基于改进Canny算子的LED晶片边缘检测  

LED wafer edge detection based on improved Canny operator

作　　者：温阳东[1] 顾倩芸[1] 陈雪峰[1] 

机构地区：[1]合肥工业大学电气与自动化工程学院,合肥230009

出　　处：《计算机应用》2013年第9期2698-2700,共3页journal of Computer Applications

摘　　要：为了提高全自动固晶机视觉系统中发光二极管(LED)晶片边缘特征的提取精度,提出了一种基于改进非极大值抑制(NMS)过程和双阈值求取方法的Canny边缘检测算子。传统的非极大值抑制过程,直接将中心像素点与梯度方向周围邻近的2个像素点进行比较,易导致边缘信息不准确。针对该问题,结合中心像素点本身及其梯度方向周围的3个像素点,沿着梯度方向进行双线性插值,从而实现改进的非极大值抑制过程;另外,通过对LED晶片图像灰度直方图的分析,根据其特有的三峰特性,改进了传统的最大类间方差法,采用Otsu双阈值法及新的评价函数求取高低阈值,从而避免传统Canny算法中阈值的人工调整。实验结果表明,这种方法适合LED晶片的边缘提取,并且能够获得良好的晶片边缘及两极轮廓。An improved Canny operator was proposed to ensure the accuracy of the Light Emitting Diode （LED） wafer edge detection applied in the vision system of automatic LED die bonder. In the traditional Non-Maxima Suppression （NMS） process, inaccuracy would be caused by selecting two pixels near gradient direction as contrastive points. To solve this problem, bilinear interpolation based on the center pixel and three pixels around was made along gradient direction to implement new NMS process. In addition, the gray histogram of LED wafer was characterized by typical three peaks, and then the high threshold and the low threshold could be got by Otsu dual threshold method with new evaluation function to replace traditional artificial adjustment. The experimental results indicate that greater wafer outline and poles edges can be got by the improved Canny algorithm which is appropriate for LED wafer edge detection.

关 键 词：CANNY算子 边缘检测 双线性插值 Otsu双阈值 发光二极管晶片 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]