基于活动轮廓模型的外绝缘紫外放电特征提取

External insulation ultraviolet discharge feature extraction based on active contour model

光斑面积是紫外放电中的重要参量,外绝缘紫外放电研究中需提取光斑面积的图像很多,为了自动、准确提取出外绝缘紫外放电图像中的光斑面积,提出了一种基于活动轮廓模型的光斑面积提取方法。活动轮廓模型通过计算偏微分方程实现紫外放电图像中放电区域轮廓的获得,与常规基于局部图像信息获得边缘的方法不同,该方法具有全局优化能力,抗干扰能力强,无需预处理,对图像清晰度要求不高,能准确提取出紫外放电的光斑面积。实现了常规边缘检测算子、数学形态学法和本文方法用于绝缘子紫外放电光斑面积的提取,结果表明:常规边缘算子所得边缘干扰多,且边缘点离散,后续难以计算获得光斑面积。本文方法能准确提取出一个或多个光斑的面积,不存在数学形态学法需要人为确定图像二值化时最佳阈值和根据干扰光斑面积调整结构元素尺寸的问题,具有很好的自动化性能。

Light spot area is an important parameter of ultraviolet discharge. The light spot areas of many images need to be extracted in external insulation ultraviolet discharge study. In order to extract the light spot area in external insulation ul- traviolet discharge image automatically and accurately,a light spot area extraction method based on active contour model is proposed in the paper. With the active contour model,the ultraviolet discharge region contour is obtained through calculat- ing partial differential equation. The algorithm has global optimization capacity, and is different from the conventional meth- od that obtains the edge based on local image information. This method has strong capacity of resisting disturbance and low requirement for image definition ;in the meantime ,it does not require preprocessing, and can obtain the light spot area of ultraviolet discharge accurately. Conventional edge detection operator, mathematical morphology method and the proposed method were implemented to obtain the light spot areas of ultraviolet discharge images. The result indicates that the edge obtained with conventional edge detection operator contains much interference ,the obtained contour points are discrete ,and it is difficult to obtain the light spot area through subsequent calculation. The proposed method can obtain the areas of sin- gle or multiple light spots accurately. The method does not have the problems that the mathematical morphology method re- quires factitiously determining the optimal threshold for image binarization and adjusting the dimensions of the structure el- ements according to the area of interference light spot, and has good automation performance.