Benefiting from the rapid development of convolutional neural networks, the performance of car license plate detection and recognition has been largely improved. Nonetheless, most existing methods solve detection and recognition problems separately, and focus on specific scenarios, which hinders the deployment for real-world applications. To overcome these challenges, we present an efficient and accurate framework to solve the license plate detection and recognition tasks simultaneously. It is a lightweight and unified deep neural network, that can be optimized end-to-end and work in real-time. Specifically, for unconstrained scenarios, an anchor-free method is adopted to efficiently detect the bounding box and four corners of a license plate, which are used to extract and rectify the target region features. Then, a novel convolutional neural network branch is designed to further extract features of characters without segmentation. Finally, the recognition task is treated as sequence labeling problems, which are solved by Connectionist Temporal Classification (CTC) directly. Several public datasets including images collected from different scenarios under various conditions are chosen for evaluation. Experimental results indicate that the proposed method significantly outperforms the previous state-of-the-art methods in both speed and precision.
翻译:通过快速发展进化神经网络,汽车牌照的探测和识别工作得到了很大改进,但是,大多数现有方法都分别解决探测和识别问题,并侧重于阻碍实际应用部署的具体情景。为了克服这些挑战,我们提出了一个高效和准确的框架,以同时解决牌照的探测和识别任务。这是一个轻巧和统一的深层神经网络,可以优化终端到终端,实时工作。具体来说,对于未受控制的情形,采用了无锚方法,以有效检测牌照的捆绑盒和四角,用于提取和纠正目标区域特征。然后,一个新的进化神经网络分支旨在进一步提取不分割的字符特征。最后,识别任务被视为序列标签问题,由连接体温度分类直接解决。选择了几个公共数据集,包括在不同条件下收集的不同情景的图像。实验结果表明,拟议方法在速度和精确度上明显优于先前的状态方法。