Car License Plate Recognition System

On the background of apartment's car auto-management system, this paper researched the technology of license plate recognition so as to improve the auto-management level. In this way we can save human resource and the system can be more safely and efficient. The license plate recognition system is composed of six parts:1. Video capture module: the CCD camera shots the dynamic or still picture of the car which goes through the entrance of the community, then the picture is collected by the image collection board and the image data is saved in the computer.2. License plate location module: this part is to find the license plate in the captured car image, so as to locate the license plate's position.3. Character segmentation module: this part is to segment the characters in the license plate so the characters will appear in the form of single characters.4. Character recognition module: this job is to identify the segmented characters so as to give the license number of the vehicle.5. Data-base process module: a data-base is build which saves amounts of car numbers and related car information. The car number has to be judged by the data-base, if the information matches, the system will give the "let go" message. The data-base can also give services like data adding, checking and editing.6. License number display module: the recognized license number will be send to this module in the end and the recognition result displayed.The hardware components of this system mainly includes computer, CCD, video image capture board, vehicle detection equipment, SCM and LED. The image capture module, license recognition module, data-base and communication part between computer and SCM are developed under VC++ 6.0 environment using C++ language; SCM program is developed under Keil 51 environment using C language; LED display part is completed by the SCM of C8051F020. the system is checked by using more than 200 pictures captured by camera and the result shows that the vehicle auto-recognition system is with high recognition rate under the condition that the illumination is suitable and the incline angle is no more than 8°.