3-Dimensional graphic image representation of holographic microscopical displacement pattern by using cubic spline function

For quantitative measurement of microscopical displacement of an object surface due to thermal stress, the holographic pattern measuring system (HPMS) has been developed by the authors, which is combined both the techniques of holographic interferometry and graphic image processing.

In this measuring sytem, a cubic spline function was applied to get the 3-dimensional graphic image patterns of the distribution of the displacement. The displacement is calculated from the interferometry fringe pattern, and the system was applied to deformation analysis of printed circuit board (PCB) due to thermal stress. The PCB deformation was expresed by 3-dimensional graphic image. A smooth curve could be obtained from rather less number of sampled data of interferometry fringe.