License plate tilt correction : a review

Abstract EN

Tilt correction is an essential step in the license plate recognition system(LPR).

The main goal of this article is to provide a review of the variousmethods that are presented in the literature and used to correct differenttypes of tilt that appear in the digital image of the license plates (LP).

Thistheoretical survey will enable the researchers to have an overview of theavailable implemented tilt detection and correction algorithms.

That'show this review will simplify for the researchers the choice to determinewhich of the available rotation correction and detection algorithms toimplement while designing their LPR system.

This review also simplifiesthe decision for the researchers to choose whether to combine two or moreof the existing algorithms or simply create a new efficient one.

This reviewdoesn't recite the described models in the literature in a hard-narrativetale, but instead, it clarifies how the tilt correction stage is divided basedon its initial steps.

The steps include: locating the plate corners, findingthe tilting angle of the plate, then, correcting its horizontal, vertical, andsheared inclination.

For the tilt correction stage, this review clarifies howstate-of-the-art literature handled each step individually.

As a result, it hasbeen noticed that line fitting, Hough transform, and Randon transform arethe most used methods to correct the tilt of a LP