光学镜片外观瑕疵视觉检测方法

Visual inspection method of detecting flaws on optical glasses surface

  • 摘要: 介绍了一种基于计算机视觉检测光学镜片外观瑕疵的方法。该方法主要针对麻点、划痕、毛刺和破边等瑕疵,并根据瑕疵在侧面光源作用下发生漫反射,产生亮光斑或亮光带的原理,开发了基于反射检测法的瑕疵检测装置,检测装置的工作节拍不超过5 s/片。创新使用了黑体作为暗背景,提高了瑕疵的对比度。视觉检测中利用了总面积检测法来检测镜片表面的麻点和划痕,利用边缘毛刺检测法来检测镜片边缘的毛刺和破边。在试验中检测了53块直径10 mm的镜片,准确率达到100%。最后给出了基于31万像素CCD的检测结果,其中OK镜片总瑕疵量≤100 pixel,最高灰度值≤80,麻点和划痕镜片的总瑕疵量介于200 pixel~600 pixel之间,最高灰度值≤210,毛刺/破边镜片总瑕疵量≤100 pixel,最高灰度值介于200~255之间,可见麻点镜片和划痕镜片的总瑕疵量明显比毛刺/破边镜片和OK镜片高。

     

    Abstract: A computer visual inspection method for detecting flaws on optical glasses surface was introduced. This method mainly aimed at detecting flaws such as pockmark, scratch, burr, edge damage and so on. According to the principle that bright spots and bright bands generated by the diffuse reflection of flaws under the action of side light, the flaws detection device based on reflection detection method was developed, and the work cycle of the device was less than 5 s per piece. The blackbody was creatively used to form the dark background and enhance the contrast. In the visual inspection, the total area detection method was used to detect the pockmark and scratch of glasses surface, and the edge burr detection method was used to detect the burr and edge damage of glasses edge. In the experiment, 53 pieces of 10mm diameter optical glasses were tested and the accuracy reached 100%. In the end, the detection result based on the 310 000 pixel CCD was given. According to the result, the total number of flaws on OK glasses is ≤100 (pixel), and the maximum gray value is ≤80. The total number of flaws on pockmark and scratch glasses is between 200 and 600 (pixel), and the maximum gray value is ≤210. The total number of flaws on burr/edge damage glasses is ≤100 (pixel), and the maximum gray value is between 200~255. Thus it can be seen that, the total number of flaws on pockmark and scratch glasses is obviously higher than that of flaws on burr/edge damage and OK glasses.

     

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