LED芯片电极定位算法研究  

Research on Electrode Positioning Algorithm of LED Chip

作　　者：李浩霖 贺云波[1] LI Haolin;HE Yunbo(State Key Laboratory of Precision Electronic Manufacturing Technology and Equipment,Guangdong University of Technology,Guangzhou 511400,China)

机构地区：[1]广东工业大学精密电子制造技术与装备国家重点实验室,广州511400

出　　处：《组合机床与自动化加工技术》2023年第11期38-41,46,共5页Modular Machine Tool & Automatic Manufacturing Technique

基　　金：国家自然科学基金项目(61973093)。

摘　　要：针对先进封装领域中LED芯片电极定位问题,提出一种亚像素级别的电极定位方法。根据LED芯片实际的形状信息,利用霍夫变换检测图中的类圆区域,为了避免霍夫变换人工调参带来的不确定性和麻烦,对类圆区域提取HOG特征,引入支持向量机(SVM)模型对HOG特征进行分类筛选,得到目标电极区域。用Canny算子对二值化后的目标ROI区域提取像素级边缘;然后通过Zernike正交矩计算像素级边缘点的边缘参数,得到亚像素边缘点集;最后通过最小二乘法拟合亚像素边缘点得到电极区域特征圆,定位电极的中心位置。实验表明,本算法拟合直径与电极实际直径最大相差3.23μm,拟合中心达到亚像素级别精度,算法平均运行时间9.34 ms,符合先进封装设备高速高精度的要求。Aiming at the electrode positioning of LED chips in the field of advanced packaging,a sub-pixel level electrode positioning method is proposed.According to the actual shape information of the LED chip,the circle like region in the image is detected by using the Hough transform.In order to avoid the uncertainty and trouble caused by the manual parameter adjustment of the Hough transform,the HOG features are extracted from the circle like region,and the support vector machine(SVM)model is introduced to classify and screen the HOG features to obtain the target electrode region.The Canny operator is used to extract the pixel-level edge of the binary target ROI region,and then the edge parameters of the pixel-level edge points are calculated by Zernike orthogonal moments to obtain the sub-pixel edge point set.Finally,the sub-pixel edge points are fitted by the least square method to obtain the characteristic circle of the electrode area and locate the center of the electrode.The experiment shows that the maximum difference between the fitting diameter of the algorithm and the actual diameter of the electrode is 3.23μm,the fitting center reaches sub-pixel level accuracy,and the average running time of the algorithm is 9.34 ms,which meets the requirements of high-speed and high-precision advanced packaging equipment.

关 键 词：亚像素级 LED芯片 ZERNIKE矩 SVM 

分 类 号：TH165[机械工程—机械制造及自动化] TG659[金属学及工艺—金属切削加工及机床]