基于扇形条纹调制度的光滑平面缺陷检测

Detection of mirror defects based on sector fringe reflection

在光滑表面缺陷检测过程中,调制度可以用来标记缺陷位置。为了提高缺陷检测的准确性,提出了一种基于扇形条纹的调制度检测方法,该方法对缺陷位置和方向有更高的灵敏度,适用于多种类型的缺陷检测。首先,由变形条纹解调得到调制度图,调制度的高低可判断是否存在缺陷,再基于调制度图产生新的质量图——调制度-相位梯度偏差质量图,由此可以识别出缺陷位置。8组对比实验表明,同一实验环境下,基于扇形条纹的调制度缺陷检测方法不仅能检测出单一走向的缺陷,对复合走向的缺陷检测效果也很好,能更完整地检测缺陷,同时检测缺陷的精确度达到了0.07 mm。与传统的机器视觉方法和水平/垂直/圆形条纹检测法相比,本文所提出的扇形调制度法具有更高的灵敏度和准确性。

For detecting mirror plane defects,fringe modulation is generally regarded as an effective method.To improve the accuracy of defect detection,this paper proposes a sector fringe-based modulation testing method.The proposed method is more compatible with the defect direction and suitable for many types of defects.A new quality map is used based on deformed fringe modulation and phase gradient deviation to identify the locations of defects.Eight groups of experiments are conducted and compared.Results show that the modulation and phase gradient quality map can suppress the selectivity of defect directions and the testing accuracy of defects can reach a minimum size of 0.07 mm.Compared with the traditional machine vision method and horizontal/vertical/circular fringe-based methods,the proposed sector fringe modulation method offers state-of-the-art sensitivity and higher accuracy.