Purpose

The purpose of this paper is to propose a defect detection method of silicone caps positional deviation on flexible printed circuit board (FPCB) of keyboard based on automatic optical inspection.

Design/methodology/approach

First, the center of silicone caps of target keyboard FPCB image was extracted as feature points for generating the feature image which is used for registration rigidly with the reference feature image generated from the CAD drawings. Then, a flexible image registration method based on the surrounding-control-center B-splines (SCCB) strategy was proposed, which could correct the flexible deformation of the image generated by FPCB substrate while keeping the pasting deviation information about silicone caps unchanged. Finally, on this basis, a nearest neighbor strategy was proposed to detect the positional deviation of silicone caps.

Findings

Experimental results show that the proposed method can effectively detect the positional deviation defect of silicone caps. The G-mean value of the proposed method is 0.941746, which is 0.3 higher compared to that of similar research.

Originality/value

This paper presents a method to detect positional deviation defect of silicone caps on keyboard FPCB. Different from the classic B-spline image registration method, the proposed SCCB method used the neighborhood information of the pixel to be registered selectively to calculate the displacement vector needed for its registration, which overcame the problem that the silicone cap pasting deviation information disappears with the correction of the flexible deformation of the image.

中文翻译：

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FPCB上硅胶帽的位置偏差检测

目的

本文的目的是提出一种基于自动光学检查的键盘柔性印刷电路板（FPCB）上硅胶帽位置偏差的缺陷检测方法。

设计/方法/方法

首先，提取目标键盘FPCB图像的硅胶帽的中心作为特征点，以生成用于与从CAD图纸生成的参考特征图像进行严格配准的特征图像。然后，提出了一种基于环境控制中心B样条（SCCB）策略的柔性图像配准方法，该方法可以校正FPCB基板产生的图像的柔性变形，同时保持关于硅胶帽的粘贴偏差信息不变。最后，在此基础上，提出了一种最近邻策略来检测硅胶帽的位置偏差。

发现

实验结果表明，该方法可以有效地检测出硅胶帽的位置偏差缺陷。该方法的G均值是0.941746，比类似研究的G均值高0.3。

创意/价值

本文提出了一种检测键盘FPCB上硅胶帽位置偏差缺陷的方法。与经典的B样条图像配准方法不同，建议的SCCB方法使用要配准的像素的邻域信息来选择性地计算其配准所需的位移矢量，从而克服了硅胶帽粘贴偏差信息随配角消失的问题。校正图像的柔性变形。