High-speed and accurate profile measurement and defect inspection by scanning moire method using linear sensors

摘要

A new method for 3D surface profile measurement and surface defect inspection of a moving object is described. An interference fringe pattern is projected on a moving object as a grating. Then, the deformed gratings due to the profile of the object are acquired by three linear sensors successively. Since a linear sensor records the light intensity on a single line along the reference grating, the resultant image forms a scanning moire fringe pattern which represents the contour of the object profile. Using the images obtained by the three linear sensors, the phase distribution of the fringe pattern can be calculated by the phase-shifting method and the profile of the object is then evaluated quantitatively. Since the linear sensors can perform high-speed recording, the proposed method is expected to be applicable to several fields of inspection.