基于改进Hough变换的雾中绝缘子裂纹检测与研究

鉴于航拍雾中绝缘子图像出现颜色失真与裂纹检测效果不理想的问题，采用了一种改进Hough变换对雾中绝缘子定位与裂纹检测方法。针对颜色失真的弊端，通过大气光强度与暗通道之差的绝对值改进透视率计算公式，使之改善蓝天、白云等光亮区域去雾后颜色失真的情况。对于绝缘子定位与裂纹检测的障碍，提出了椭圆圆心是此椭圆内外所有点中到边缘最大长度最小的点这一特征，快速计算出圆心以此降低Hough参数维度与计算量,实现绝缘子在图像中的定位。最后采用Hough空间中峰值检测与置零法相结合，解决传统Hough变换检测直线算法耗时久与准确率低的短板。通过设定阈值减少伪裂纹与过连接的产生，快速并准确的检测出裂纹。通过仿真实验验证，文中所提的改进Hough变换相比传统Hough变换对雾中绝缘子裂纹检测速率提升了1.4倍，准确率提高了5.5%。

Detection and research of insulator cracks in fog based on improved Hough transform

In view of the problems of color distortion and unsatisfactory crack detection effect in aerial image of insulators in fog, an improved Hough transform method is adopted to locate and detect the cracks of insulators in fog. Aiming at the disadvantage of color distortion, the formula of perspective is improved by the absolute value of the difference between atmospheric light intensity and dark channel, so as to improve the color distortion of bright areas such as blue sky and white clouds after defogging. For the obstacle of insulator positioning and crack detection, the feature that the center of the ellipse is the point with the minimum maximum length to the edge of all points inside and outside the ellipse is proposed, and the center of the circle is calculated quickly to reduce the Hough parameter dimension and calculation amount, so as to realize insulator positioning in the image. Finally, the combination of peak detection and zeroing in Hough space is used to solve the problem of time-consuming and low accuracy of traditional Hough transform linear detection algorithm. By setting the threshold value, the generation of false cracks and over connections can be reduced, and the cracks can be detected quickly and accurately. The simulation results show that the improved Hough transform proposed in this paper improves the detection rate of insulator cracks in fog by 1.4 times and the accuracy rate by 5.5% compared with the traditional Hough transform.