提出一种基于端面图像对称性特征的偏振轴检测算法。该算法利用图像极坐标变换来实现图像的对称性检测,使用金字塔搜索法快速寻找最优对称轴,确定偏振轴向。所提算法利用图像的全局性特征而不依赖于应力区边缘点位置实现精确定位,对图像清晰度要求显著降低。实验结果表明,所提算法具有较高的准确性和精确性(±0.1°),其稳健性大幅增强,且算法速度提升了近1.5倍。

A polarization axis detection algorithm is proposed based on the symmetric features of end-view images, in which the polar coordinate transformation of the images is first used to realize the symmetry detection of images, the pyramid searching method is then utilized to quickly find the optimal symmetric axis, and finally the direction of the polarization axis is determined. Since the proposed algorithm can achieve an accurate positioning by utilizing the global features of images instead of the edge points in the stress region, the requirement for the sharpness of image is greatly reduced. The experimental results show that the proposed algorithm possesses high accuracy and precision (±0.1°), indicating the robustness is greatly enhanced, and simultaneously the speed of this algorithm is improved by nearly 1.5 times.