Circular Hole Center Detection for PCB Alignment by Using Improved Otsu Segmentation and Circle Hough Transform

• Main Authors: Shih-HsienChuang, 莊仕賢
• Other Authors: Jenn-Jier Lien
• Format: Others
• Language: en_US
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/21098866842806545831

碩士 === 國立成功大學 === 資訊工程學系 === 103 === This paper addresses a method for detections of a center of a circular shape of a target hole on Printed Circuit Board (PCB). Regarding positions of the target hole, alignments and arrangements of sockets with drilling on PCB for accommodation of other electronic components are made. However, this paper is aimed at robustness of localization of the target hole with proposed algorithms on consecutive images captured. With Circle Hough Transform algorithm, positioning error existence causes bad performance, i.e. non-robust data production. Because of this, it is not feasible that a drilling process of PCB is made. Therefore, in this paper, an automated positioning system for the target hole with Otsu segmentations is developed. Nonetheless, Otsu segmentation algorithm is not able to split an image into foreground and background when the foreground and background are not obviously different. Hence, improvement of Otsu segmentation is proposed. By comparing experimental results of the proposed and current Otsu segmentation, benefits of the proposed Otsu segmentation are verified. Besides, Connected Component Labeling is proposed to filter out noisy data on the foreground image. In order to enhance efficiency of noise removal, Run-Based One-Scan Labeling Algorithm is adopted. Then, Canny Edge Detection and Circle Hough Transform are used to locate the center of the circular shape of the target hole.