Automated Visual Inspection for Solder Joints of PCB Based on 3-D Image Analysis
Author(s) -
Toshifumi Honda,
Hisae Yamamura,
M. Nomoto,
Takanori Ninomiya,
Tomoharu Horii,
Yoshio MIYAWAKI
Publication year - 1999
Publication title -
journal of robotics and mechatronics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 19
eISSN - 1883-8049
pISSN - 0915-3942
DOI - 10.20965/jrm.1999.p0104
Subject(s) - automated optical inspection , soldering , fillet (mechanics) , artificial intelligence , printed circuit board , visual inspection , joint (building) , automated x ray inspection , computer vision , computer science , inspection time , laser scanning , specular reflection , image processing , laser , materials science , optics , engineering , image (mathematics) , structural engineering , psychology , developmental psychology , physics , composite material , operating system
Automated visual solder inspection was studied for different printed circuit boards (PCBs) based on 3-D-image analysis. The optical 3-D scanner accurately detects height of a solder joint from differently focused images of a laser spot. Emitted laser light on the solder joint is detected simultaneously by plural sensors whose focal points are set at different height to realize high-speed height acquisition without secondary-reflection problems caused by the specular surface of the solder joint. An inspection algorithm was designed to recognize a solder joint using detected height and the intensity image so that different shapes of solder fillet do not affect inspection performance. A solder joint is classified based on extracted 3-D features of its fillet shape and 3-D location of the lead from its pad. Inspection parameters are automatically generated with inspection parameter autogeneration using electronic component and PCB design data. Evaluation showed the system gave 100% defect detection and very few false alarms (0.13%) using autogenerated inspection parameters. Results show the technique to be promising in actual production lines for different PCBs.
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