[1] [1] Varan S, Singh S, Sanjeev Kunte R, et al. A road traffic signal recognition system based on template matching employing tree classifier[C]//Proceedings of the International Conference on Computational Intelligence and Multimedia Applications, 2007: 360-365.

[2] [2] Nguwi Y Y, Cho S Y. Emergent self-organizing feature map for recognizing road sign images[J]. Neural Computing & Applications, 2010, 19(4): 601-615.

[3] [3] Garcia-Lamont F, Cervantes J, Lopez A, et al. Segmentation of images by color features: A survey[J]. Neurocomputing, 2018, 292: 1-27.

[4] [4] Hmida R, Ben Abdelali A, Mtibaa A. Hardware implementation and validation of a traffic road sign detection and identification system[J]. J Real-Time Image Process, 2018, 15(1): 13-30.

[5] [5] Garcia-Garrido M A, Sotelo M A, Martin-Gorostiza E. Fast road sign detection using hough transform for assisted driving of road vehicles[C]//Proceedings of the EUROCAST Computer Aided Systems Theory, 2005: 543-548.

[6] [6] Barnes N, Loy G, Shaw D, et al. Regular polygon detection[C]//Proceedings of the Tenth IEEE International Conference on Computer Vision, 2005: 778-785.

[7] [7] Aoyagi Y, Asakura T. A study on traffic sign recognition in scene image using genetic algorithms and neural networks[C]//Proceedings of the IEEE IECON 22nd International Conference on Industrial Electronics, Control, and Instrumentation, 1996: 1838-1843.

[8] [8] Escalera A d l, Armingol J M, Mata M. Traffic sign recognition and analysis for intelligent vehicles[J]. Image and Vision Computing, 2003, 21(3): 247-258.

[9] [9] Ruta A, Li Y M, Liu X H. Real-time traffic sign recognition from video by class-specific discriminative features[J]. Pattern Recognition, 2010, 43(1): 416-430.