가변 구속상자를 이용한 점-표면배정방법에 의한 표면실장 솔더페이스트의 삼차원 해석 및 검사

Abstract

This work presents a method of point to surface assignment for 3D metrology of solder pastes on PCB. A bounding box enclosing the solder paste tightly on all sides is introduced to avoid incorrect assignment. The shape of bounding box for solder paste brick is variable according to geometry of measured points. The surface geometry of bounding box is obtained by using five peaks selected in the histogram of normalized gradient vectors. By using the bounding box enclosing the solder pastes, the task of point-to-surface assignment has been successfully conducted, then geometrical features are obtained through the task of surface fitting.