Developing an Algorithm for Sequential Sorting of Discrete and Connected Characters Using Image Processing of Multi-Line License Plates

Abstract

Automatic license plate recognition (ALPR) is a widely used system in developed countries to track and classify vehicles. Contrariwise, least developed countries such as Bangladesh are having issues like rotated, slightly faded license plates. Additionally, there are multi-line license plates where usually two rows are used to interpret vehicle numbers that create complexity during character extractions. These also inflate problems for the sequential sorting of the characters after extraction, let alone the rotated one. Thus, no well-established ALPR system is discoverable for those countries. Character recognition techniques might be available for some popular languages; still, they are not becoming effective due to the lack of pre-processing of the images. Therefore an effort has been made to process images of the rotated multi-line license plates to retrieve their original orientations and then extract and order all the characters sequentially accordingly. This algorithm is expected to help develop the ALPR system to distinguish individual characters even from the inferior quality license plates. Consequently, any standard recognition technique might be applied to unique character images obtained from this algorithm to recognize characters developed for any particular language accordingly.

Keywords

• ALPR
• Sequential sorting
• Multi-line license plate
• Image processing
• RGB Image