Surface defects affect the quality and safety of oil seals. It is a challenge to detect such defects in a vision system because of the unequal reflection property of oil seal surfaces and low contrast between the defect and the background. This article proposes a visual detection method (VDM) for oil seal surface defects and outlines two key issues of VDMs. First, we present a superpixel segmentation algorithm based on the significant gray level variation in the radial direction of an oil seal surface image. This image is then divided into several ring belts. Subsequently, considering the reflection inequality and low contrast, we propose a new circumferential background difference algorithm based on the small variation along the circumferential direction of the image. This algorithm eliminates the influence of the reflection inequality and improves the contrast distinction between the defects and the background. The experimental results verify the effectiveness of the proposed method with a recall and precision as high as 95.2% and 86.8%, respectively.

中文翻译：

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基于超像素分割和圆周差异的油封表面缺陷检测

表面缺陷影响油封的质量和安全。由于油封表面的不均匀反射特性以及缺陷与背景之间的低对比度，在视觉系统中检测此类缺陷是一项挑战。本文提出了一种油封表面缺陷的视觉检测方法 (VDM)，并概述了 VDM 的两个关键问题。首先，我们提出了一种基于油封表面图像径向灰度显着变化的超像素分割算法。这个图像然后被分成几个环带。随后，考虑到反射不均和低对比度，我们提出了一种新的基于图像沿圆周方向变化小的圆周背景差分算法。该算法消除了反射不等式的影响，提高了缺陷与背景之间的对比度区分。实验结果验证了所提出方法的有效性，召回率和准确率分别高达 95.2% 和 86.8%。