基于径向对称变换的速度标识牌检测方法

Speed limit sign detection based on radial symmetry transform

为解决已有速度标识牌检测方法准确率低,且没有考虑夜间情况下标识牌检测等问题,提出一种基于径向对称变换的速度标识牌检测方法。利用点与点的对偶性将圆周映射为中心的聚集点,突出图像中的圆对称区域,实现标识牌的粗定位;根据标识牌内部的数字特征排除伪目标。实验结果表明,该算法的白天平均检测率为98.54%,夜晚为95.50%,与其它标识牌检测算法相比,具有鲁棒性好、检测率高的优点。

Aiming at the problems of the low detection accuracy and little consideration put into the sign detection at night in the existing speed limit sign detection method, a method based on the radial symmetry transform for the speed limit sign detection was proposed. Firstly, the radial symmetry transform was used, points in a circle therefore were projected to its center and regions with the circular symmetry were highlighted. Thus, speed limit signs were coarsely positioned. Then, according to the characters of digits in speed limit signs, false regions were excluded. The experimental results show that the detection rate is 98.54% in daytime and 95. 50% in nighttime. Compared with other detection methods, the proposed algorithm is robust and provides a high detection performance.