The issue of car license plate recognition is a focus direction of studying both at home and abroad at present

its success has important application values in vehicle controlling

transportation management

parking and so-so. There are many papers published in the research domain. In order to solve the primary problem of the car license plate recognition--Automatic orientation technology of the car license plates

a method of automatic detection and orientation of car license plate based on license plate's projection invariability in the condition of lesser deflection of car license is presented in terms of the imaging characteristics of the car license plate target

which can succeed in detecting and orienting the car license plate from the complicated background. Tested actually through the scene

the method obtains satisfactory localization effect. In the end of the paper

some experimental results are given out. In virtue of the successful car license plate detection and localization

it is possible for license plate number extraction and recognition.