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为测量印刷线路板(PCB)上密集直线的线宽,构建了由CCD摄像机、视频采集卡、照明装置和PC机组成的光机电一体测量系统。该系统首先用矩形框获取包含被测线宽的局部图像,并进行相应的预处理;然后,采用扫描方法获取被测线宽的两边缘点集,进而采用最小二乘拟合、奇异点去除、再次拟合的方法获取两边缘直线方程;最后,利用去奇异点后的两边缘点集和两边缘直线方程计算得到直线的线宽。仿真和真实线宽测量实验结果表明,该系统具有较高的测量效率和精度,其重复测量精度优于2μm,已被多家PCB生产厂采用。
In order to measure the line width of dense linear printed circuit board (PCB), an optical mechatronic system consisting of a CCD camera, a video capture card, a lighting device and a PC is constructed. In the system, a rectangular frame is used to get the local image containing the measured linewidth and pretreatment. Then, the two edge points of the measured linewidth are obtained by the scanning method, and then the least square fitting and singular point removal , Fitting again to obtain the two-edge linear equation; Finally, using the two-edge point set to the singular point and the two-edge linear equation to calculate the line width. The experimental results of simulation and real linewidth measurement show that the system has high measurement efficiency and accuracy, and its repeated measurement accuracy is better than 2μm, which has been adopted by many PCB factories.