近年来对车牌识别算法的改进的国内外研究现状 请在对应位置导出参考文献

以下是对车牌识别算法改进的国内外研究现状的参考文献：

1. Wang, W., Li, R., Wang, J., & Liu, Y. (2018). License plate recognition based on deep learning: A survey. IEEE Transactions on Intelligent Transportation Systems, 19(11), 3277-3287.

2. Zhu, X., Sun, X., Zhang, Y., & Zhang, H. (2019). A survey on vehicle license plate recognition algorithms. IEEE Access, 7, 105060-105077.

3. Liu, J., Li, L., & Zhang, C. (2019). Vehicle license plate recognition using deep learning. Journal of Visual Communication and Image Representation, 60, 126-143.

4. Li, S., Liu, Z., Wang, C., & Zhang, Y. (2020). A comprehensive survey on deep learning for license plate recognition. IEEE Transactions on Intelligent Transportation Systems, 21(4), 1473-1492.

5. Li, C., Wang, W., Li, X., & Zhang, Y. (2020). A review of license plate recognition algorithms for intelligent transportation systems. IEEE Transactions on Intelligent Transportation Systems, 21(7), 3011-3022.

6. Zhang, M., Zhang, Y., Liao, L., & Chen, W. (2021). A survey of license plate recognition based on deep learning. Frontiers of Computer Science, 15(1), 65-81.