Title :
An experimental vision system for SMD component placement inspection
Author :
Capson, David W. ; Tsang, Randy M C
Author_Institution :
Dept. of Electr. & Comput. Eng., McMaster Univ., Hamilton, Ont., Canada
Abstract :
An experimental system for automatic visual measurement of surface mount device (SMD) placement on printed circuit boards is described. Infrared illumination is used to aid in segmentation of component lead and solder pad images from the background. Best-fit lines through centroids of the lead and soldering pad images are calculated, from which the displacement and the angular orientation of the component relative to the pads is computed. Measurements are derived from a combination of slope and mean centroids from opposite sides of a device to reduce the effects of sensor resolution, missing pads, or missing leads. Experimental results of testing the accuracy of the system are reported. The results compare favorably with manufacturer´s placement tolerance specification and with measurements made manually
Keywords :
automatic optical inspection; computer vision; printed circuit manufacture; soldering; surface mount technology; IR illumination; SMD component placement inspection; angular orientation; automatic visual measurement; centroids; component lead images; mean centroids; missing leads; missing pads; placement tolerance specification; printed circuit boards; segmentation; sensor resolution; solder pad images; Electronics packaging; Infrared imaging; Inspection; Lead; Lighting; Machine vision; Manufacturing; Printed circuits; Soldering; Surface morphology;
Conference_Titel :
Industrial Electronics Society, 1990. IECON '90., 16th Annual Conference of IEEE
Conference_Location :
Pacific Grove, CA
Print_ISBN :
0-87942-600-4
DOI :
10.1109/IECON.1990.149245
