Vision alignment system in automatic high precision chip mounter and its image processing
Shi Tie-ling · Optical Technique · 2004
Accurate alignment is very crucial in the process of chip mounting. The structure and principle of vision alignment system in automatic high precision chip mounter are introduced. A method to judge the presence of fiducial by means of pattern recognition and moment invariants is presented.A method to align the two fiducials in chip and substrate is presented, and the related point pattern algorithm is detailed. Experiment results demonstrate that the proposed method to judge the presence of fiducial can effectively distinguish different fiducials, and judge whether the fiducial is in camera's field of view , and that the method to align fiducials can accurately get position offset between fiducials in chip and substrate even when the input image is rotated, translated, and fiducial is partly occulted.