveillance vehicle 10. Mounting can be on the bumpers or anywhere else, and can even be located in other positions such as in the siren tower on top of the surveillance vehicle 10 or inside the cab behind the windshield. One or both of cameras 22A, 22B can be mounted in the center line of the surveillance vehicle 10, or off-center in any suitable manner. There must of course be at least one camera, which could provide front, rear, side or combination coverage. Second, third, and other cameras are optional. A person skilled in the art should recognize that more than two cameras could be mounted on surveillance vehicle 10 in suitable locations (e.g., front, rear, side or top of vehicle) to allow up to 360° license plate scan coverage.