Automated license plate recognition of Philippine license plates

• Main Authors: Villanueva, Myra Josephine S., Ilao, Joel P., Cervania, Chloe Michelle K., Ku, Vincent Spencer Y., Ragos Ty, Desmond Carvey T.
• Format: text
• Published: Animo Repository 2005
• Subjects: Optical pattern recognition; Automobile license plates > Data processing; Computer Sciences
• Online Access: https://animorepository.dlsu.edu.ph/faculty_research/3211
• Institution: De La Salle University

Automated License Plate Identifier (ALDEN) is a License Plate Recognition (LPR) System developed to recognize images of Philippine license plates. ALDEN captures images of an approaching vehicle when a sufficient distance from the camera is obtained, localizes the license plate from the scene and reads its content. This system is designed to be robust against changes in illuminations, and to a limited degree, correct perspective distortions in the acquired images, while still maintaining real-time performances. This paper describes the design and implementation of the ALDEN. Pre-processing techniques are first applied to the acquired raw images to correct uneven illumination, and perspective distortion. The license plate is then extracted from the visual scene, binarized, and segmented into characters using knowledge of the size and locations of characters in a license plate area using the Philippine License Plate format. Character Identification is then performed by segmenting the characters into sixteen regions, and comparing the regions with character templates using correlation as a similarity measure. Performance tests using this technique tested on 300 character images yield an average recognition rate of 93.75 percent.